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Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in PKD1 and PKD2, encoding polycystin-1 (PC1) and polycystin-2 (PC2), which are required for the regulation of the renal tubular diameter. Loss of polycystin function results in cyst formation. Atypical forms of ADPKD are caused by mutations in genes encoding endoplasmic reticulum (ER)-resident proteins through mechanisms that are not well understood. Here, we investigate the function of DNAJB11, an ER co-chaperone associated with atypical ADPKD. We generated mouse models with constitutive and conditional Dnajb11 inactivation and Dnajb11-deficient renal epithelial cells to investigate the mechanism underlying autosomal dominant inheritance, the specific cell types driving cyst formation, and molecular mechanisms underlying DNAJB11-dependent polycystic kidney disease. We show that biallelic loss of Dnajb11 causes cystic kidney disease and fibrosis, mirroring human disease characteristics. In contrast to classical ADPKD, cysts predominantly originate from proximal tubules. Cyst formation begins in utero and the timing of Dnajb11 inactivation strongly influences disease severity. Furthermore, we identify impaired PC1 cleavage as a potential mechanism underlying DNAJB11-dependent cyst formation. Proteomic analysis of Dnajb11- and Pkd1-deficient cells reveals common and distinct pathways and dysregulated proteins, providing a foundation to better understand phenotypic differences between different forms of ADPKD., (© 2024 The Author(s). The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Background: Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a prevalent genetic disorder characterized by the formation of renal cysts leading to kidney failure. Despite known genetic underpinnings, the variability in disease progression suggests additional regulatory layers, including epigenetic modifications., Methods: We utilized various ADPKD models, including Pkd1 and Ezh2 conditional knockout (Pkd1 delta/delta :Ezh2 delta/delta ) mice, to explore the role of Enhancer of Zeste Homolog 2 (EZH2) in cystogenesis. Pharmacological inhibition of EZH2 was performed using GSK126 or EPZ-6438 across multiple models., Results: EZH2 expression was significantly upregulated in Pkd1 -/- cells, Pkd1 delta/delta mice, and human ADPKD kidneys. EZH2 inhibition attenuates cyst development in MDCK cells and a mouse embryonic kidney cyst model. Both Ezh2 conditional knockout and GSK126 treatment suppressed renal cyst growth and protected renal function in Pkd1 delta/delta mice. Mechanistically, cAMP/PKA/CREB pathway increased EZH2 expression. EZH2 mediated cystogenesis by enhancing methylation and activation of STAT3, promoting cell cycle through p21 suppression, and stimulating non-phosphorylated β-catenin in Wnt signaling pathway. Additionally, EZH2 enhanced ferroptosis by inhibiting SLC7A11 and GPX4 in ADPKD., Conclusion: Our findings elucidate the pivotal role of EZH2 in promoting renal cyst growth through epigenetic mechanisms and suggest that EZH2 inhibition or ablation may serve as a novel therapeutic approach for managing ADPKD., (© 2024. The Author(s).)

Objective: To analyze and clarify the clinical and pathogenic gene variation and genetic etiology of polycystic liver disease. Methods: The proband clinical data and family history were collected. Whole-exome sequencing technology was used to detect the proband gene variations. Fluorescence quantitative PCR validation was performed on the proband and his family to screen out pathogenic gene variation. Results: A multiple liver cyst was found in an 18-year-old male proband during a physical examination. There were no abnormalities in his liver function, and both his father and grandfather had multiple liver cysts without any obvious discomfort or other special manifestations. Whole exome sequencing suggested a heterozygous deletion in exon 1 (Exon 1) of the SEC63 gene in the proband. Real-time fluorescence quantitative PCR confirmed that the heterozygous deletion variation of the SEC63 gene Exon 1 of the proband came from his father, and the same heterozygous deletion was detected in his grandfather. The gene variant had a pathogenic variation that had been rarely reported before and was in accordance with the the American college of Medical Genetics and Genomics (ACMG) guidelines. Conclusions: The genetic etiology of this autosomal dominant polycystic liver disease has been clarified, and the heterozygous deletion of Exon1 of the SEC63 gene is a newly discovered gene variation that broadens the variation spectrum of the SEC63 gene.

Peritoneal inclusion cysts (PICs) are unilocular or multilocular cystic lesions lined by bland mesothelial cells. While most are small and localized, rare examples may be large or multifocal with diffuse peritoneal involvement, causing clinical and even pathologic concern for malignancy. We examined 20 PIC, including 8 large solitary and 12 multifocal lesions. Solitary PIC were found in 7 female and 1 male patients ranging from 19 to 55 (median: 37) years. Expanded collagenous (n=2) or edematous (n=1) areas were occasionally seen in the septae, and 1 had microscopic foci of myxoid stroma. Four had hobnail cells, and 1 had minor areas of papillary mesothelial hyperplasia. Multifocal PICs occurred in 9 female and 3 male patients ranging from 26 to 80 (median: 53) years. Three showed extensive associated fibrosis with entrapment of preexisting adipose tissue, 2 had areas resembling granulation tissue, and 3 had scattered foci of myxoid stroma. Hobnail cells were present in 9, papillary mesothelial hyperplasia in 2, entrapped single cells in 1, and 2 had areas resembling adenomatoid tumors. Two of the multifocal PICs had limited local recurrences at 18 and 21 months. No patients died of disease. Clonal alterations were not identified in any of the tested PICs (mutational and fusion analysis in 5, chromosomal microarray in 1). Despite limited local recurrences, we demonstrate that even large and multifocal PICs may lack identifiable genomic alterations and are associated with benign outcomes., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Clinical variability among individuals with heterozygous pathogenic/likely pathogenic (P/LP) variants in the COL4A3/COL4A4 genes (also called autosomal dominant Alport syndrome or COL4A3/COL4A4-related disorder) is huge; many individuals are asymptomatic or show microhematuria, while others may develop proteinuria and chronic kidney disease (CKD). The prevalence of simple kidney cysts (KC) in the general population varies according to age, and patients with advanced CKD are prone to have them. A possible association between heterozygous COL4A3, COL4A4 and COL4A5 P/LP variants and KC has been described in small cohorts. The presence of KC in a multicenter cohort of individuals with heterozygous P/LP variants in the COL4A3/COL4A4 genes is assessed in this study., Methods: We evaluated the presence of KC by ultrasound in 157 individuals with P/LP variants in COL4A3 (40.7%) or COL4A4 (53.5%) without kidney replacement therapy. The association between presence of KC and age, proteinuria, estimated glomerular filtration rate (eGFR) and causative gene was analyzed. Prevalence of KC was compared with historical case series in the general population., Results: Half of the individuals with P/LP variants in COL4A3/COL4A4 showed KC, which is a significantly higher percentage than in the general population. Only 3.8% (6/157) had cystic nephromegaly. Age and eGFR showed an association with the presence of KC (P < .001). No association was found between KC and proteinuria, sex or causative gene., Conclusions: Individuals with COL4A3/COL4A4 P/LP variants are prone to develop KC more frequently than the general population, and their presence is related to age and to eGFR. Neither proteinuria, sex nor the causative gene influences the presence of KC in these individuals., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

A new gene-cell construct expressing nerve growth factor (NGF) has been developed. After obtaining engineered adenovectors Ad5-RGD-CAG-NGF and Ad5-RGD-CAG-EGFP, transduction efficiency and transgene expression were studied and multiplicity of infection was determined. The efficacy of transduced human olfactory ensheathing cells expressing NGF in restoring motor activity in rats has been shown in a limited period of time. Improved rat hindlimb mobility and cyst size reduction after gene-cell construct transplantation were more likely due to the cellular component of the construct., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature.)

