Search

Background: The epidemic of COVID-19 presents a special threat to older adults. However, information on kidney damage in older patients with COVID-19 is limited. Acute kidney injury (AKI) is common in hospitalized adults and associated with poor prognosis. We sought to explore the association between AKI and mortality in older patients with COVID-19. Methods: We conducted a retrospective, observational cohort study in a large tertiary care university hospital in Wuhan, China. All consecutive inpatients older than 65 years with COVID-19 were enrolled in this cohort. Demographic data, laboratory values, comorbidities, treatments, and clinical outcomes were all collected. Data were compared between patients with AKI and without AKI. The association between AKI and mortality was analyzed. Results: Of 1764 in-hospital patients, 882 older adult cases were included in this cohort. The median age was 71 years (interquartile range: 68–77), 440 (49.9%) were men. The most presented comorbidity was cardiovascular diseases (58.2%), followed by diabetes (31.4%). Of 882 older patients, 115 (13%) developed AKI and 128 (14.5%) died. Patients with AKI had higher mortality than those without AKI (68 [59.1%] vs 60 [7.8%]; p < .001). Multivariable Cox regression analysis showed that increasing odds of in-hospital mortality are associated with higher interleukin-6 on admission, myocardial injury, and AKI. Conclusions: Acute kidney injury is not an uncommon complication in older patients with COVID-19 but is associated with a high risk of death. Physicians should be aware of the risk of AKI in older patients with COVID-19. [ABSTRACT FROM AUTHOR]

Species are fundamental units in biological research and can be defined on the basis of various operational criteria. There has been growing use of molecular approaches for species delimitation. Among the most widely used methods, the generalized mixed Yule-coalescent (GMYC) and Poisson tree processes (PTP) were designed for the analysis of single-locus data but are often applied to concatenations of multilocus data. In contrast, the Bayesian multispecies coalescent approach in the software Bayesian Phylogenetics and Phylogeography (BPP) explicitly models the evolution of multilocus data. In this study, we compare the performance of GMYC, PTP, and BPP using synthetic data generated by simulation under various speciation scenarios. We show that in the absence of gene flow, the main factor influencing the performance of these methods is the ratio of population size to divergence time, while number of loci and sample size per species have smaller effects. Given appropriate priors and correct guide trees, BPP shows lower rates of species overestimation and underestimation, and is generally robust to various potential confounding factors except high levels of gene flow. The single-threshold GMYC and the best strategy that we identified in PTP generally perform well for scenarios involving more than a single putative species when gene flow is absent, but PTP outperforms GMYC when fewer species are involved. Both methods are more sensitive than BPP to the effects of gene flow and potential confounding factors. Case studies of bears and bees further validate some of the findings from our simulation study, and reveal the importance of using an informed starting point for molecular species delimitation. Our results highlight the key factors affecting the performance of molecular species delimitation, with potential benefits for using these methods within an integrative taxonomic framework. [ABSTRACT FROM AUTHOR]

Households in Xuanwei and Fuyuan, China, possess hazardous levels of fine particulate matter with an aerodynamic diameter <2.5 microns (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) from coal combustion. Previous studies found that increased exposure to PM2.5 and benzo[a]pyrene (BaP; a PAH) were associated with decreased mitochondrial DNA copy number (mtDNAcn), a marker of oxidative stress. We further evaluated these associations in a cross-sectional study of 148 healthy non-smoking women from Xuanwei and Fuyuan. Personal exposure to PM2.5 and BaP was measured using portable devices. MtDNAcn was measured using qPCR amplification of leukocyte DNA that was collected after air measurements. Linear regression models were used to estimate the associations between personal exposure to PM2.5 and BaP, and mtDNAcn adjusted for age, body mass index (BMI) and fuel type. We found inverse associations between exposure to PM2.5 and BaP, and mtDNAcn. Each incremental log-µg/m3 increase in PM2.5 was associated with a significant decrease in mtDNAcn of -10.3 copies per cell [95% confidence interval (95% CI): -18.6, -2.0; P = 0.02]. Additionally, each log-ng/m3 increase in BaP was associated with a significant decrease in mtDNAcn of -5.4 copies per cell (95% CI: -9.9, -0.8, P = 0.02). Age, BMI, fuel type and coal mine type were not significantly associated with mtDNAcn. Exposure to PM2.5 and BaP may alter mitochondrial dynamics in non-smoking Chinese women. MtDNAcn may be a potential mediator of indoor air pollution on chronic disease development. [ABSTRACT FROM AUTHOR]

