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Abstract Background According to the 2016–2017 Tanzania HIV Impact Survey, only 45% of men living with HIV (MLWH) were aware of their HIV status. In an effort to increase HIV testing in Tanzania, including among men, the Government of Tanzania passed a law in December 2019 allowing HIV self-testing (HIVST) to be included in the national testing strategies. The objective of this paper is to describe the development and pilot feasibility assessment of the Self-Testing Education and Promotion (STEP) intervention, which includes male peer education and demand creation for HIVST, and nurse-led distribution of HIVST kits in a community setting. Methods The development and piloting processes were guided by the ADAPT-ITT model and informed by a national PEPFAR/USAID-funded HIV implementation science project called Sauti. The adapted STEP intervention included the following two components: 1) peer-based HIVST promotion; and 2) nurse-led HIVST distribution. For the feasibility assessment, 25 men were selected and trained as peer educators in 2019 to promote HIVST among their peers before recruiting 253 men who received instructions and an HIVST kit from a nurse at a community-based study tent site. Results Of the 236 participants who completed the 1-month follow-up survey, 98.3% reported using the kit. The majority (92.4%) of participants reported a negative HIVST result while 4.2% (n = 10) received a positive result. Most (70%, n = 7) of the participants with a positive result sought follow-up services at a healthcare facility while 40.3% (n = 95) of the participants with a negative self-test result visited the community-based project site. Most of the men (53%, n = 129) did not visit a healthcare facility or the study site. Conclusion The findings demonstrate that the combined peer-based promotion and nurse-led distribution of HIVST intervention was acceptable and feasible, though seeking follow-up services at healthcare facilities remained low. Future research should evaluate the effectiveness of offering nurse-led community-based clinical follow-up services in addition to HIVST rather than referral to facilities.

Abstract Background Digital health interventions have the potential to improve linkage to care after HIV self-testing (HIVST). This study aimed to understand clients’ and providers’ perceptions of benefits, and barriers of a digital health intervention designed to improve linkage to care after HIV self-testing in Tanzania. Methods This exploratory qualitative research study was conducted in Hai and Moshi, districts in Kilimanjaro region, Tanzania. Four health facilities were selected based on their involvement in an HIVST pilot program implemented by Elizabeth Glassier Pediatric AIDS Foundation (EGPAF) Tanzania through the USAID funded program. The study included female index clients and their partners, and healthcare providers at the healthcare facilities. We used a semi-structured interview guide with open-ended questions for data collection. Data collection was conducted from 16th January 2023 to 3rd February 2023. Thematic analysis of the qualitative data was conducted, guided by the Health Belief Model (HBM), and results were developed in collaboration with the community partners. Results A total of 42 participants were included in the study, comprising 9 male clients, 17 female index clients, and 16 health care workers (HCWs) (4 male and 12 female) who were involved in delivering HIVST services. The study’s findings revealed mixed feelings about the use of a digital health intervention. Majority of participants perceived digital health as a valuable intervention for enhancing linkage to care, improved health outcomes, improved communication with healthcare workers, and increased privacy. Therefore, they supported scale-up of a digital health intervention. Participants also expressed that the potential benefits of a digital health intervention include the convenience of accessing healthcare services from the comfort of their homes or any location. However, a few participants expressed concerns about potential risks associated with sending health-related text messages. They feared that recipients might not be in a safe space, leading to stigma and avoidance of engagement. A few female participants expressed concerns about confidentiality breaches, particularly regarding shared phones with family or friends. Fear of being judged or misunderstood by others could deter them from reading or acting upon these messages. Most participants recommended tailored strategies that prioritize confidentiality and trust. Recognizing these psychological aspects is vital for customizing digital health interventions to effectively address participants’ concerns. Conclusions Digital health interventions may improve the linkage of HIV self-testers to care. Recommendations include personalized and culturally relevant communication and technical accessibility to make interventions effective and inclusive. This study provides valuable insights for designing patient-centered interventions for HIV care and treatment.

Objective: The global burden of HIV remains a critical public health challenge, particularly in sub-Saharan Africa, home to over two-thirds of individuals living with HIV. HIV self-testing (HIVST) has emerged as a promising strategy endorsed by the World Health Organization to achieve UNAIDS targets. Despite its potential, challenges persist in linking self-testers to care post a positive result. Digital health interventions, including chatbots and mobile applications, offer innovative solutions to address this gap. However, a comprehensive bibliometric analysis of the collaboration and growth in the literature at the intersection of HIVST and digital interventions is lacking.Methods: The study employs a bibliometric approach, leveraging data from the Web of Science, to analyze the characteristics, citation pattern and content of 289 articles spanning 1992–2023. The analysis involves performance assessment, scientific collaboration analysis, science mapping, and content analysis. Key bibliometric indicators, such as annual growth rate, citation impact, and authorship patterns, are explored. Collaboration patterns among countries, institutions, and authors are elucidated, and thematic mapping provides insight into the key research themes.Results: The analysis reveals a dynamic and expanding field, with an annual scientific growth rate of 12.25%. Notable contributions come from diverse sources, including North America, Europe, and Africa. High-impact journals such as JMIR mHealth and uHealth play a crucial role in disseminating research findings. African authors, including Lebelonyane R, Ford N, and Lockman S, feature prominently, reflecting a positive trend in diverse authorship. Co-citation analysis highlights influential manuscripts, with systematic reviews dominating the top-cited articles. Collaboration analysis underscores strategic partnerships globally, particularly involving the United States, Australia, South Africa, and the United Kingdom.Conclusion: This bibliometrics analysis provides a comprehensive overview of the digital health landscape in HIVST and linkage to care. It identifies key contributors, high-impact journals, and collaborative networks. The thematic map reveals nuanced research domains, including alcohol dependence, men’s health, outcomes, and user acceptance. The findings offer insights for researchers, policymakers, and practitioners, guiding future directions in the evolving intersection of HIVST and digital health interventions.

Abstract Background A variety of strategies have been used to reach men with HIV self-testing services, including social network-based HIV self-test kits distribution. However, few studies have assessed men’s comfort to distribute to or receive HIV self-test kits from close male friends within the same social network. In this study, we assessed men’s comfort to distribute to and/or receive HIV self-test kits from close male friends and associated factors among men who socialize in networks locally referred to as “camps” in Tanzania. Methods Data are from the baseline survey of a cluster-randomized controlled trial conducted in June 2019 with 18 social networks or “camps” in Dar es Salaam, Tanzania. Participants were 18-year-old or older male camp members who were HIV-negative at the time of enrolment. We used the Generalized Estimating Equations (GEE) to assess factors associated with being comfortable to distribute to and/or receive HIV self-test kits from close male members within one’s social network. Results Of 505 participants, 67.9% (n = 342) reported being comfortable to distribute to while 68.2% (n = 344) were comfortable to receive HIV self-test kits from their close male friends. Ever having heard about HIV self-testing (Adjusted Prevalence Ratio (Adj. PR): 1.6; 95% Confidence Interval [CI]: 1.3, 1.9), willingness to self-test for HIV in front of a sexual partner (Adj. PR: 3.0; 95%CI: 1.5, 6.1) and exposure to peer-led HIV self-testing education and promotion (Adj. PR: 1.4; 95%CI: 1.2, 1.7) were significantly associated with being comfortable to distribute HIV self-test kits to close male members within one’s social network. Similar results were observed for being comfortable to receive HIV self-test kits from a close male friend within one’s social network. Conclusions Overall, these findings suggest that distribution of HIV self-test kits through close male friends could improve the proportion of men reached with HIV self-testing services and improve HIV testing rates in this population where uptake remains low. However, additional promotional strategies such as peer-led HIV self-testing education are needed to raise awareness and increase the proportion of men who are comfortable to receive and/or distribute HIV self-testing kits.