The purpose of this study is to analyze the clinical characteristics of patients with Van der Woude syndrome (VWS) and to detect variations in each patient. Finally, the combination of genotype and phenotype can make a clear diagnosis of VWS patients with different phenotype penetrance., Five Chinese VWS pedigree were enrolled. Whole exome sequencing of the proband was performed, and the potential pathogenic variation was further verified by Sanger sequencing in the patient and their parents. The human mutant IRF6 coding sequence was generated from the human full-length IRF6 plasmid by site-directed mutagenesis and cloned into the GV658 vector, RT-qPCR and Western blot were used to detect the expression of IRF6 ., We found one de novo nonsense variation (p. Gln118Ter) and three novel missense variations (p. Gly301Glu, p. Gly267Ala, and p. Glu404Gly) co-segregated with VWS. RT-qPCR analysis revealed that p. Glu404Gly significantly reduced the expression level of IRF6 mRNA. Western blot of cell lysates confirmed that IRF6 p. Glu404Gly abundance levels were lower than those for IRF6 wild type., This discovery of the novel variation ( IRF6 p. Glu404Gly) expands the spectrum of known variations in VWS in Chinese humans. Genetic results combined with clinical phenotypes and differential diagnosis points from other diseases can make a definitive diagnosis and provide genetic counseling for families., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1 -related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants., Methods: Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/ DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis., Results: In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB., Conclusion: Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention., Competing Interests: Competing interests: Dr Hill is the owner of ResourcePath LLC, a company which does research and development of laboratory tests including for DICER1-related cancers. The work is unrelated to the information presented in this article. Dr Stewart provides telegenetics services for Genome Medical, Inc, in accordance with relevant National Cancer Institute policies. The remaining authors have no conflicts to disclose., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Abnormal lung development can cause congenital pulmonary cysts, the mechanisms of which remain largely unknown. Although the cystic lesions are believed to result directly from disrupted airway epithelial cell growth, the extent to which developmental defects in lung mesenchymal cells contribute to abnormal airway epithelial cell growth and subsequent cystic lesions has not been thoroughly examined. In the present study using genetic mouse models, we dissected the roles of bone morphogenetic protein (BMP) receptor 1a (Bmpr1a)-mediated BMP signaling in lung mesenchyme during prenatal lung development and discovered that abrogation of mesenchymal Bmpr1a disrupted normal lung branching morphogenesis, leading to the formation of prenatal pulmonary cystic lesions. Severe deficiency of airway smooth muscle cells and subepithelial elastin fibers were found in the cystic airways of the mesenchymal Bmpr1a knockout lungs. In addition, ectopic mesenchymal expression of BMP ligands and airway epithelial perturbation of the Sox2-Sox9 proximal-distal axis were detected in the mesenchymal Bmpr1a knockout lungs. However, deletion of Smad1/5, two major BMP signaling downstream effectors, from the lung mesenchyme did not phenocopy the cystic abnormalities observed in the mesenchymal Bmpr1a knockout lungs, suggesting that a Smad-independent mechanism contributes to prenatal pulmonary cystic lesions. These findings reveal for the first time the role of mesenchymal BMP signaling in lung development and a potential pathogenic mechanism underlying congenital pulmonary cysts., Competing Interests: YL, KC, JC, HC, HW, MT, BG, MK, MP, YM, WS No competing interests declared, (© 2023, Luo et al.)

Hepatic cystadenoma is a rare disease, accounting for about 5% of all cystic lesions, with a high tendency of malignant transformation. The preoperative diagnosis of cystadenoma is difficult, and some cystadenomas are easily misdiagnosed as hepatic cysts at first. Hepatic cyst is a relatively common liver disease, most of which are benign, but large hepatic cysts can lead to pressure on the bile duct, resulting in abnormal liver function. To better understand the difference between the microenvironment of cystadenomas and hepatic cysts, we performed single-nuclei RNA-sequencing on cystadenoma and hepatic cysts samples. In addition, we performed spatial transcriptome sequencing of hepatic cysts. Based on nucleus RNA-sequencing data, a total of seven major cell types were identified. Here we described the tumor microenvironment of cystadenomas and hepatic cysts, particularly the transcriptome signatures and regulators of immune cells and stromal cells. By inferring copy number variation, it was found that the malignant degree of hepatic stellate cells in cystadenoma was higher. Pseudotime trajectory analysis demonstrated dynamic transformation of hepatocytes in hepatic cysts and cystadenomas. Cystadenomas had higher immune infiltration than hepatic cysts, and T cells had a more complex regulatory mechanism in cystadenomas than hepatic cysts. Immunohistochemistry confirms a cystadenoma-specific T-cell immunoregulatory mechanism. These results provided a single-cell atlas of cystadenomas and hepatic cyst, revealed a more complex microenvironment in cystadenomas than in hepatic cysts, and provided new perspective for the molecular mechanisms of cystadenomas and hepatic cyst., Competing Interests: Declaration of competing interest This paper is a full-length manuscript that has not simultaneously been submitted elsewhere for print or electronic publication. This submission has been agreed by all the co-authors for this paper. All the co-authors declare no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: Cystic lung diseases are rare, with numerous differential diagnoses. Iconographic discovery consequently necessitates medical examinations in view of proposing an etiological orientation., Case Report: A 57-year-old woman consulted in pulmonology following fortuitous detection of a cystic lung disease on an abdominal CT scan. Complementary medical examinations did not allow orientation towards a particular diagnosis. During a follow-up consultation, the patient informed her pulmonologist of the recent detection of a monoallelic variant of a FAT4 gene in one of her daughters, who was suffering from edema of the lower limbs secondary to a disease of the lymphatic system. As our patient had a similar history, she likewise received a genetic analysis. A monoallelic variant not described in the genetic databases was observed, and considered as a probable pathogenic variant (class 4/5 on the pathogenicity scale of genetic variants)., Conclusion: After analyzing the available literature data, we raise questions about a possible link between this variant of the FAT4 gene, chronic lymphedema and our patient's cystic lung disease., (Copyright © 2024 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Subarachnoid neurocysticercosis (SANCC) is caused by an abnormally transformed form of the metacestode or larval form of the tapeworm Taenia solium. In contrast to vesicular parenchymal and ventricular located cysts that contain a viable scolex and are anlage of the adult tapeworm, the subarachnoid cyst proliferates to form aberrant membranous cystic masses within the subarachnoid spaces that cause mass effects and acute and chronic arachnoiditis. How subarachnoid cyst proliferates and interacts with the human host is poorly understood, but parasite stem cells (germinative cells) likely participate. RNA-seq analysis of the subarachnoid cyst bladder wall compared to the bladder wall and scolex of the vesicular cyst revealed that the subarachnoid form exhibits activation of signaling pathways that promote proliferation and increased lipid metabolism. These adaptions allow growth in a nutrient-limited cerebral spinal fluid. In addition, we identified therapeutic drug targets that would inhibit growth of the parasite, potentially increase effectiveness of treatment, and shorten its duration., (© 2024. The Author(s).)