Statins have been reported to induce tendinopathy and even tendon rupture. The present study was designed to investigate the potential molecular mechanism underlying the adverse effect of simvastatin on tendon cells. An in vitro tendon healing model was performed using tendon cells isolated from rat Achilles tendons. The viability of tendon cells and cell cycle progression were examined by the MTT assay and flow cytometric analysis, respectively. Immunofluorescent staining for Ki-67 was used to assess the proliferation activity of tendon cells. Western blot analysis and coimmunoprecipitation was used to determine the protein expression of cell cycle-related proteins. To investigate the potential mechanism underlying the effect of statins on tendon cells, mevalonate, farnesyl pyrophosphate (FPP), or geranylgeranyl pyrophosphate (GGPP) was added to simvastatin-treated tendon cells. Simvastatin inhibited the in vitro tendon healing model and tendon cell proliferation in a dose-dependent manner. Immunofluorescent staining demonstrated reduced ki-67 expression in simvastatin-treated tendon cells. Furthermore, simvastatin induced cell cycle arrest at the G1 phase. The expression levels of cdk1, cdk2, cyclin A, and cyclin E were downregulated by simvastatin in a dose-dependent manner. The inhibitory effect of simvastatin was proved to mediate the reduction of mevalonate, and the addition of exogenous GGPP completely prevented the inhibitory effect of simvastatin on tendon cells. The present study demonstrated, for the first time, the molecular mechanism underlying simvastatin-induced tendinopathy or tendon rupture. GGPP was shown to prevent the adverse effect of simvastatin in tendon cells without interfering with its cholesterol-reducing efficacy. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA) is vulnerable to mutations, and the number of copies of mtDNA per cell may increase to compensate for DNA damage. Case–control studies have reported associations between altered mtDNA copy number and risk of renal cell carcinoma (RCC); however, this association has not been investigated prospectively. We conducted a nested case–control study (252 cases and 504 controls) of RCC risk in relation to pre-diagnostic leukocyte mtDNA copy number in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. mtDNA copy number was measured in triplicate using a fluorescence-based quantitative PCR assay; samples from 22 cases and 36 controls could not be assayed, leaving 230 cases and 468 controls for analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. High mtDNA copy number was associated with an increased risk of RCC, both overall (highest quartile versus lowest: OR = 2.0, 95% CI = 1.2–3.2; Ptrend = 0.002) and among cases diagnosed ≥6 years after blood collection (OR = 2.6, 95% CI = 1.4–5.0; Ptrend = 0.003). These findings did not differ significantly by sex, body mass index, history of hypertension or smoking status (Pinteraction ≥ 0.3). Results of this study suggest that high pre-diagnostic leukocyte mtDNA copy number, a suspected marker of oxidative DNA damage and mitochondrial dysfunction, is associated with increased future RCC risk. [ABSTRACT FROM AUTHOR]

The host cellular environment is a key determinant of pathogen infectivity. Viral gene expression and viral particle production of glucose-6-phosphate dehydrogenase (G6PD)-deficient and G6PD-knockdown cells were much higher than their counterparts when human coronavirus (HCoV) 229E was applied at 0.1 multiplicity of infection. These phenomena were correlated with increased oxidant production. Accordingly, ectopic expression of G6PD in G6PD-deficient cells or addition of antioxidant (such as α-lipoic acid) to G6PD-knockdown cells attenuated the increased susceptibility to HCoV229E infection. All experimental data indicated that oxidative stress in host cells is an important factor in HCoV229E infectivity. [ABSTRACT FROM AUTHOR]

Background: We previously identified DnaJ-like heat shock protein (HLJ1) as a gene associated with tumor invasion. Here, we investigated the clinical significance of HLJ1 expression in non-small-cell lung cancer (NSCLC) patients and its role in cancer progression. Methods: We induced HLJI overexpression or knockdown in human lung adenocarcinoma CL1-5 cells and analyzed cell proliferation, anchorage-independent growth, in vivo tumorigenesis, cell motility, invasion, and cell cycle progression. Expression of genes that act downstream of HLJ1 was examined by DNA microarray analysis, pathway analysis, and western blotting. We measured HLJ1 expression in tumors and adjacent normal tissues of 71 NSCLC patients by quantitative reverse transcription-polymerase chain reaction. Associations between HLJ1 expression and disease-free and overall survival were determined using the log-rank test and multivariable Cox proportional hazards regression analysis. Validation was performed in an independent cohort of 56 NSCLC patients. Loss of heterozygosity (LOH) mapping of the HLJ1 locus was analyzed in 48 paired microdissected NSCLC tumors. All statistical tests were two-sided. Results: HLJ1 expression inhibited lung cancer cell proliferation, anchorage- independent growth, tumorigenesis, cell motility, and invasion, and slowed cell cycle progression through a novel STAT1/p21WAF1 pathway that is independent of P53 and interferon. HLJ1 expression was lower in tumors than in adjacent normal tissue in 55 of 71 patients studied. NSCLC patients with high HLJ1 expressing tumors had reduced cancer recurrence (hazard ratio [HR] = 0.47; 95% confidence interval [CI] = 0.23 to 0.93; P = .03) and longer overall survival (HR = 0.38; 95% CI = 0.16 to 0.89; P = .03) than those with low-expressing tumors. Validation in the independent patient cohort confirmed the association between HLJ1 expression and patient outcome. LOH mapping revealed high frequencies (66.7% and 70.8%) of allelic loss and microsatellite instability (87.5% and 95.2%) of the HLJ1 locus at chromosome 1p31.1. Conclusions: HLJ1 is a novel tumor suppressor in NSCLC, and high HLJ1 expression is associated with reduced cancer recurrence and prolonged survival of NSCLC patients. [ABSTRACT FROM AUTHOR]