Men in sub-Saharan Africa continue to experience health disparities that are exacerbated by low employment. This study qualitatively assessed men’s perceptions of the economic and health-care-seeking effects of participation in an integrated microfinance and peer health leadership intervention on violence and HIV risk reduction in Tanzania. Three focus group discussions with 27 men, aged 20 to 44 years, examined the perceived effects on income generation, employability, mental health, and uptake of HIV and related health services. All discussions were recorded, transcribed, and analyzed using deductive and inductive coding methods. Men reported that the benefits of the intervention included increased employability and income-earning activities due to greater access to entrepreneurial training, low-interest microfinancing, and male-oriented group supports to start or strengthen their businesses. Increased wages through business or other forms of employment were also attributed to men’s lower anxiety and distress as financial providers for their families. However, men indicated that apart from the uptake of free HIV testing services, there was limited change in overall health-care-seeking behavior given the high clinic fees and lost time to earn income when attending routine health visits. Men recommended that future microfinance and health promotion interventions provide larger loan amounts, less frequent repayment intervals, and access to health and social insurance. Microfinance and peer health leadership interventions may help to address economic and health disparities in poor, urban men. Efforts are needed to assist lower income men in accessing financial tools as well as fee-based preventive and health-care services.

Corneal transparency and avascularity are essential for vision. The avascular cornea transitions into the vascularized conjunctiva at the limbus. Here, we explore a limbal stromal cell sub-population that expresses ABCB5 and has mesenchymal stem cell characteristics. Human primary corneal stromal cells were enriched for ABCB5 by using FACS sorting. ABCB5+ cells expressed the MSC markers CD90, CD73, and CD105. ABCB5+ but not ABCB5- cells from the same donor displayed evidence of pluripotency with a significantly higher colony-forming efficiency and the ability of trilineage differentiation (osteogenic, adipogenic, and chondrogenic). The ABCB5+ cell secretome demonstrated lower levels of the pro-inflammatory protein MIF (macrophage migration inhibitory factor) as well as of the pro-(lymph)angiogenic growth factors VEGFA and VEGFC, which correlated with reduced proliferation of Jurkat cells co-cultured with ABCB5+ cells and decreased proliferation of blood and lymphatic endothelial cells cultured in ABCB5+ cell-conditioned media. These data support the hypothesis that ABCB5+ limbal stromal cells are a putative MSC population with potential anti-inflammatory and anti-(lymph)angiogenic effects. The therapeutic modulation of ABCB5+ limbal stromal cells may prevent cornea neovascularization and inflammation and, if transplanted to other sites in the body, provide similar protective properties to other tissues.

Background: The ability of mesenchymal stromal cells (MSCs) to facilitate regenerative responses in inflamed and injured tissues, coupled with preclinical data suggesting potential to restore defective collagen VII at the dermo-epidermal junction, has raised the hope that MSCs may provide an effective disease-modifying therapy for patients suffering from recessive dystrophic epidermolysis bullosa (RDEB)., Methods: We present a descriptive analysis of the clinical research on systemic MSC administration to RDEB patients available in PubMed, including six early-phase studies and one case report, involving 59 patients who received 1-3 intravenous infusions of MSCs from various sources., Results: Based on 133 MSC infusions, a total of 44 mostly mild adverse events were reported as definitely, possibly or likely related to the study treatment, only two of which led to treatment discontinuation. Improvements were seen in skin manifestations, disease activity, pain, pruritus and quality of life, with considerable heterogeneity in reported outcome variables and measurement tools between studies, and large inter-patient variability within studies., Conclusions: Although the current evidence base is limited, reflecting the typical challenges of clinical research in rare diseases, the reported results suggest potential treatment benefits for patients and provide a rationale for continuing to pursue this therapeutic approach.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severely debilitating disorder caused by pathogenic variants in COL7A1 and is characterized by extreme skin fragility, chronic inflammation, and fibrosis. A majority of patients with RDEB develop squamous cell carcinoma, a highly aggressive skin cancer with limited treatment options currently available. In this study, we utilized an approach leveraging whole-genome sequencing and RNA sequencing across 3 different tissues in a single patient with RDEB to gain insight into possible mechanisms of RDEB-associated squamous cell carcinoma progression and to identify potential therapeutic options. As a result, we identified PLK-1 as a possible candidate for targeted therapy and discovered microsatellite instability and accelerated aging as factors potentially contributing to the aggressive nature and early onset of RDEB squamous cell carcinoma. By integrating multitissue genomic and transcriptomic analyses in a single patient, we demonstrate the promise of bridging the gap between genomic research and clinical applications for developing tailored therapies for patients with rare genetic disorders such as RDEB., (Published by Elsevier Inc.)

Background: Given the high level of product complexity and limited regulatory guidance, designing and implementing appropriate potency assays is often the most challenging part of establishing a quality control testing matrix for a cell-based medicinal product. Among the most elusive tasks are the selection of suitable read-out parameters, the development of assay designs that most closely model the pathophysiological conditions, and the validation of the methods. Here we describe these challenges and how they were addressed in developing an assay that measures the anti-inflammatory potency of mesenchymal stromal cells (MSCs) in an M1 macrophage-dominated inflammatory environment., Methods: An in vitro inflammation model was established by coculturing skin-derived ABCB5 + MSCs with THP-1 monocyte-derived M1-polarized macrophages. Readout was the amount of interleukin 1 receptor antagonist (IL-1RA) secreted by the MSCs in the coculture, measured by an enzyme-linked immunosorbent assay., Results: IL-1RA was quantified with guideline-concordant selectivity, accuracy and precision over a relevant concentration range. Consistent induction of the macrophage markers CD36 and CD80 indicated successful macrophage differentiation and M1 polarization of THP-1 cells, which was functionally confirmed by release of proinflammatory tumor necrosis factor α. Testing a wide range of MSC/macrophage ratios revealed the optimal ratio for near-maximal stimulation of MSCs to secrete IL-1RA, providing absolute maximum levels per individual MSC that can be used for future comparison with clinical efficacy. Batch release testing of 71 consecutively manufactured MSC batches showed a low overall failure rate and a high comparability between donors., Conclusions: We describe the systematic development and validation of a therapeutically relevant, straightforward, robust and reproducible potency assay to measure the immunomodulatory capacity of MSCs in M1 macrophage-driven inflammation. The insights into the challenges and how they were addressed may also be helpful to developers of potency assays related to other cellular functions and clinical indications., Competing Interests: Declaration of Competing of interest MHF is inventor or coinventor of U.S. and international patents assigned to Brigham and Women's Hospital and/or Boston Children's Hospital, licensed to RHEACELL GmbH & Co. KG. MHF and KS-K serve as scientific advisors to RHEACELL. MHF holds stock in RHEACELL. SS, LN, EN-R, AN, SH, LV and JE are employees of RHEACELL. CG is CEO, and MAK is COO of RHEACELL., (Copyright © 2024 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