Background & Aims: Autosomal dominant polycystic liver disease is a rare condition with a female preponderance, based mainly on pathogenic variants in 2 genes, PRKCSH and SEC63. Clinically, autosomal dominant polycystic liver disease is characterized by vast heterogeneity, ranging from asymptomatic to highly symptomatic hepatomegaly. To date, little is known about the prediction of disease progression at early stages, hindering clinical management, genetic counseling, and the design of randomized controlled trials. To improve disease prognostication, we built a consortium of European and US centers to recruit the largest cohort of patients with PRKCSH and SEC63 liver disease., Methods: We analyzed an international multicenter cohort of 265 patients with autosomal dominant polycystic liver disease harboring pathogenic variants in PRKCSH or SEC63 for genotype-phenotype correlations, including normalized age-adjusted total liver volumes and polycystic liver disease-related hospitalization (liver event) as primary clinical end points., Results: Classifying individual total liver volumes into predefined progression groups yielded predictive risk discrimination for future liver events independent of sex and underlying genetic defects. In addition, disease severity, defined by age at first liver event, was considerably more pronounced in female patients and patients with PRKCSH variants than in those with SEC63 variants. A newly developed sex-gene score was effective in distinguishing mild, moderate, and severe disease, in addition to imaging-based prognostication., Conclusions: Both imaging and clinical genetic scoring have the potential to inform patients about the risk of developing symptomatic disease throughout their lives. The combination of female sex, germline PRKCSH alteration, and rapid total liver volume progression is associated with the greatest odds of polycystic liver disease-related hospitalization., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Polycystic liver disease (PLD) is a rare condition observed in three genetic diseases, including autosomal dominant polycystic liver disease (ADPLD), autosomal dominant polycystic kidney disease (ADPKD), and autosomal recessive polycystic kidney disease (ARPKD). PLD usually does not impair liver function, and advanced PLD becomes symptomatic when the enlarged liver compresses adjacent organs or increases intra-abdominal pressure. Currently, the diagnosis of PLD is mainly based on imaging, and genetic testing is not required except for complex cases. Besides, genetic testing may help predict patients' prognosis, classify patients for genetic intervention, and conduct early treatment. Although the underlying genetic causes and mechanisms are not fully understood, previous studies refer to primary ciliopathy or impaired ciliogenesis as the main culprit. Primarily, PLD occurs due to defective ciliogenesis and ineffective endoplasmic reticulum quality control. Specifically, loss of function mutations of genes that are directly involved in ciliogenesis, such as Pkd1, Pkd2, Pkhd1, and Dzip1l, can lead to both hepatic and renal cystogenesis in ADPKD and ARPKD. In addition, loss of function mutations of genes that are involved in endoplasmic reticulum quality control and protein folding, trafficking, and maturation, such as PRKCSH, Sec63, ALG8, ALG9, GANAB, and SEC61B, can impair the production and function of polycystin1 (PC1) and polycystin 2 (PC2) or facilitate their degradation and indirectly promote isolated hepatic cystogenesis or concurrent hepatic and renal cystogenesis. Recently, it was shown that mutations of LRP5, which impairs canonical Wnt signaling, can lead to hepatic cystogenesis. PLD is currently treated by somatostatin analogs, percutaneous intervention, surgical fenestration, resection, and liver transplantation. In addition, based on the underlying molecular mechanisms and signaling pathways, several investigational treatments have been used in preclinical studies, some of which have shown promising results. This review discusses the clinical manifestation, complications, prevalence, genetic basis, and treatment of PLD and explains the investigational methods of treatment and future research direction, which can be beneficial for researchers and clinicians interested in PLD., (© 2024. The Author(s).)

In polycystic kidney disease (PKD), microscopic tubules expand into macroscopic cysts. Among the world's most common genetic disorders, PKD is inherited via heterozygous loss-of-function mutations but is theorized to require additional loss of function. To test this, we establish human pluripotent stem cells in allelic series representing four common nonsense mutations, using CRISPR base editing. When differentiated into kidney organoids, homozygous mutants spontaneously form cysts, whereas heterozygous mutants (original or base corrected) express no phenotype. Using these, we identify eukaryotic ribosomal selective glycosides (ERSGs) as PKD therapeutics enabling ribosomal readthrough of these same nonsense mutations. Two different ERSGs not only prevent cyst initiation but also limit growth of pre-formed cysts by partially restoring polycystin expression. Furthermore, glycosides accumulate in cyst epithelia in organoids and mice. Our findings define the human polycystin threshold as a surmountable drug target for pharmacological or gene therapy interventions, with relevance for understanding disease mechanisms and future clinical trials., Competing Interests: Declaration of interests Eloxx Pharmaceuticals is developing ELX-02 and ELX-10 as investigational drugs and holds patents related to their use (WO2021061873A1, WO2019237076A1). B.S.F. is an inventor on patents and/or patent applications related to human kidney organoid differentiation and modeling of PKD in this system (US20200377860A1, WO2019222559A1). B.S.F. holds ownership interest in Plurexa LLC., (Copyright © 2024. Published by Elsevier Inc.)

A properly regulated series of developmental and meiotic events must occur to ensure the successful production of gametes. In Drosophila melanogaster ovaries, these early developmental and meiotic events include the production of the 16-cell cyst, meiotic entry, synaptonemal complex (SC) formation, recombination, and oocyte specification. In order to identify additional genes involved in early oocyte development and meiosis, we reanalyzed 3 published single-cell RNA-seq datasets from Drosophila ovaries, using vasa (germline) together with c(3)G, cona, and corolla (SC) as markers. Our analysis generated a list of 2,743 co-expressed genes. Many known SC-related and early oocyte development genes fell within the top 500 genes on this list, as ranked by the abundance and specificity of each gene's expression across individual analyses. We tested 526 available RNAi lines containing shRNA constructs in germline-compatible vectors representing 331 of the top 500 genes. We assessed targeted ovaries for SC formation and maintenance, oocyte specification, cyst development, and double-strand break dynamics. Six uncharacterized genes exhibited early developmental defects. SC and developmental defects were observed for additional genes not well characterized in the early ovary. Interestingly, in some lines with developmental delays, meiotic events could still be completed once oocyte specificity occurred indicating plasticity in meiotic timing. These data indicate that a transcriptomics approach can be used to identify genes involved in functions in a specific cell type in the Drosophila ovary., Competing Interests: Conflicts of interest. The author(s) declare no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Genetics Society of America.)

Disease-causing variants in HEPACAM are associated with megalencephalic leukoencephalopathy with subcortical cysts 2A (MLC2A, MIM# 613,925, autosomal recessive), and megalencephalic leukoencephalopathy with subcortical cysts 2B, remitting, with or without impaired intellectual development (MLC2B, MIM# 613,926, autosomal dominant). These disorders are characterised by macrocephaly, seizures, motor delay, cognitive impairment, ataxia, and spasticity. Brain magnetic resonance imaging (MRI) in these individuals shows swollen cerebral hemispheric white matter and subcortical cysts, mainly in the frontal and temporal regions. To date, 45 individuals from 39 families are reported with biallelic and heterozygous variants in HEPACAM, causing MLC2A and MLC2B, respectively. A 9-year-old male presented with developmental delay, gait abnormalities, seizures, macrocephaly, dysarthria, spasticity, and hyperreflexia. MRI revealed subcortical cysts with diffuse cerebral white matter involvement. Whole-exome sequencing (WES) in the proband did not reveal any clinically relevant single nucleotide variants. However, copy number variation analysis from the WES data of the proband revealed a copy number of 4 for exons 3 and 4 of HEPACAM. Validation and segregation were done by quantitative PCR which confirmed the homozygous duplication of these exons in the proband and carrier status in both parents. To the best of our knowledge, this is the first report of an intragenic duplication in HEPACAM causing MLC2A., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: As part of the National Disease Surveillance Program for Taiwanese Aquaculture, we investigated the causative agent of disease outbreaks in farmed Chicken Grunts Parapristipoma trilineatum., Methods: In this study, outbreak cases on two separate farms were noticed in coastal Pingtung County, Taiwan. In total, 50 juvenile fish showing clinical signs (such as emaciation and erratic swimming behavior) and broodstock (two females and two males) from both farms were collected to perform gross lesion assessment, histopathological examination, and molecular identification of the pathogen., Result: Clinical symptoms were infected fish exhibited erratic swimming behavior, such as whirling and floating on the surface of the water. In the following months, cumulative mortality had reached 19% and 24%, respectively. The gross lesions in the infected fish included white oval cysts in the muscle, serosa of the internal organs, sclera of the eyes, and cerebral meninges. After conducting a wet mount examination of cysts using a light microscope, we observed a significant quantity of spores with morphological characteristics, suggesting their affiliation with the Myxosporea group. The spores were semiquadrate, with four tiny suture notches at the periphery; the mean spore length was 7.3 μm (SD = 0.5), and the mean spore width was 8.2 μm (SD = 0.6). The mean length and width of the pyriform polar capsules (nematocysts) were 3.6 μm (SD = 0.5) and 2.2 μm (SD = 0.5), respectively. The 18S and 28S ribosomal RNA sequences of these specimens were identical to those of Kudoa lutjanus., Conclusion: As this was the first time an outbreak of K. lutjanus in Chicken Grunts was confirmed, its reappearance with substantial mortality should serve as a warning to the aquaculture industry., (© 2023 American Fisheries Society.)