Subcellular localization of calcium in apical bud cells of mulberry (Morus bombciz Koidz) was investigated by a combination of calcium antimonate precipitation and electron microscopy (EM), over a 10-month period extending from July to May. Calcium antimonate deposits, an indication of Ca2+ localization, were found mainly in the intercellular spaces and vacuoles of tissues collected in summer (e.g., July 10). Few deposits were seen in the cytosol and the nucleus, indicating that when plants were actively growing, the cytoplasm had a low concentration of Ca2+. As the day length became shorter (e.g., August 8), Ca2+ deposits increased in the cytosol and the nucleus. When plant dormancy and cold hardiness were rapidly developing in September and October, a large number of Ca2+ deposits were seen in the cytoplasm and the nucleus, where they remained for about 60 days. Tissue samples collected during midwinter (e.g., January 20) displayed few Ca2+ deposits in the cytoplasm and the nucleus compared with the sample collected on November 1. The number of Ca2+ deposits remained low even when day length increased in the spring (e.g., May 5). We conclude that the seasonal dynamics of intracellular Ca2+ concentration bear a close relationship with growth cessation and the development of dormancy and cold hardiness in temperate woody perennials. [ABSTRACT FROM PUBLISHER]

Electron microscopic observations revealed that electron-dense antimonate Ca2+ deposits were mostly localized in the vacuole and the intercellular space in both maize and winter wheat when their seedlings were grown at 25°C. The reaction products—cerium phosphate deposits of Ca2+- ATPase activity were mainly seen at the cytoplasmic side of the plasma membrane. Few cerium phosphate deposits also were observed on the nuclear envelope. In both species, after 1 or 3 h 2°C chilling, antimonate Ca2+ deposits increased in the cytosol and the nucleus, but cerium phosphate deposits showed no visible difference compared to their corresponding 25°C seedlings. After 12, 24, or 72 h chilling, maize seedlings still maintained a high level of antimonate Ca2+ deposits in the cytosol and the nucleus. During these periods, maize Ca2+-ATPase, as indicated by the number of cerium phosphate deposits, became less and less active as chilling proceeded. In winter wheat, the increased cytosolic and nuclear antimonate Ca2+ deposits were restored to a low resting level after 12, 24, or 72 h chilling, while the Ca2+-ATPase was maintained active, contrary to maize scenario. The transient cytosolic and nuclear Ca2+ increase and the activities of Ca2+-ATPase during chilling are discussed in relation to plant chilling injury and cold acclimation. [ABSTRACT FROM AUTHOR]

In poplar (Populus deltoides Bartr. ex Marsh), bud dormancy and freezing tolerance were concomitantly induced by short-day (SD) photoperiods. Ultrastructural changes and the alteration in subcellular localization of calcium in apical bud cells associated with dormancy development were investigated. During the development of dormancy, the thickness of cell walls increased significantly, the number of starch granules increased, and there was a significant accumulation of storage proteins in the vacuoles of the apical bud cells. The most striking change was the constriction and blockage of the plasmodesmata.It was demonstrated that antimonate precipitation is a reliable technique for studying subcellular localization of calcium in poplar apical bud cells. Under the long day (LD) photoperiod, electron-dense calcium antimonate precipitates were mainly localized in vacuoles, intercellular spaces and plastids. Some antimonate precipitates were also found in the cell walls and at the entrance of the plasmodesmata. However, there were few Ca2+ deposits found in the cytosol and nucleus. After 20 d of SD exposure, when development of bud dormancy was initiated, calcium deposits in intercellular spaces were decreased, whereas some deposits were found in the cytosol and nuclei. From 28–49 d of SD exposure, while dormancy was developing, a large number of Ca2+ precipitates were found in the cytosol and nuclei. When deep dormancy was reached after 77 d of SD exposure, Ca2+ deposits became fewer in both cytosol and nuclei, whereas numerous deposits were again observed in the cell walls and in the intercellular spaces. These results suggest that under the influence of SD photoperiods, there are alterations in subcellular Ca2+ localization, and changes in ultrastructure of apical bud cells during the development of dormancy. The constriction and blockage of plasmodesmata may cause the cessation of symplastic transport, limit cellular communication and signal transduction between adjacent cells, which in turn may lead to events associated with growth cessation and dormancy development in buds. [ABSTRACT FROM AUTHOR]