For years, cancer has been one of the diseases that causes the greatest disease burden in the Netherlands. Cancer does not only have a huge impact on patients and their loved ones, but also on society and healthcare. If the number of cancer patients increases further in the coming years, this impact will only aggravate. This development will also impact dental practice. It is therefore important to assess what awaits us in the coming years. Both with regard to supporting and treating (former) oncology patients. Forinstance, detecting secondary effects of cancer treatments such as oral mucositis and medication- and radiation-related jaw necrosis, as well as the early detection of oral cavity carcinomas and sun-related skin damage on the lips and face. Based on this, plans can be made to meet the demand for dental care as well as possible and to reduce the impact of cancer for both the individual patient and for society as a whole.

Objectives: To assess whether there are differences in the effects of time to treatment interval (TTI) on patient survival for head and neck cancer (HNC) sites in order to provide evidence that can support decision-making regarding prioritizing treatment., Materials and Methods: Patients in the Netherlands with a first primary HNC without distant metastasis between 2010 and 2014 were included for analysis (N = 10,486). TTI was defined as the time from pathologic diagnosis to the start of initial treatment. Overall survival (OS), cox regression analyses and cubic spline hazard models were calculated and visualized., Results: Overall, the hazard of dying was higher (HR = 1.003; 95 % CI 1.001-1.005) with each additional day until treatment initiation. The pattern, as visualized in cubic spline graphs, differed by site the hazard increased more steeply with increasing TTI for oral cavity cancer. For oropharyngeal and laryngeal cancer, a slight increase commenced after a longer TTI than for oral cavity cancer, while there was hardly an increase in hazard with increasing TTI for hypopharyngeal cancer., Conclusion: The relationship between longer TTI and decreased survival was confirmed, but slight variations in the pattern of the hazard of dying by TTI by tumour site were observed. These findings could support decisions on prioritizing treatment. However, other aspects such as extent of treatment and quality of life should be investigated further so this can also be included., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Acute kidney injury (AKI) is characterized by a rapid reduction in renal function and glomerular filtration rate (GFR). The broadly used anti-cancer chemotherapeutic agent cisplatin often induces AKI as an adverse drug side effect. Therapies targeted at the reversal of AKI and its potential progression to chronic kidney disease or end-stage renal disease are currently insufficiently effective. Mesenchymal stromal cells (MSCs) possess diverse immunomodulatory properties that confer upon them significant therapeutic potential for the treatment of diverse inflammatory disorders. Human dermal MSCs expressing ATP-Binding Cassette member B5 (ABCB5) have shown therapeutic efficacy in clinical trials in chronic skin wounds or recessive dystrophic epidermolysis bullosa. In preclinical studies, ABCB5+ MSCs have also shown to reverse metabolic reprogramming in polycystic kidney cells, suggesting a capacity for this cell subset to improve also organ function in kidney diseases. Here, we aimed to explore the therapeutic capacity of ABCB5+ MSCs to improve renal function in a preclinical rat model of cisplatin-induced AKI. First, the anti-apoptotic and immunomodulatory capacity was compared against research-grade adipose stromal cells (ASCs). Then, cross-species immunomodulatory capacity was checked, testing first inhibition of mitogen-driven peripheral blood mononuclear cells and then modulation of macrophage function. Finally, therapeutic efficacy was evaluated in a cisplatin AKI model. First, ABCB5+ MSCs suppressed cisplatin-induced apoptosis of human conditionally-immortalized proximal tubular epithelial cells in vitro , most likely by reducing oxidative stress. Second, ABCB5+ MSCs inhibited the proliferation of either human or rat peripheral blood mononuclear cells, in the human system via the Indoleamine/kynurenine axis and in the murine context via nitric oxide/nitrite. Third, ABCB5+ MSCs decreased TNF-α secretion after lipopolysaccharide stimulation and modulated phagocytosis and in both human and rat macrophages, involving prostaglandin E2 and TGF-β1, respectively. Fourth, clinical-grade ABCB5+ MSCs grafted intravenously and intraperitoneally to a cisplatin-induced AKI murine model exerted modulatory effects on mRNA expression patterns toward an anti-inflammatory and pro-regenerative state despite an apparent lack of amelioration of renal damage at physiologic, metabolic, and histologic levels. Our results demonstrate anti-inflammatory and pro-regenerative effects of clinical grade ABCB5+ MSCs in vitro and in vivo and suggest potential therapeutic utility of this cell population for treatment or prevention of cisplatin chemotherapy-induced tissue toxicity., Competing Interests: MK is CSO of RHEACELL. CD is project manager of RHEACELL GmbH & Co. KG, Heidelberg, Germany. CG is Managing Partner and holds equity in RHEACELL GmbH & Co. KG. MF is inventor or co-inventor of US and international patents assigned to Brigham and Women’s Hospital and/or Boston Children’s Hospital and licensed to RHEACELL GmbH & Co. KG Heidelberg, Germany. He also serves as a scientific advisor to and holds equity in RHEACELL GmbH & Co. KG. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Rendra, Crigna, Daniele, Sticht, Cueppers, Kluth, Ganss, Frank, Gretz and Bieback.)

Hybrid breeding for increased vigour has been used for over a century to boost agricultural outputs without requiring higher inputs. While this approach has led to some of the most substantial gains in crop productivity, breeding barriers have fundamentally limited soybean (Glycine max) from reaping the benefits of hybrid vigour. Soybean flowers self-pollinate prior to opening and thus are not readily amenable to outcrossing. In this study, we demonstrate that the barnase/barstar male sterility/rescue system can be used in soybean to produce hybrid seeds. By expressing the cytotoxic ribonuclease, barnase, under a tapetum-specific promoter in soybean anthers, we are able to completely block pollen maturation, creating male sterile plants. We show that fertility can be rescued in the F1 generation of these barnase-expressing lines when they are crossed with pollen from plants that express the barnase inhibitor, barstar. Importantly, we found that the successful rescue of male fertility is dependent on the relative dosage of barnase and barstar. When barnase and barstar were expressed under the same tapetum-specific promoter, the F1 offspring remained male sterile. When we expressed barstar under a relatively stronger promoter than barnase, we were able to achieve a successful rescue of male fertility in the F1 generation. This work demonstrates the successful implementation of a biotechnology approach to produce fertile hybrid offspring in soybean., (© 2023 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.)