Initial cysts that are formed upon Pkd1 loss in mice impose persistent stress on surrounding tissue and trigger a cystic snowball effect, in which local aberrant PKD-related signaling increases the likelihood of new cyst formation, ultimately leading to accelerated disease progression. Although many pathways have been associated with PKD progression, the knowledge of early changes near initial cysts is limited. To perform an unbiased analysis of transcriptomic alterations in the cyst microenvironment, microdomains were collected from kidney sections of iKsp-Pkd1 del mice with scattered Pkd1-deletion using Laser Capture Microdissection. These microdomains were defined as F4/80-low cystic, representing early alterations in the cyst microenvironment, F4/80-high cystic, with more advanced alterations, or non-cystic. RNA sequencing and differential gene expression analysis revealed 953 and 8088 dysregulated genes in the F4/80-low and F4/80-high cyst microenvironment, respectively, when compared to non-cystic microdomains. In the early cyst microenvironment, several injury-repair, growth, and tissue remodeling-related pathways were activated, accompanied by mild metabolic changes. In the more advanced F4/80-high microdomains, these pathways were potentiated and the metabolism was highly dysregulated. Upstream regulator analysis revealed a series of paracrine factors with increased activity in the early cyst microenvironment, including TNFSF12 and OSM. In line with the upstream regulator analysis, TWEAK and Oncostatin-M promoted cell proliferation and inflammatory gene expression in renal epithelial cells and fibroblasts in vitro. Collectively, our data provide an overview of molecular alterations that specifically occur in the cyst microenvironment and identify paracrine factors that may mediate early and advanced alterations in the cyst microenvironment., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: D.J.M. Peters reports financial support was provided by Dutch Kidney Foundation. D.J.M. Peters reports a relationship with Mironid Ltd. that includes: consulting or advisory. D.J.M. Peters reports a relationship with Crown Bioscience Inc. that includes: consulting or advisory. D.J.M. Peters reports a relationship with Innoser Laboratories BV that includes: consulting or advisory., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Small air-filled peripheral subpleural cysts are a well-described feature of pulmonary anatomy at computerized tomographic (CT) scan in children with Trisomy 21, yet only anecdotally described in association with other pathologies. The significance of these cysts is unknown., Objective: To investigate and explore the pathogenesis of these subpleural cysts in children., Materials and Methods: A retrospective review of 16 cases with subpleural cysts diagnosed on CT chest was performed. The distribution, location, and ancillary CT findings were recorded. Hospital charts were reviewed for clinical details, especially cardiac abnormalities, pulmonary artery hypertension (PAH) and genetic associations. Histopathological and clinical correlative data were recorded., Results: Eleven of the 16 children (69%) were found to have an underlying chromosomal or genetic abnormality, six of whom had Trisomy 21. The remaining 5 of the 16 cases (21%) had miscellaneous disorders without an identifiable genetic basis. The most common co-morbidities were cardiac abnormalities (81%) and PAH (62.5%). Regardless of their underlying etiologies, the cysts were present bilaterally in most cases (14/16, 88%). We observed both the postnatal development and the progression of cysts in our cohort. On long-term follow-up, there were five deaths (31%) and six cases (38%) requiring maintenance oxygen therapy due to chronic hypoxia. Two cases (12.5%) became completely asymptomatic after correction of their underlying abnormalities., Conclusion: Subpleural cysts are not exclusive to Trisomy 21 and may be seen in other inherited or acquired causes, likely due to altered alveolar growth. We suspect these cysts are a sign of an underlying developmental disorder with variable clinical effect, especially in children with congenital cardiac disease., (© 2023 The Authors. Pediatric Pulmonology published by Wiley Periodicals LLC.)

α-1,2-mannosyltransferase ( ALG9 ) germline variants are linked to autosomal dominant polycystic kidney disease (ADPKD). Many individuals affected with ADPKD possess polycystic livers as a common extrarenal manifestation. We performed whole exome sequencing in a female with autosomal dominant polycystic liver disease (ADPLD) without kidney cysts and established the presence of a heterozygous missense variant (c.677G>C p.(Gly226Ala)) in ALG9 . In silico pathogenicity prediction and 3D protein modeling determined this variant as pathogenic. Loss of heterozygosity is regularly seen in liver cyst walls. Immunohistochemistry indicated the absence of ALG9 in liver tissue from this patient. ALG9 expression was absent in cyst wall lining from ALG9 - and PRKCSH -caused ADPLD patients but present in the liver cyst lining derived from an ADPKD patient with a PKD2 variant. Thus, heterozygous pathogenic variants in ALG9 are also associated with ADPLD. Somatic loss of heterozygosity of the ALG9 enzyme was seen in the ALG9 patient but also in ADPLD patients with a different genetic background. This expanded the phenotypic spectrum of ADPLD to ALG9 .

Significance Statement: Heterozygous DNAJB11 mutation carriers manifest with small cystic kidneys and renal failure in adulthood. Recessive cases with prenatal cystic kidney dysplasia were recently described. Our in vitro and mouse model studies investigate the proposed disease mechanism as an overlap of autosomal-dominant polycystic kidney disease and autosomal-dominant tubulointerstitial kidney disease pathogenesis. We find that DNAJB11 loss impairs cleavage and maturation of the autosomal-dominant polycystic kidney disease protein polycystin-1 (PC1) and results in dosage-dependent cyst formation in mice. We find that Dnajb11 loss does not activate the unfolded protein response, drawing a fundamental contrast with the pathogenesis of autosomal-dominant tubulointerstitial kidney disease. We instead propose that fibrosis in DNAJB11 -kidney disease may represent an exaggerated response to polycystin-dependent cysts., Background: Patients with heterozygous inactivating mutations in DNAJB11 manifest with cystic but not enlarged kidneys and renal failure in adulthood. Pathogenesis is proposed to resemble an overlap of autosomal-dominant polycystic kidney disease (ADPKD) and autosomal-dominant tubulointerstitial kidney disease (ADTKD), but this phenotype has never been modeled in vivo . DNAJB11 encodes an Hsp40 cochaperone in the endoplasmic reticulum: the site of maturation of the ADPKD polycystin-1 (PC1) protein and of unfolded protein response (UPR) activation in ADTKD. We hypothesized that investigation of DNAJB11 would shed light on mechanisms for both diseases., Methods: We used germline and conditional alleles to model Dnajb11 -kidney disease in mice. In complementary experiments, we generated two novel Dnajb11-/- cell lines that allow assessment of PC1 C-terminal fragment and its ratio to the immature full-length protein., Results: Dnajb11 loss results in a profound defect in PC1 cleavage but with no effect on other cystoproteins assayed. Dnajb11-/- mice are live-born at below the expected Mendelian ratio and die at a weaning age with cystic kidneys. Conditional loss of Dnajb11 in renal tubular epithelium results in PC1 dosage-dependent kidney cysts, thus defining a shared mechanism with ADPKD. Dnajb11 mouse models show no evidence of UPR activation or cyst-independent fibrosis, which is a fundamental distinction from typical ADTKD pathogenesis., Conclusions: DNAJB11 -kidney disease is on the spectrum of ADPKD phenotypes with a PC1-dependent pathomechanism. The absence of UPR across multiple models suggests that alternative mechanisms, which may be cyst-dependent, explain the renal failure in the absence of kidney enlargement., (Copyright © 2023 by the American Society of Nephrology.)

Leukoencephalopathy with calcifications and cysts (LCC; OMIM #614561) is a rare disease and at present there are less than 100 cases reported worldwide. Mutations in the SNORD118 gene is now known to be the cause of LCC. We present a case who was heterozygous for the n.70G>A and n.6C>T sequence variants of the SNORD118 gene, variants which to date have not been described. Compared with the cases that we reviewed, our patient had the second longest time to diagnosis (age 56) from onset of symptoms 40 years prior. Moreover, his cousin's family has a high prevalence of epilepsy. This paper reviewed all published reports to date that had descriptive cases involving LCC as well as testing for the SNORD118 gene. Since 1996 only 85 patients have been described in 59 case reports. In this review, we summarize their clinical features, especially central nervous system symptoms, treatment, pathology, and gene testing results., (© 2023. Fondazione Società Italiana di Neurologia.)