XRCC4 is a generally expressed protein of 334 amino acids that is involved in the repair of DNA double-strand breaks and in V(D)J recombination, but its function is unknown. In this study, we have used a mutational approach and the yeast two-hybrid method to perform an initial characterization of this protein. We show that the XRCC4 protein is located in the nucleus. We also demonstrate that several potential phosphorylation sites are not required for XRCC4 function in a transient V(D)J recombination assay. In addition, we show that XRCC4 forms a homodimer in vivo with the homodimerization domain being located within amino acids 115–204. Finally, we define a core domain of XRCC4 that functions in V(D)J recombination and comprises amino acids 18–204. Potential functions of XRCC4 are discussed. [ABSTRACT FROM AUTHOR]

Mitochondria are eukaryotic organelles responsible for energy production. Mitochondrial DNA (mtDNA) lack introns and protective histones, have limited DNA repair capacity and compensate for damage by increasing the number of mtDNA copies. As a consequence, mitochondria are more susceptible to reactive oxygen species, an important determinant of cancer risk, and it is hypothesized that increased mtDNA copy number may be associated with carcinogenesis. We assessed the association of mtDNA copy number and lung cancer risk in 227 prospectively collected cases and 227 matched controls from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for age at randomization, smoking years and number of cigarettes smoked per day. There was suggestion of a dose-dependent relationship between mtDNA copy number and subsequent risk of lung cancer, with a prominent effect observed in the highest mtDNA copy number quartile [ORs (95% CI) by quartile: 1.0 (reference), 1.3 (0.7–2.5), 1.1 (0.6–2.2) and 2.4 (1.1–5.1); Ptrend = 0.008]. This is the first report, to the best of our knowledge, to suggest that mtDNA copy number may be positively associated with subsequent risk of lung cancer in a prospective cohort study; however, replication is needed in other studies and populations. [ABSTRACT FROM PUBLISHER]

Filamins are highly conserved actin-crosslinking proteins that regulate organization of the actin cytoskeleton. As key components of versatile signaling scaffolds, filamins are implicated in developmental anomalies and cancer. Multiple isoforms of filamins exist, raising the possibility of distinct functions for each isoform during development and in disease. Here, we provide an initial characterization of jitterbug (jbug), which encodes one of the two filamin-type proteins in Drosophila. We generate Jbug antiserum that recognizes all of the spliced forms and reveals differential expression of different Jbug isoforms during development, and a significant maternal contribution of Jbug protein. To reveal the function of Jbug isoforms, we create new genetic tools, including a null allele that deletes all isoforms, hypomorphic alleles that affect only a subset, and UAS lines for Gal4-driven expression of the major isoforms. Using these tools, we demonstrate that Jbug is required for viability and that specific isoforms are required in the formation of actin-rich protrusions including thoracic bristles in adults and ventral denticles in the embryo. We also show that specific isoforms of Jbug show differential localization within epithelia and that maternal and zygotic loss of jbug disrupts Crumbs (Crb) localization in several epithelial cell types. [ABSTRACT FROM AUTHOR]

CTP synthase (CTPsyn) plays an essential role in DNA, RNA, and lipid synthesis. Recent studies in bacteria, yeast, and Drosophila all reveal a polymeric CTPsyn structure, which dynamically regulates its enzymatic activity. However, the molecular mechanism underlying the formation of CTPsyn polymers is not completely understood. In this study, we found that reversible ubiquitination regulates the dynamic assembly of the filamentous structures of Drosophila CTPsyn. We further determined that the proto-oncogene Cbl, an E3 ubiquitin ligase, controls CTPsyn filament formation in endocycles. While the E3 ligase activity of Cbl is required for CTPsyn filament formation, Cbl does not affect the protein levels of CTPsyn. It remains unclear whether the regulation of CTPsyn filaments by Cbl is through direct ubiquitination of CTPsyn. In the absence of Cbl or with knockdown of CTPsyn, the progression of the endocycle-associated S phase was impaired. Furthermore, overexpression of wild-type, but not enzymatically inactive CTPsyn, rescued the endocycle defect in Cbl mutant cells. Together, these results suggest that Cbl influences the nucleotide pool balance and controls CTPsyn filament formation in endocycles. This study links Cbl-mediated ubiquitination to the polymerization of a metabolic enzyme and reveals a role for Cbl in endocycles during Drosophila development. [ABSTRACT FROM AUTHOR]