BCAM-positive basal limbal epithelial cells are an early transit-amplifying cell population (TAC) capable of holoclone formation and corneal epithelial differentiation. Here, we present a protocol for isolating BCAM-positive cells from human donor corneas by flow cytometry and cell sorting. We describe steps for cell dissection and dissociation, antibody staining, and flow cytometry. We then detail procedures for culturing the purified BCAM-positive and BCAM-negative cells for holoclone and cell sheet formation assays to study the factors that regulate corneal regeneration. For complete details on the use and execution of this protocol, please refer to Sasamoto et al. 1 ., Competing Interests: Declaration of interests M.H.F. and N.Y.F. are inventors or co-inventors of US and international patents assigned to Brigham and Women’s Hospital, Boston Children’s Hospital, the Massachusetts Eye and Ear Infirmary, and/or the VA Boston Healthcare System, Boston, MA, licensed to Rheacell GmbH & Co. KG (Heidelberg, Germany). M.H.F. serves as a scientific advisor and holds equity in Rheacell GmbH & Co. KG., (Copyright © 2023. Published by Elsevier Inc.)

Interspecies grafting is an economically relevant technique that allows beneficial shoot and root combinations from separate species to be combined. One hypothesis for the basis of graft compatibility revolves around taxonomic relatedness. To test how phylogenetic distance affects interspecific graft compatibility within the economically important Solanaceae subfamily, Solanoideae, we characterized the anatomical and biophysical integrity of graft junctions between four species: tomato (Solanum lycopersicum), eggplant (Solanum melongena), pepper (Capsicum annuum), and groundcherry (Physalis pubescens). We analyzed the survival, growth, integrity, and cellular composition of the graft junctions. Utilizing various techniques, we were able to quantitatively assess compatibility among the interspecific grafts. Even though most of our graft combinations could survive, we show that only intrageneric combinations between tomato and eggplant are compatible. Unlike incompatible grafts, the formation of substantial vascular reconnections between tomato and eggplant in the intrageneric heterografts likely contributed to biophysically stable grafts. Furthermore, we identified 10 graft combinations that show delayed incompatibility, providing a useful system to pursue deeper work into graft compatibility. This work provides new evidence that graft compatibility may be limited to intrageneric combinations within the Solanoideae subfamily. Further research amongst additional Solanaceous species can be used to test the extent to which our hypothesis applies to this family., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Quantitative polymerase chain reaction (qPCR) has emerged as an important bioanalytical method for assessing the pharmacokinetics of human-cell-based medicinal products after xenotransplantation into immunodeficient mice. A particular challenge in bioanalytical qPCR studies is that the different tissues of the host organism can affect amplification efficiency and amplicon detection to varying degrees, and ignoring these matrix effects can easily cause a significant underestimation of the true number of target cells in a sample. Here, we describe the development and drug regulatory-compliant validation of a TaqMan ® qPCR assay for the quantification of mesenchymal stromal cells in the range of 125 to 20,000 cells/200 µL lysate via the amplification of a human-specific, highly repetitive α-satellite DNA sequence of the chromosome 17 centromere region HSSATA17. An assessment of matrix effects in 14 different mouse tissues and blood revealed a wide range of spike recovery rates across the different tissue types, from 11 to 174%. Based on these observations, we propose performing systematic spike-and-recovery experiments during assay validation and correcting for the effects of the different tissue matrices on cell quantification in subsequent bioanalytical studies by multiplying the back-calculated cell number by tissue-specific factors derived from the inverse of the validated percent recovery rate.

Background and Aims: Recessive dystrophic epidermolysis bullosa (RDEB) is a hereditary, rare, devastating and life-threatening skin fragility disorder with a high unmet medical need. In a recent international, single-arm clinical trial, treatment of 16 patients (aged 6-36 years) with three intravenous infusions of 2 × 10 6  immunomodulatory ABCB5 + dermal mesenchymal stromal cells (MSCs)/kg on days 0, 17 and 35 reduced disease activity, itch and pain. A post-hoc analysis was undertaken to assess the potential effects of treatment with ABCB5 + MSCs on the overall skin wound healing in patients suffering from RDEB., Methods: Documentary photographs of the affected body regions taken on days 0, 17, 35 and at 12 weeks were evaluated regarding proportion, temporal course and durability of wound closure as well as development of new wounds., Results: Of 168 baseline wounds in 14 patients, 109 (64.9%) wounds had closed at week 12, of which 63.3% (69 wounds) had closed already by day 35 or day 17. Conversely, 74.2% of the baseline wounds that had closed by day 17 or day 35 remained closed until week 12. First-closure ratio within 12 weeks was 75.6%. The median rate of newly developing wounds decreased significantly (P = 0.001) by 79.3%., Conclusions: Comparison of the findings with published data from placebo arms and vehicle-treated wounds in controlled clinical trials suggests potential capability of ABCB5 + MSCs to facilitate wound closure, prolongate wound recurrence and decelerate formation of new wounds in RDEB. Beyond suggesting therapeutic efficacy for ABCB5 + MSCs, the analysis might stimulate researchers who develop therapies for RDEB and other skin fragility disorders to not only assess closure of preselected target wounds but pay attention to the patients' dynamic and diverse overall wound presentation as well as to the durability of achieved wound closure and the development of new wounds., Trial Registration: Clinicaltrials.gov NCT03529877; EudraCT 2018-001009-98., Competing Interests: Declaration of Competing Interest NYF and MHF are inventors or co-inventors of U.S. and international patents assigned to Brigham and Women's Hospital, Boston Children's Hospital, and/or the VA Boston Healthcare System, Boston, Massachusetts, USA, licensed to TICEBA GmbH, Heidelberg, Germany, and RHEACELL GmbH & Co. KG, Heidelberg, Germany. MHF serves as scientific advisor and holds stock in TICEBA GmbH and RHEACELL GmbH & Co. KG. DK and JT serve as scientific advisors to RHEACELL. KD, CD and SF are employees of RHEACELL. ENR is employee of TICEBA. CG is CEO, and MAK is CSO of TICEBA and RHEACELL. JAM declares that he has no conflicts of interest., (Copyright © 2023 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

The limbus, the vascularized junction between the cornea and conjunctiva, is thought to function as a barrier against corneal neovascularization. However, the exact mechanisms regulating this remain unknown. In this study, the limbal epithelial stem cell (LESC) marker ABCB5 was used to investigate the role of LESCs in corneal neovascularization. In an ABCB5KO model, a mild but significant increase of limbal lymphatic and blood vascular network complexity was observed in developing mice (4 weeks) but not in adult mice. Conversely, when using a cornea suture model, the WT animals exhibited a mild but significant increase in the number of lymphatic vessel sprouts compared to the ABCB5KO, suggesting a contextual anti-lymphangiogenic effect of ABCB5 on the limbal vasculature during development, but a pro-lymphangiogenic effect under inflammatory challenge in adulthood. In addition, conditioned media from ABCB5-positive cultured human limbal epithelial cells (ABCB5+) stimulated human blood and lymphatic endothelial cell proliferation and migration. Finally, a proteomic analysis demonstrated ABCB5+ cells have a pro(lymph)angiogenic as well as an anti-inflammatory profile. These data suggest a novel dual, context-dependent role of ABCB5+ LESCs, inhibiting developmental but promoting inflammatory (lymph)angiogenesis in adulthood and exerting anti-inflammatory effects. These findings are of high clinical relevance in relation to LESC therapy against blindness.