Background: The clinical pulmonary manifestations and genetic features of Birt-Hogg-Dubé syndrome (BHDS) in Asian patients remained unclear. We aimed to clarify the clinical features of BHDS-associated pneumothorax (PTX) and retrospectively investigate potential contributing factors in the largest Asian cohort to date., Methods: We reviewed the clinical and genetic data collected in 2006-2017, from the BHDS patients who were Asian and presented with pulmonary cysts with or without a history of PTX., Results: Data from 334 (41.3% males; 58.7% females) patients from 297 unrelated families were reviewed. Among them, 314 (94.0%) patients developed PTX. The median age at the first occurrence of PTX was 32 years, which was significantly lower in males (P = 0.003) and patients without notable skin manifestations (P < 0.001). Seventy-six (24.2%) patients experienced their first PTX episode before the age of 25 years. PTX simultaneously occurred in the bilateral lungs of 37 (11.8%) patients. Among 149 patients who had their first PTX episode at least 10 years before BHDS diagnosis, PTX occurred more frequently in males (P = 0.030) and light smokers than in nonsmokers (P = 0.014). The occurrence of PTX peaked in the early 30s and gradually decreased with age but remained high in females (P = 0.001). We identified 70 unique FLCN germline variants, including duplications (46.4%), substitutions (7.1%), insertions/deletions (30.0%), and variants affecting splicing (12.5%). Approximately 80% of Asian patients suspected of having BHDS could be genetically diagnosed by examining FLCN exons 7, 9, 11, 12, and 13. No apparent genotype-phenotype correlation regarding pulmonary manifestations was identified., Conclusions: Our findings indicate that sex, smoking history, and skin manifestations at BHDS diagnosis significantly influence the clinical features of BHDS-associated PTX. These findings may contribute to the appropriate management and treatment of BHDS-associated PTX., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Namba et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Rationale: Birt-Hogg-Dubé (BHD) syndrome is a rare autosomal recessive genetic disorder caused mainly by mutations in the tumor suppressor FLCN gene. Tumors caused by FLCN mutations are frequently benign and develop in skin, lungs, kidney, and other organs, leading to a variety of phenotypes that make early diagnoses of BHD challenging., Patient Concerns: A 51-year-old female was admitted to Shanghai Seventh People Hospital due to chest congestion and dyspnea that had persisted for 3 years and aggravated for 1 month. She had been diagnosed with pneumothorax prior to this submission, but the etiology was unknown., Diagnoses: Chest computed tomography (CT) revealed multiple pulmonary cysts and pneumothorax, and her family members shared similar manifestation. Whole-exome sequencing analysis indicated a heterozygous FLCN splicing mutation (c.1432 + 1G > A; rs755959303), which was a pathogenic variant indicated in ClinVar. Based on FLCN mutation and the family history of pulmonary cysts and pneumothorax, BHD syndrome was finally diagnosed, which had been delayed for 3 years since her first pneumothorax., Interventions: Pulmonary bullectomy and pleurodesis were finally conducted due to the poor effects of thoracic close drainage., Outcomes: Her pneumothorax was resolved, and no recurrence was found in 2 years., Lessons: Our study highlights the importance of genetic analysis in diagnosis and clinical management of BHD syndrome., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Cystic kidney diseases, when broadly defined, have a wide differential diagnosis extending from recessive diseases with a prenatal or pediatric diagnosis, to the most common autosomal-dominant polycystic kidney disease primarily affecting adults, and several other genetic or acquired etiologies that can manifest with kidney cysts. The most likely diagnoses to consider when assessing a patient with cystic kidney disease differ depending on family history, age stratum, radiologic characteristics, and extrarenal features. Accurate identification of the underlying condition is crucial to estimate the prognosis and initiate the appropriate management, identification of extrarenal manifestations, and counseling on recurrence risk in future pregnancies. There are significant differences in the clinical approach to investigating and managing kidney cysts in children compared with adults. Next-generation sequencing has revolutionized the diagnosis of inherited disorders of the kidney, despite limitations in access and challenges in interpreting the data. Disease-modifying treatments are lacking in the majority of kidney cystic diseases. For adults with rapid progressive autosomal-dominant polycystic kidney disease, tolvaptan (V2-receptor antagonist) has been approved to slow the rate of decline in kidney function. In this article, we examine the differences in the differential diagnosis and clinical management of cystic kidney disease in children versus adults, and we highlight the progress in molecular diagnostics and therapeutics, as well as some of the gaps meriting further attention., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Although very uncommon, severe injury and death can occur during scuba diving. One of the main causes of scuba diving fatalities is pulmonary barotrauma due to significant changes in ambient pressure. Pathology of the lung parenchyma, such as cystic lesions, might increase the risk of pulmonary barotrauma., Areas Covered: Birt-Hogg-Dubé syndrome (BHD), caused by pathogenic variants in the FLCN gene, is characterized by skin fibrofolliculomas, an increased risk of renal cell carcinoma, multiple lung cysts and spontaneous pneumothorax. Given the pulmonary involvement, in some countries patients with BHD are generally recommended to avoid scuba diving, although evidence-based guidelines are lacking. We aim to provide recommendations on scuba diving for patients with BHD, based on a survey of literature on pulmonary cysts and pulmonary barotrauma in scuba diving., Expert Opinion: In our opinion, although the absolute risks are likely to be low, caution is warranted. Given the relative paucity of literature and the potential fatal outcome, patients with BHD with a strong desire for scuba diving should be informed of the potential risks in a personal assessment. If available a diving physician should be consulted, and a low radiation dose chest computed tomography (CT)-scan to assess pulmonary lesions could be considered.

The purpose of the present study was to determine the role of inositol 1,4,5-trisphosphate receptor 3 (IP 3 R3) in renal cyst development in autosomal dominant polycystic kidney disease (ADPKD). 2-aminoethoxy-diphenyl borate (2-APB) and shRNA were used to suppress the expression of IP 3 R3. The effect of IP 3 R3 on cyst growth was investigated in Madin-Darby canine kidney (MDCK) cyst model, embryonic kidney cyst model and kidney specific Pkd1 knockout (PKD) mouse model. The underlying mechanism of IP 3 R3 in promoting renal cyst development was investigated by Western blot and immunofluorescence staining. The results showed that the expression level of IP 3 R3 was significantly increased in the kidneys of PKD mice. Inhibiting IP 3 R3 by 2-APB or shRNA significantly retarded cyst expansion in MDCK cyst model and embryonic kidney cyst model. Western blot and immunofluorescence staining results showed that hyperactivated cAMP-PKA signaling pathway in the growth process of ADPKD cyst promoted the expression of IP 3 R3, which was accompanied by a subcellular redistribution process in which IP 3 R3 was translocated from endoplasmic reticulum to intercellular junction. The abnormal expression and subcellular localization of IP 3 R3 further promoted cyst epithelial cell proliferation by activating MAPK and mTOR signaling pathways and accelerating cell cycle. These results suggest that the expression and subcellular distribution of IP 3 R3 are involved in promoting renal cyst development, which implies IP 3 R3 as a potential therapeutic target of ADPKD.

Presented are four cystic renal masses which harbored a MED15::TFE3 gene fusion detected by RNAseq, mimicking multilocular cystic neoplasm of low malignant potential. Clinicopathologic and outcomes data were collected for all cases. Radiologically, three cases were diagnosed as complex cystic masses and one case as a renal cyst, three years prior to surgery. The tumors ranged in size from 1.8 to 14.5 cm. Grossly, all masses were extensively cystic. Microscopically, cells with a clear or minimally granular cytoplasm and nuclei with inconspicuous nucleoli lined the cysts' septa. Focally, small mass-forming aggregates of malignant cells were present between septae and were associated with psammomatous calcifications. In case one, apparent prior cyst wall rupture was associated with reactive changes and cystic spaces filled with fibrin clots. Two of the tumors were staged as T1a, one as T1b, and the other as T2b. By immunohistochemistry, the tumors were positive for TFE3, MelanA, and P504S, with apical CD10 while CAIX and CK7 were negative. RNA sequencing was performed on all cases revealing a MED15::TFE3 gene fusion. The patients were alive and without evidence of disease 11-49 months (mean 29.5) after partial nephrectomy. To date, 12 of the 15 MED15::TFE3 fusion renal cell carcinomas published in the literature are cystic, with three being extensively cystic. Thus, if a multilocular cystic renal neoplasm is encountered in a kidney specimen, translocation renal cell carcinoma should be included in the differential diagnosis as cystic MED15::TFE3 tRCCs carry an uncertain prognosis making recognition for future characterization necessary., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Autosomal dominant polycystic kidney disease (ADPKD) is driven by mutations in the PKD1 and PKD2 genes, and it is characterized by renal cyst formation, inflammation and fibrosis. Forkhead box protein M1 (FoxM1), a transcription factor of the Forkhead box (Fox) protein super family, has been reported to promote tumor formation, inflammation and fibrosis in many organs. However, the role and mechanism of FoxM1 in regulation of ADPKD progression is still poorly understood. Here, we show that FoxM1 is an important regulator of cyst growth in ADPKD. FoxM1 is upregulated in cyst-lining epithelial cells in Pkd1 mutant mouse kidneys and human ADPKD kidneys. FoxM1 promotes cystic renal epithelial cell proliferation by increasing the expression of Akt and Stat3 and the activation of ERK and Rb. FoxM1 also regulates cystic renal epithelial cell apoptosis through NF-κB signaling pathways. In addition, FoxM1 regulates the recruitment and retention of macrophages in Pkd1 mutant mouse kidneys, a process that is associated with FoxM1-mediated upregulation of monocyte chemotactic protein 1. Targeting FoxM1 with its specific inhibitor, FDI-6, delays cyst growth in rapidly progressing and slowly progressing Pkd1 mutant mouse kidneys. This study suggests that FoxM1 is a central and upstream regulator of ADPKD pathogenesis and provides a rationale for targeting FoxM1 as a therapeutic strategy for ADPKD treatment., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

ALG8 protein-truncating variants (PTVs) have previously been described in patients with polycystic liver disease and in some cases cystic kidney disease. Given a lack of well-controlled studies, we determined whether individuals heterozygous for ALG8 PTVs are at increased risk of cystic kidney disease in a large, unselected health system-based observational cohort linked to electronic health records in Pennsylvania (Geisinger-Regeneron DiscovEHR MyCode study). Out of 174,172 patients, 236 were identified with ALG8 PTVs. Using ICD-based outcomes, patients with these variants were significantly at increased risk of having any kidney/liver cyst diagnosis (Odds Ratio 2.42, 95% confidence interval: 1.53-3.85), cystic kidney disease (3.03, 1.26-7.31), and nephrolithiasis (1.89, 1.96-2.97). To confirm this finding, blinded radiology review of computed tomography and magnetic resonance imaging studies was completed in a matched cohort of 52 thirty-plus year old ALG8 PTV heterozygotes and related non-heterozygotes. ALG8 PTV heterozygotes were significantly more likely to have cystic kidney disease, defined as four or more kidney cysts (57.7% vs. 7.7%), or bilateral kidney cysts (69.2% vs. 15.4%), but not one or more liver cyst (11.5% vs. 7.7%). In publicly available UK Biobank data, ALG8 PTV heterozygotes were at significantly increased risk of ICD code N28 (other disorders of kidney/ureter) (3.85% vs. 1.33%). ALG8 PTVs were not associated with chronic kidney disease or kidney failure in the MyCode study or the UK Biobank data. Thus, PTVs in ALG8 result in increased risk of a mild cystic kidney disease phenotype., (Copyright © 2022 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Nephronophthisis (NPHP) is the most prevalent monogenic disease leading to end-stage renal failure in childhood. RhoA activation is involved in NPHP pathogenesis. This study explored the role of the RhoA activator guanine nucleotide exchange factor (GEF)-H1 in NPHP pathogenesis. We analyzed the expression and distribution of GEF-H1 in NPHP1 knockout ( NPHP1 KO ) mice using Western blotting and immunofluorescence, followed by GEF-H1 knockdown. Immunofluorescence and renal histology were used to examine the cysts, inflammation, and fibrosis. A RhoA GTPase activation assay and Western blotting were used to detect the expression of downstream GTP-RhoA and p-MLC2, respectively. In NPHP1 knockdown ( NPHP1 KD ) human kidney proximal tubular cells (HK2 cells), we detected the expressions of E-cadherin and α-smooth muscle actin (α-SMA). In vivo, increased expression and redistribution of GEF-H1, and higher levels of GTP-RhoA and p-MLC2 in renal tissue of NPHP1 KO mice were observed, together with renal cysts, fibrosis, and inflammation. These changes were alleviated by GEF-H1 knockdown. In vitro, the expression of GEF-H1 and activation of RhoA were also increased, with increased expression of α-SMA and decreased E-cadherin. GEF-H1 knockdown reversed these changes in NPHP1 KD HK2 cells. Thus, the GEF-H1/RhoA/MLC2 axis is activated in NPHP1 defects and may play a pivotal role in NPHP pathogenesis.

Background and Aims: Autosomal dominant polycystic liver and kidney disease is a spectrum of hereditary diseases, which display disturbed function of primary cilia leading to cyst formation. In autosomal dominant polycystic kidney disease a genetic cause can be determined in almost all cases. However, in isolated polycystic liver disease (PLD) about half of all cases remain genetically unsolved, suggesting more, so far unidentified genes to be implicated in this disease., Methods: Customized next-generation sequencing was used to identify the underlying pathogenesis in two related patients with PLD. A variant identified in SEC61A1 was further analysed in immortalized patients' urine sediment cells and in an epithelial cell model., Results: In both patients, a heterozygous missense change (c.706C>T/p.Arg236Cys) was found in SEC61A1, which encodes for a subunit of the translocation machinery of protein biosynthesis at the endoplasmic reticulum (ER). While kidney disease is absent in the proposita, her mother displays an atypical polycystic kidney phenotype with severe renal failure. In immortalized urine sediment cells, mutant SEC61A1 is expressed at reduced levels, resulting in decreased levels of polycystin-2 (PC2). In an epithelial cell culture model, we found the proteasomal degradation of mutant SEC61A1 to be increased, whereas its localization to the ER is not affected., Conclusions: Our data expand the allelic and clinical spectrum for SEC61A1, adding PLD as a new and the major phenotypic trait in the family described. We further demonstrate that mutant SEC61A1 results in enhanced proteasomal degradation and impaired biosynthesis of PC2., (© 2022 The Authors. Liver International published by John Wiley & Sons Ltd.)