Organismal communication entails encoding a message that is sent over space or time to a recipient cell, where that message is decoded to activate a downstream response. Defining what qualifies as a functional signal is essential for understanding intercellular communication. In this review, we delve into what is known and unknown in the field of long-distance messenger RNA (mRNA) movement and draw inspiration from the field of information theory to provide a perspective on what defines a functional signaling molecule. Although numerous studies support the long-distance movement of hundreds to thousands of mRNAs through the plant vascular system, only a small handful of these transcripts have been associated with signaling functions. Deciphering whether mobile mRNAs generally serve a role in plant communication has been challenging, due to our current lack of understanding regarding the factors that influence mRNA mobility. Further insight into unsolved questions regarding the nature of mobile mRNAs could provide an understanding of the signaling potential of these macromolecules., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Recessive dystrophic epidermolysis (RDEB) is a rare, inherited, and currently incurable skin blistering disorder characterized by cyclically recurring wounds coexisting with chronic non-healing wounds. In a recent clinical trial, three intravenous infusions of skin-derived ABCB5 + mesenchymal stromal cells (MSCs) to 14 patients with RDEB improved the healing of wounds that were present at baseline. Since in RDEB even minor mechanical forces perpetually provoke the development of new or recurrent wounds, a post-hoc analysis of patient photographs was performed to specifically assess the effects of ABCB5 + MSCs on new or recurrent wounds by evaluating 174 wounds that occurred after baseline. During 12 weeks of systemic treatment with ABCB5 + MSCs, the number of newly occurring wounds declined. When compared to the previously reported healing responses of the wounds present at baseline, the newly occurring wounds healed faster, and a greater portion of healed wounds remained stably closed. These data suggest a previously undescribed skin-stabilizing effect of treatment with ABCB5 + MSCs and support repeated dosing of ABCB5 + MSCs in RDEB to continuously slow the wound development and accelerate the healing of new or recurrent wounds before they become infected or progress to a chronic, difficult-to-heal stage.

Euphorbia peplus (petty spurge) is a small, fast-growing plant that is native to Eurasia and has become a naturalized weed in North America and Australia. Euphorbia peplus is not only medicinally valuable, serving as a source for the skin cancer drug ingenol mebutate, but also has great potential as a model for latex production owing to its small size, ease of manipulation in the laboratory, and rapid reproductive cycle. To help establish E. peplus as a new model, we generated a 267.2-Mb Hi-C-anchored PacBio HiFi nuclear genome assembly with a BUSCO score of 98.5%, a genome annotation based on RNA-seq data from six organs, and publicly accessible tools including a genome browser and an interactive organ-specific expression atlas. Chromosome number is highly variable across Euphorbia species. Using a comparative analysis of our newly sequenced E. peplus genome with other Euphorbiaceae genomes, we show that variation in Euphorbia chromosome number between E. peplus and Euphorbia lathyris is likely due to fragmentation and rearrangement rather than chromosomal duplication followed by diploidization of the duplicated sequence. Moreover, we found that the E. peplus genome is relatively compact compared with related members of the genus in part due to restricted expansion of the Ty3 transposon family. Finally, we identify a large gene cluster that contains many previously identified enzymes in the putative ingenol mebutate biosynthesis pathway, along with additional gene candidates for this biosynthetic pathway. The genomic resources we have created for E. peplus will help advance research on latex production and ingenol mebutate biosynthesis in the commercially important Euphorbiaceae family., (© The Author(s) 2023. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Background: Hypoxia in ischemic disease impairs Ca 2+ homeostasis and may promote angiogenesis. The therapeutic efficacy of mesenchymal stromal cells (MSCs) in peripheral arterial occlusive disease is well established, yet its influence on cellular Ca 2+ homeostasis remains to be elucidated. We addressed the influence of ATP-binding cassette subfamily B member 5 positive mesenchymal stromal cells (ABCB5 + MSCs) on Ca 2+ homeostasis in hypoxic human umbilical vein endothelial cells (HUVECs) in vitro and in vivo., Methods: Hypoxia was induced in HUVECs by Cobalt (II) chloride (CoCl 2 ) or Deferoxamine (DFO). Dynamic changes in the cytosolic- and endoplasmic reticulum (ER) Ca 2+ and changes in reactive oxygen species were assessed by appropriate fluorescence-based sensors. Metabolic activity, cell migration, and tube formation were assessed by standard assays. Acute-on-chronic ischemia in Apolipoprotein E knock-out (ApoE -/- ) mice was performed by double ligation of the right femoral artery (DFLA). ABCB5 + MSC cells were injected into the ischemic limb. Functional recovery after DFLA and histology of gastrocnemius and aorta were assessed., Results: Hypoxia-induced impairment of cytosolic and ER Ca 2+ were restored by ABCB5 + MSCs or their conditioned medium. Similar was found for changes in intracellular ROS production, metabolic activity, migratory ability and tube formation. The restoration was paralleled by an increased expression of the Ca 2+ transporter Sarco-/endoplasmic reticulum ATPase 2a (SERCA2a) and the phosphorylation of Phospholamban (PLN). In acute-on-chronic ischemia, ABCB5 + MSCs treated mice showed a higher microvascular density, increased SERCA2a expression and PLN phosphorylation relative to untreated controls., Conclusions: ABCB5 + MSCs therapy can restore cellular Ca 2+ homeostasis, which may beneficially affect the angiogenic function of endothelial cells under hypoxia in vitro and in vivo., (© 2023. The Author(s).)