Mutations or deletions in transcription factor hepatocyte nuclear factor 1 homeobox β (HNF1β) cause renal cysts and/or malformation, maturity-onset diabetes of the young and electrolyte disturbances. Here, we applied a comprehensive bioinformatic approach on ChIP-seq, RNA-seq, and gene expression array studies to identify novel transcriptional targets of HNF1β explaining the kidney phenotype of HNF1β patients. We identified BAR/IMD Domain Containing Adaptor Protein 2 Like 2 (BAIAP2L2), as a novel transcriptional target of HNF1β and validated direct transcriptional activation of the BAIAP2L2 promoter by a reporter luciferase assay. Using mass spectrometry analysis, we show that BAIAP2L2 binds to other members of the I-BAR domain-containing family: BAIAP2 and BAIAP2L1. Subsequently, the role of BAIAP2L2 in maintaining epithelial cell integrity in the kidney was assessed using Baiap2l2 knockout cell and mouse models. Kidney epithelial cells lacking functional BAIAP2L2 displayed normal F-actin distribution at cell-cell contacts and formed polarized three-dimensional spheroids with a lumen. In vivo, Baiap2l2 knockout mice displayed normal kidney and colon tissue morphology and serum and urine electrolyte concentrations were not affected. Altogether, our study is the first to characterize the function of BAIAP2L2 in the kidney in vivo and we report that mice lacking BAIAP2L2 exhibit normal electrolyte homeostasis and tissue morphology under physiological conditions., (© 2022 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Formation of branched organs requires sequential differentiation of stem cells. In this work, we find that the conducting airways derived from SOX2 + progenitors in the murine lungs fail to form without mTOR complex 1 (mTORC1) signaling and are replaced by lung cysts. Proximal-distal patterning through transitioning of distal SOX9 + progenitors to proximal SOX2 + cells is disrupted. Mitochondria number and ATP production are reduced. Compromised mitochondrial capacity results in a similar defect as that in mTORC1-deficient lungs. This suggests that mTORC1 promotes differentiation of SOX9 + progenitors to form the conducting airways by modulating mitochondrial capacity. Surprisingly, in all mutants, saccules are produced from lung cysts at the proper developmental time despite defective branching. SOX9 + progenitors also differentiate into alveolar epithelial type I and type II cells within saccules. These findings highlight selective utilization of energy and regulatory programs during stem cell differentiation to produce distinct structures of the mammalian lungs., (© 2022. The Author(s).)

Polycystic kidney disease (PKD) is characterized by the formation and progressive enlargement of fluid-filled cysts due to abnormal cell proliferation. Cyclic AMP agonists, including arginine vasopressin, stimulate ERK-dependent proliferation of cystic cells, but not normal kidney cells. Previously, B-Raf proto-oncogene (BRAF), a MAPK kinase kinase that activates MEK-ERK signaling, was shown to be a central intermediate in the cAMP mitogenic response. However, the role of BRAF on cyst formation and enlargement in vivo had not been demonstrated. To determine if active BRAF induces kidney cyst formation, we generated transgenic mice that conditionally express BRAF V600E , a common activating mutation, and bred them with Pkhd1-Cre mice to express active BRAF in the collecting ducts, a predominant site for cyst formation. Collecting duct expression of BRAFV600E (BRaf CD ) caused kidney cyst formation as early as three weeks of age. There were increased levels of phosphorylated ERK (p-ERK) and proliferating cell nuclear antigen, a marker for cell proliferation. BRaf CD mice developed extensive kidney fibrosis and elevated blood urea nitrogen, indicating a decline in kidney function, by ten weeks of age. BRAF V600E transgenic mice were also bred to Pkd1 RC/RC and pcy/pcy mice, well-characterized slowly progressive PKD models. Collecting duct expression of active BRAF markedly increased kidney weight/body weight, cyst number and size, and total cystic area. There were increased p-ERK levels and proliferating cells, immune cell infiltration, interstitial fibrosis, and a decline in kidney function in both these models. Thus, our findings demonstrate that active BRAF is sufficient to induce kidney cyst formation in normal mice and accelerate cystic disease in PKD mice., (Copyright © 2022 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Hepatic cysts are fluid-filled lesions in the liver that are estimated to occur in 5% of the population. They may cause hepatomegaly and abdominal pain. Progression to secondary fibrosis, cirrhosis, or cholangiocarcinoma can lead to morbidity and mortality. Previous studies of patients and rodent models have associated hepatic cyst formation with increased proliferation and fluid secretion in cholangiocytes, which are partially due to impaired primary cilia. Congenital hepatic cysts are thought to originate from faulty bile duct development, but the underlying mechanisms are not fully understood. In a forward genetic screen, we identified a zebrafish mutant that developed hepatic cysts during larval stages. The cyst formation was not due to changes in biliary cell proliferation, bile secretion, or impairment of primary cilia. Instead, time-lapse live imaging data showed that the mutant biliary cells failed to form interconnecting bile ducts because of defects in motility and protrusive activity. Accordingly, immunostaining revealed a disorganized actin and microtubule cytoskeleton in the mutant biliary cells. By whole-genome sequencing, we determined that the cystic phenotype in the mutant was caused by a missense mutation in the furinb gene, which encodes a proprotein convertase. The mutation altered Furinb localization and caused endoplasmic reticulum (ER) stress. The cystic phenotype could be suppressed by treatment with the ER stress inhibitor 4-phenylbutyric acid and exacerbated by treatment with the ER stress inducer tunicamycin. The mutant liver also exhibited increased mammalian target of rapamycin (mTOR) signaling. Treatment with mTOR inhibitors halted cyst formation at least partially through reducing ER stress. Conclusion: Our study has established a vertebrate model for studying hepatic cystogenesis and illustrated the contribution of ER stress in the disease pathogenesis., (© 2022 The Authors. Hepatology Communications published by Wiley Periodicals LLC on behalf of American Association for the Study of Liver Diseases.)

Polycystic liver disease (PLD) is a genetic disorder in which patients suffer from progressive development of multiple (>10) hepatic cysts. Most patients remain asymptomatic during the course of their disease. However, a minority of PLD patients suffer from symptoms caused by hepatomegaly leading to serious limitations in daily life. Untreated symptomatic PLD patients score significantly worse on health-related quality of life (HRQoL) compared to age and gender-matched populations. Currently, liver transplantation is the only curative treatment for PLD. The main goal of other available therapies is to strive for symptomatic relief and improvement of HRQoL by suppressing disease progression. In this review, we summarize the effect of PLD treatment on patient-reported outcome measures with a distinction between HRQoL and symptom severity. At present there is heterogeneity in application of questionnaires and no questionnaire is available that measures both HRQoL and PLD symptom severity. Therefore, we recommend the combination of a validated PLD-specific symptom severity questionnaire and a general HRQoL questionnaire to evaluate treatment success as a minimal core set. However, the specific choice of questionnaires depends on treatment choice and/or research question. These questionnaires may serve as a biomarker of treatment response, failure, and adverse events., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc.)

Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic disorder characterized by the formation of kidney cysts that originate from the epithelial tubules of the nephron and primarily results from mutations in polycystin-1 ( PKD1 ) and polycystin-2 ( PKD2 ). The metanephric organ culture (MOC) is an ex vivo system in which explanted embryonic kidneys undergo tubular differentiation and kidney development. MOC has been previously used to study polycystic kidney disease as treatment with 8-bromo-cAMP induces the formation of kidney cysts. However, the inefficiency of manipulating gene expression in MOC has limited its utility for identifying genes and pathways that are involved in cystogenesis. Here, we used a lentivirus and three serotypes of self-complementary adeno-associated viral (scAAV) plasmids that express green fluorescent protein and found that scAAV serotype D/J transduces the epithelial compartment of MOC at an efficiency of 68%. We used scAAV/DJ to deliver shRNA to knockdown Pvt1 , a long noncoding RNA, which was upregulated in kidneys from Pkd1 and Pkd2 mutant mice and humans with ADPKD. shRNA delivery by scAAV/DJ downregulated expression of Pvt1 by 45% and reduced the cyst index by 53% in wild-type MOCs and 32% in Pkd1 -null MOCs. Knockdown of Pvt1 decreased the level of c-MYC protein by 60% without affecting Myc mRNA, indicating that Pvt1 regulation of c-MYC was posttranscriptional. These results identify Pvt1 as a long noncoding RNA that modulates cyst progression in MOC. NEW & NOTEWORTHY This study identified scAAV/DJ as effective in transducing epithelial cells of the metanephric organ culture (MOC). We used scAAV/DJ shRNA to knockdown Pvt1 in cystic MOCs derived from Pkd1 -null embryos. Downregulation of Pvt1 reduced cyst growth and decreased levels of c-MYC protein. These data suggest that suppression of Pvt1 activity in autosomal dominant polycystic kidney disease might reduce cyst growth.