Epigenetic DNA modification by 5-hydroxymethylcytosine (5hmC), generated by the Ten-eleven translocation (TET) dioxygenases, regulates diverse biological functions in many organ tissues, including the mammalian eye. For example, 5hmC has been shown to be involved in epigenetic regulation of retinal gene expression. However, a functional role of 5hmC in corneal differentiation has not been investigated to date. Here, we examined 5hmC and TET function in the human cornea. We found 5hmC highly expressed in MUC16-positive terminally differentiated cells that also co-expressed the 5hmC-generating enzyme TET2. TET2 knockdown (KD) in cultured corneal epithelial cells led to significant reductions of 5hmC peak distributions and resulted in transcriptional repression of molecular pathways involved in corneal differentiation, as evidenced by downregulation of MUC4, MUC16, and Keratin 12. Additionally, integrated TET2 KD RNA-seq and genome-wide Reduced Representation Hydroxymethylation Profiling revealed novel epigenetically regulated genes expressed by terminally differentiated cells, including KRT78 , MYEOV , and MAL . In aggregate, our findings reveal a novel function of TET2 in the epigenetic regulation of corneal epithelial gene expression and identify novel TET2-controlled genes expressed in differentiated corneal epithelial cells. These results point to potential roles for TET2 induction strategies to enhance treatment of corneal diseases associated with abnormal epithelial maturation.

The ATP-binding cassette superfamily member ABCB5 identifies a subset of skin-resident mesenchymal stem cells (MSCs) that exhibit potent immunomodulatory and wound healing-promoting capacities along with superior homing ability. The ABCB5 + MSCs can be easily accessed from discarded skin samples, expanded, and delivered as a highly homogenous medicinal product with standardized potency. A range of preclinical studies has suggested therapeutic efficacy of ABCB5 + MSCs in a variety of currently uncurable skin and non-skin inflammatory diseases, which has been substantiated thus far by distinct clinical trials in chronic skin wounds or recessive dystrophic epidermolysis bullosa. Therefore, skin-derived ABCB5 + MSCs have the potential to provide a breakthrough at the forefront of MSC-based therapies striving to fulfill current unmet medical needs. The most recent milestones in this regard are the approval of a phase III pivotal trial of ABCB5 + MSCs for treatment of recessive dystrophic and junctional epidermolysis bullosa by the US Food and Drug Administration, and national market access of ABCB5 + MSCs (AMESANAR ® ) for therapy-refractory chronic venous ulcers under the national hospital exemption pathway in Germany.

Pterygium pathogenesis is often attributed to a population of altered limbal stem cells, which initiate corneal invasion and drive the hyperproliferation and fibrosis associated with the disease. These cells are thought to undergo epithelial to mesenchymal transition (EMT) and to contribute to subepithelial stromal fibrosis. In this study, the presence of the novel limbal stem cell marker ABCB5 in clusters of basal epithelial pterygium cells co-expressing with P63α and P40 is reported. ABCB5-positive pterygium cells also express EMT-associated fibrosis markers including vimentin and α-SMA while their β-catenin expression is reduced. By using a novel in vitro model of two-dose UV-induced EMT activation on limbal epithelial cells, we could observe the dysregulation of EMT-related proteins including an increase of vimentin and α-SMA as well as downregulation of β-catenin in epithelial cells correlating to downregulation of ABCB5. The sequential irradiation of limbal fibroblasts also induced an increase in vimentin and α-SMA. Taken together, these data demonstrate for the first time the expression of ABCB5 in pterygium stem cell activity and EMT-related events while the involvement of limbal stem cells in pterygium pathogenesis is exhibited via sequential irradiation of limbal epithelial cells. The later in vitro approach can be used to further study the involvement of limbal epithelium UV-induced EMT in pterygium pathogenesis and help identify novel treatments against pterygium growth and recurrence., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Christoph Ganss reports financial support was provided by Ticeba GmbH. Markus H Frank reports financial support was provided by Ticeba GmbH. Maria Notara reports equipment, drugs, or supplies was provided by Ticeba GmbH. Christoph Masslo reports financial support was provided by Ticeba GmbH. Andreas Kluth reports financial support was provided by Ticeba GmbH. Christoph Ganss reports a relationship with Ticeba GmbH that includes: board membership. Andreas Kluth reports a relationship with Ticeba GmbH that includes: employment. Christoph Masslo reports a relationship with Ticeba GmbH that includes: employment. Markus Frank reports a relationship with Ticeba GmbH that includes: consulting or advisory. Maria Notara reports a relationship with Ticeba GmbH that includes: non-financial support. Markus Frank has patent issued to Ticeba Gmbh. Natasha Frank has patent pending to Ticeba Gmbh. Potential Conflict of interest Disclosure: Christoph Ganss: CEO and shareholder of TICEBA GmbH; CEO of RHEACELL GmbH & Co. KG Andreas Kluth: CSO of TICEBA GmbH; CSO of RHEACELL GmbH & Co. KG Christoph Maβlo: Project coordinator of RHEACELL GmbH & Co. KG Potential Conflict of Interest Disclosure: N.Y.F. and M.H.F. are inventors or co-inventor sof US and international patents assigned to Brigham and Women’s Hospital and/or Boston Children’s Hospital, Boston, MA, and licensed to TICEBA GmbH (Heidelberg, Germany) and RHEACELL GmbH & Co. KG (Heidelberg, Germany). M.H.F. serves as a scientific advisor to TICEBA GmbH and RHEACELL GmbH & Co. KG., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: While rapid healing of diabetic foot ulcers (DFUs) is highly desirable to avoid infections, amputations and life-threatening complications, DFUs often respond poorly to standard treatment. GMP-manufactured skin-derived ABCB5 + mesenchymal stem cells (MSCs) might provide a new adjunctive DFU treatment, based on their remarkable skin wound homing and engraftment potential, their ability to adaptively respond to inflammatory signals, and their wound healing-promoting efficacy in mouse wound models and human chronic venous ulcers., Methods: The angiogenic potential of ABCB5 + MSCs was characterized with respect to angiogenic factor expression at the mRNA and protein level, in vitro endothelial trans-differentiation and tube formation potential, and perfusion-restoring capacity in a mouse hindlimb ischemia model. Finally, the efficacy and safety of ABCB5 + MSCs for topical adjunctive treatment of chronic, standard therapy-refractory, neuropathic plantar DFUs were assessed in an open-label single-arm clinical trial., Results: Hypoxic incubation of ABCB5 + MSCs led to posttranslational stabilization of the hypoxia-inducible transcription factor 1α (HIF-1α) and upregulation of HIF-1α mRNA levels. HIF-1α pathway activation was accompanied by upregulation of vascular endothelial growth factor (VEGF) transcription and increase in VEGF protein secretion. Upon culture in growth factor-supplemented medium, ABCB5 + MSCs expressed the endothelial-lineage marker CD31, and after seeding on gel matrix, ABCB5 + MSCs demonstrated formation of capillary-like structures comparable with human umbilical vein endothelial cells. Intramuscularly injected ABCB5 + MSCs to mice with surgically induced hindlimb ischemia accelerated perfusion recovery as measured by laser Doppler blood perfusion imaging and enhanced capillary proliferation and vascularization in the ischemic muscles. Adjunctive topical application of ABCB5 + MSCs onto therapy-refractory DFUs elicited median wound surface area reductions from baseline of 59% (full analysis set, n = 23), 64% (per-protocol set, n = 20) and 67% (subgroup of responders, n = 17) at week 12, while no treatment-related adverse events were observed., Conclusions: The present observations identify GMP-manufactured ABCB5 + dermal MSCs as a potential, safe candidate for adjunctive therapy of otherwise incurable DFUs and justify the conduct of a larger, randomized controlled trial to validate the clinical efficacy., Trial Registration: ClinicalTrials.gov, NCT03267784, Registered 30 August 2017, https://clinicaltrials.gov/ct2/show/NCT03267784., (© 2022. The Author(s).)

The corneal epithelium is renowned for high regenerative potential, which is dependent on the coordinated function of its diverse progenitor subpopulations. However, the molecular pathways governing corneal epithelial progenitor differentiation are incompletely understood. Here, we identify a highly proliferative limbal epithelial progenitor subpopulation characterized by expression of basal cell adhesion molecule (BCAM) that is capable of holocone formation and corneal epithelial sheet generation. BCAM-positive cells can be found among ABCB5-positive limbal stem cells (LSCs) as well as among ABCB5-negative limbal epithelial cell populations. Mechanistically, we show that BCAM is functionally required for cellular migration and differentiation and that its expression is regulated by the transcription factor p63. In aggregate, our study identifies limbal BCAM expression as a marker of highly proliferative corneal epithelial progenitor cells and defines the role of BCAM as a critical molecular mediator of corneal epithelial differentiation., Competing Interests: Declaration of interests M.H.F., B.R.K., and N.Y.F. are inventors or co-inventors of US and international patents assigned to Brigham and Women’s Hospital, Boston Children’s Hospital, the Massachusetts Eye and Ear Infirmary, and/or the VA Boston Healthcare System, Boston, MA, licensed to Ticeba GmbH (Heidelberg, Germany) and Rheacell GmbH & Co. KG (Heidelberg, Germany). M.H.F. serves as a scientific advisor to Ticeba GmbH and Rheacell GmbH & Co. KG., (Published by Elsevier Inc.)

The Solanaceae or "nightshade" family is an economically important group with remarkable diversity. To gain a better understanding of how the unique biology of the Solanaceae relates to the family's small RNA (sRNA) genomic landscape, we downloaded over 255 publicly available sRNA data sets that comprise over 2.6 billion reads of sequence data. We applied a suite of computational tools to predict and annotate two major sRNA classes: (1) microRNAs (miRNAs), typically 20- to 22-nucleotide (nt) RNAs generated from a hairpin precursor and functioning in gene silencing and (2) short interfering RNAs (siRNAs), including 24-nt heterochromatic siRNAs typically functioning to repress repetitive regions of the genome via RNA-directed DNA methylation, as well as secondary phased siRNAs and trans-acting siRNAs generated via miRNA-directed cleavage of a polymerase II-derived RNA precursor. Our analyses described thousands of sRNA loci, including poorly understood clusters of 22-nt siRNAs that accumulate during viral infection. The birth, death, expansion, and contraction of these sRNA loci are dynamic evolutionary processes that characterize the Solanaceae family. These analyses indicate that individuals within the same genus share similar sRNA landscapes, whereas comparisons between distinct genera within the Solanaceae reveal relatively few commonalities., (© The Author(s) 2022. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Severe angiopathy is a major driver for diabetes-associated secondary complications. Knowledge on the underlying mechanisms essential for advanced therapies to attenuate these pathologies is limited. Injection of ABCB5 + stromal precursors at the edge of nonhealing diabetic wounds in a murine db/db model, closely mirroring human type 2 diabetes, profoundly accelerates wound closure. Strikingly, enhanced angiogenesis was substantially enforced by the release of the ribonuclease angiogenin from ABCB5 + stromal precursors. This compensates for the profoundly reduced angiogenin expression in nontreated murine chronic diabetic wounds. Silencing of angiogenin in ABCB5 + stromal precursors before injection significantly reduced angiogenesis and delayed wound closure in diabetic db/db mice, implying an unprecedented key role for angiogenin in tissue regeneration in diabetes. These data hold significant promise for further refining stromal precursors-based therapies of nonhealing diabetic foot ulcers and other pathologies with impaired angiogenesis., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). While the ocular surface is considered one of the major SARS-CoV2 transmission routes, the specific cellular tropism of SARS-CoV2 is not fully understood. In the current study, we evaluated the expression and regulation of two SARS-CoV2 viral entry proteins, TMPRSS2 and ACE2, in human ocular epithelial cells and stem cells., Methods: TMPRSS2 and ACE2 expression in ABCB5-positive limbal stem cells (LSCs) were assessed by RNAseq, flow cytometry and immunohistochemistry. PAX6, TMPRSS2, and ACE2 mRNA expression values were obtained from the GSE135455 and DRA002960 RNA-seq datasets. siRNA-mediated PAX6 knockdown (KD) was performed in limbal and conjunctival epithelial cells. TMPRSS2 and ACE2 expression in the PAX6 KD cells was analyzed by qRT-PCR and Western blot., Results: We found that ABCB5-positive LSCs express high levels of TMPRSS2 and ACE2 compared to ABCB5-negative limbal epithelial cells. Mechanistically, gene knockout and overexpression models revealed that the eye transcription factor PAX6 negatively regulates TMPRSS2 expression. Therefore, low levels of PAX6 in ABCB5-positive LSCs promote TMPRSS2 expression, and high levels of TMPRSS2 and ACE2 expression by LSCs indicate enhanced susceptibility to SARS-CoV2 infection in this stem cell population., Conclusions: Our study points to a need for COVID-19 testing of LSCs derived from donor corneas before transplantation to patients with limbal stem cell deficiency. Furthermore, our findings suggest that expandable human ABCB5+ LSC cultures might represent a relevant novel model system for studying cellular SARS-CoV2 viral entry mechanisms and evaluating related targeting strategies., (Published by Elsevier Inc.)