Background: Emerging evidence indicates that epigenetic modulation of gene expression plays a key role in the progression of autosomal dominant polycystic kidney disease (ADPKD). However, the molecular basis for how the altered epigenome modulates transcriptional responses, and thereby disease progression in ADPKD, remains largely unknown., Methods: Kidneys from control and ADPKD mice were examined for the expression of CDYL and histone acylations. CDYL expression and its correlation with disease severity were analyzed in a cohort of patients with ADPKD. Cdyl transgenic mice were crossed with Pkd1 knockout mice to explore CDYL's role in ADPKD progression. Integrated cistromic and transcriptomic analyses were performed to identify direct CDYL target genes. High-sensitivity mass spectrometry analyses were undertaken to characterize CDYL-regulated histone lysine crotonylations (Kcr). Biochemical analysis and zebrafish models were used for investigating CDYL phase separation., Results: CDYL was downregulated in ADPKD kidneys, accompanied by an increase of histone Kcr. Genetic overexpression of Cdyl reduced histone Kcr and slowed cyst growth. We identified CDYL-regulated cyst-associated genes, whose downregulation depended on CDYL-mediated suppression of histone Kcr. CDYL assembled nuclear condensates through liquid-liquid phase separation in cultured kidney epithelial cells and in normal kidney tissues. The phase-separating capacity of CDYL was required for efficient suppression of locus-specific histone Kcr, of expression of its target genes, and of cyst growth., Conclusions: These results elucidate a mechanism by which CDYL nuclear condensation links histone Kcr to transcriptional responses and cystogenesis in ADPKD., (Copyright © 2022 by the American Society of Nephrology.)

Autosomal dominant polycystic kidney disease (ADPKD), among the most common human genetic conditions and a frequent etiology of kidney failure, is primarily caused by heterozygous PKD1 mutations. Kidney cyst formation occurs when PKD1 dosage falls below a critical threshold. However, no framework exists to harness the remaining allele or reverse PKD1 decline. Here, we show that mRNAs produced by the noninactivated PKD1 allele are repressed via their 3'-UTR miR-17 binding element. Eliminating this motif (Pkd1 ∆17 ) improves mRNA stability, raises Polycystin-1 levels, and alleviates cyst growth in cellular, ex vivo, and mouse PKD models. Remarkably, Pkd2 is also inhibited via its 3'-UTR miR-17 motif, and Pkd2 ∆17 -induced Polycystin-2 derepression retards cyst growth in Pkd1-mutant models. Moreover, acutely blocking Pkd1/2 cis-inhibition, including after cyst onset, attenuates murine PKD. Finally, modeling PKD1 ∆17 or PKD2 ∆17 alleles in patient-derived primary ADPKD cultures leads to smaller cysts, reduced proliferation, lower pCreb1 expression, and improved mitochondrial membrane potential. Thus, evading 3'-UTR cis-interference and enhancing PKD1/2 mRNA translation is a potentially mutation-agnostic ADPKD-arresting approach., (© 2022. The Author(s).)

Disorders of the autosomal dominant polycystic kidney disease (ADPKD) spectrum are characterized by the development of kidney cysts and progressive kidney function decline. PKD1 and PKD2, encoding polycystin (PC)1 and 2, are the two major genes associated with ADPKD; other genes include IFT140, GANAB, DNAJB11, and ALG9. Genetic testing remains inconclusive in ∼7% of the families. We performed whole-exome sequencing in a large multiplex genetically unresolved (GUR) family affected by ADPKD-like symptoms and identified a monoallelic frameshift variant (c.703&#95;704delCA) in ALG5. ALG5 encodes an endoplasmic-reticulum-resident enzyme required for addition of glucose molecules to the assembling N-glycan precursors. To identify additional families, we screened a cohort of 1,213 families with ADPKD-like and/or autosomal-dominant tubulointerstitial kidney diseases (ADTKD), GUR (n = 137) or naive to genetic testing (n = 1,076), by targeted massively parallel sequencing, and we accessed Genomics England 100,000 Genomes Project data. Four additional families with pathogenic variants in ALG5 were identified. Clinical presentation was consistent in the 23 affected members, with non-enlarged cystic kidneys and few or no liver cysts; 8 subjects reached end-stage kidney disease from 62 to 91 years of age. We demonstrate that ALG5 haploinsufficiency is sufficient to alter the synthesis of the N-glycan chain in renal epithelial cells. We also show that ALG5 is required for PC1 maturation and membrane and ciliary localization and that heterozygous loss of ALG5 affects PC1 maturation. Overall, our results indicate that monoallelic variants of ALG5 lead to a disorder of the ADPKD-spectrum characterized by multiple small kidney cysts, progressive interstitial fibrosis, and kidney function decline., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Despite the known critical regulatory functions of microRNAs, histone modifications, and DNA methylation in reprograming plant epigenomes in response to pathogen infection, the molecular mechanisms underlying the tight coordination of these components remain poorly understood. Here, we show how Arabidopsis (Arabidopsis thaliana) miR778 coordinately modulates the root transcriptome, histone methylation, and DNA methylation via post-transcriptional regulation of the H3K9 methyltransferases SU(var)3-9 homolog 5 (SUVH5) and SUVH6 upon infection by the beet cyst nematode Heterodera schachtii. miR778 post-transcriptionally silences SUVH5 and SUVH6 upon nematode infection. Manipulation of the expression of miR778 and its two target genes significantly altered plant susceptibility to H. schachtii. RNA-seq analysis revealed a key role of SUVH5 and SUVH6 in reprograming the transcriptome of Arabidopsis roots upon H. schachtii infection. In addition, chromatin immunoprecipitation (ChIP)-seq analysis established SUVH5 and SUVH6 as the main enzymes mediating H3K9me2 deposition in Arabidopsis roots in response to nematode infection. ChIP-seq analysis also showed that these methyltransferases possess distinct DNA binding preferences in that they are targeting transposable elements under noninfected conditions and protein-coding genes in infected plants. Further analyses indicated that H3K9me2 deposition directed by SUVH5 and SUVH6 contributes to gene expression changes both in roots and in nematode feeding sites and preferentially associates with CG DNA methylation. Together, our results uncovered multi-layered epigenetic regulatory mechanisms coordinated by miR778 during Arabidopsis-H. schachtii interactions., (© American Society of Plant Biologists 2022. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Mouse germline cysts, on average, develop into six oocytes supported by 24 nurse cells that transfer cytoplasm and organelles to generate a Balbiani body. We showed that between E14.5 and P5, cysts periodically activate some nurse cells to begin cytoplasmic transfer, which causes them to shrink and turnover within 2 days. Nurse cells die by a programmed cell death (PCD) pathway involving acidification, similar to Drosophila nurse cells, and only infrequently by apoptosis. Prior to initiating transfer, nurse cells co-cluster by scRNA-seq with their pro-oocyte sisters, but during their final 2 days, they cluster separately. The genes promoting oocyte development and nurse cell PCD are upregulated, whereas the genes that repress transfer, such as Tex14, and oocyte factors, such as Nobox and Lhx8, are under-expressed. The transferred nurse cell centrosomes build a cytocentrum that establishes a large microtubule aster in the primordial oocyte that organizes the Balbiani body, defining the earliest oocyte polarity., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Birt-Hogg-Dubé (BHD) syndrome is an ultrarare lung disease with unclear prevalence and incidence. Our study aimed to identify the epidemiological and clinical features of BHD syndrome by using nationwide claims data from the Korean Health Insurance Review and Assessment service., Methods: Patients with BHD syndrome who had the following criteria were included: 1) tested for folliculin gene mutation, and 2) had at least one of the conditions: other specified malformation syndromes, fibrofolliculoma, acrochordon, lung cyst, cancer, and pneumothorax based on International Classification of Disease-10 code., Results: We found 26 patients with BHD syndrome from 2017 to 2019. The prevalence of BHD syndrome was 5.67 per 107 population, with no peak age. Among incidence cases, the median age of diagnosis was 51 years, with slightly more females than males (n = 15, 57.7%). Over half of the patients (n = 14, 53.8%) experienced pneumothorax, and 10 (38.5%) developed malignant neoplasm within the clinical course., Conclusions: The prevalence of BHD syndrome in Korea is extremely low. However, affected patients manifest several comorbidities, including malignant neoplasm and repetitive pneumothorax., Competing Interests: The authors have declared that no competing interests exist.