A significant number of chronic venous ulcers (CVUs) fail to heal despite of guideline-conform standard of care. Skin-derived ABCB5 + mesenchymal stem cells (MSCs) can dampen the sustained IL-1β-driven inflammation present in chronic wounds. Based on their wound healing-facilitating effects in a mouse CVU model and an autologous first-in-human study, ABCB5 + MSCs have emerged as a potential candidate for cell-based advanced therapy of non-healing CVUs. In the present interventional, multicenter, single-arm, phase I/IIa clinical trial, subjects whose CVU had emerged as standard therapy-resistant received one or two topical applications of 1×10 6 allogeneic ABCB5 + MSCs/cm 2 wound area in addition to standard treatment. Out of 83 treatment-emergent adverse events, only three were judged related to the cell product; they were mild or moderate and recovered without sequelae. Wound size markedly decreased from baseline to week 12, resulting in a median wound size reduction of 76% (full analysis set, N=31), 78% (per-protocol set, N=27) and 87% (subset of responders; n=21). In conclusion, the study treatment was well tolerated and safe. The treatment elicited a profound wound size reduction within 12 weeks, identifying ABCB5 + MSCs as a potential candidate for adjunctive therapy of otherwise incurable CVUs. These results justify the conduct of a larger, randomized, controlled trial to confirm clinical efficacy., Competing Interests: CONFLICT OF INTEREST NYF and MHF are inventors or co-inventors of US and international patents assigned to Brigham and Women’s Hospital and/or Boston Children’s Hospital, Boston, MA, USA, licensed to TICEBA GmbH, Heidelberg, Germany, and RHEACELL GmbH & Co. KG, Heidelberg, Germany. MHF and KSK serve as scientific advisors to TICEBA and RHEACELL and participate in corporate-sponsored research collaborations with RHEACELL. KD, AKD, KK and HS are employees of RHEACELL. ENR, JE, SB and SS are employees of TICEBA. CG is CEO, and MAK is CSO of RHEACELL and TICEBA. The remaining authors state no conflict of interest.

Color patterning contributes to important plant traits that influence ecological interactions, horticultural breeding, and agricultural performance. High-throughput phenotyping of color is valuable for understanding plant biology and selecting for traits related to color during plant breeding. Here we present ColourQuant, an automated high-throughput pipeline that allows users to extract color phenotypes from images. This pipeline includes methods for color phenotyping using mean pixel values, a Gaussian density estimator of CIELAB color, and the analysis of shape-independent color patterning by circular deformation., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Latex-containing cells called laticifers are present in at least 41 flowering plant families and are thought to have convergently evolved at least 12 times. These cells are known to function in defense, but little is known about the molecular genetic mechanisms of their development. The expansion of laticifers into their distinctive tube shape can occur through two distinct mechanisms, cell fusion and intrusive growth. The mechanism and extent of intrusive laticifer growth are still being investigated. Hormonal regulation by jasmonic acid and ethylene is important for both laticifer differentiation and latex biosynthesis. Current evidence suggests that laticifers can be specified independently of latex production, but extensive latex production requires specified laticifers. Laticifers are an emerging system for studying the intersection of cell identity specification and specialized metabolism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

BACKGROUNDRecessive dystrophic epidermolysis bullosa (RDEB) is a rare, devastating, and life-threatening inherited skin fragility disorder that comes about due to a lack of functional type VII collagen, for which no effective therapy exists. ABCB5+ dermal mesenchymal stem cells (ABCB5+ MSCs) possess immunomodulatory, inflammation-dampening, and tissue-healing capacities. In a Col7a1-/- mouse model of RDEB, treatment with ABCB5+ MSCs markedly extended the animals' lifespans.METHODSIn this international, multicentric, single-arm, phase I/IIa clinical trial, 16 patients (aged 4-36 years) enrolled into 4 age cohorts received 3 i.v. infusions of 2 × 106 ABCB5+ MSCs/kg on days 0, 17, and 35. Patients were followed up for 12 weeks regarding efficacy and 12 months regarding safety.RESULTSAt 12 weeks, statistically significant median (IQR) reductions in the Epidermolysis Bullosa Disease Activity and Scarring Index activity (EBDASI activity) score of 13.0% (2.9%-30%; P = 0.049) and the Instrument for Scoring Clinical Outcome of Research for Epidermolysis Bullosa clinician (iscorEB‑c) score of 18.2% (1.9%-39.8%; P = 0.037) were observed. Reductions in itch and pain numerical rating scale scores were greatest on day 35, amounting to 37.5% (0.0%-42.9%; P = 0.033) and 25.0% (-8.4% to 46.4%; P = 0.168), respectively. Three adverse events were considered related to the cell product: 1 mild lymphadenopathy and 2 hypersensitivity reactions. The latter 2 were serious but resolved without sequelae shortly after withdrawal of treatment.CONCLUSIONThis trial demonstrates good tolerability, manageable safety, and potential efficacy of i.v. ABCB5+ MSCs as a readily available disease-modifying therapy for RDEB and provides a rationale for further clinical evaluation.TRIAL REGISTRATIONClinicaltrials.gov NCT03529877; EudraCT 2018-001009-98.FUNDINGThe trial was sponsored by RHEACELL GmbH & Co. KG. Contributions by NYF and MHF to this work were supported by the NIH/National Eye Institute (NEI) grants RO1EY025794 and R24EY028767.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare, incurable blistering skin disease caused by biallelic mutations in type VII collagen (C7). Advancements in treatment of RDEB have come from harnessing the immunomodulatory potential of mesenchymal stem cells (MSCs). Although human bone marrow-derived MSC (BM-MSC) trials in RDEB demonstrate improvement in clinical severity, the mechanisms of MSC migration to and persistence in injured skin and their contributions to wound healing are not completely understood. A unique subset of MSCs expressing ATP-binding cassette subfamily member 5 (ABCB5) resides in the reticular dermis and exhibits similar immunomodulatory characteristics to BM-MSCs. Our work aimed to test the hypothesis that skin-derived ABCB5+ dermal MSCs (DSCs) possess superior skin homing ability compared to BM-MSCs in immunodeficient NOD-scid IL2rgamma null (NSG) mice. Compared to BM-MSCs, peripherally injected ABCB5+ DSCs demonstrated superior homing and engraftment of wounds. Furthermore, ABCB5+ DSCs vs BM-MSCs cocultured with macrophages induced less anti-inflammatory interleukin-1 receptor antagonist (IL-1RA) production. RNA sequencing of ABCB5+ DSCs compared to BM-MSCs showed unique expression of major histocompatibility complex class II and Homeobox (Hox) genes, specifically HOXA3. Critical to inducing migration of endothelial and epithelial cells for wound repair, increased expression of HOXA3 may explain superior skin homing properties of ABCB5+ DSCs. Further discernment of the immunomodulatory mechanisms among MSC populations could have broader regenerative medicine implications beyond RDEB treatment., (© 2021 AlphaMed Press.)

Human induced pluripotent stem cells (hiPSCs) can generate a multiplicity of organoids, yet no compelling evidence currently exists as to whether or not these contain tissue-specific, holoclone-forming stem cells. Here, we show that a subpopulation of cells in a hiPSC-derived corneal epithelial cell sheet is positive for ABCB5 (ATP-binding cassette, sub-family B, member 5), a functional marker of adult corneal epithelial stem cells. These cells possess remarkable holoclone-forming capabilities, which can be suppressed by an antibody-mediated ABCB5 blockade. The cell sheets are generated from ABCB5 + hiPSCs that first emerge in 2D eye-like organoids around six weeks of differentiation and display corneal epithelial immunostaining characteristics and gene expression patterns, including sustained expression of ABCB5. The findings highlight the translational potential of ABCB5-enriched, hiPSC-derived corneal epithelial cell sheets to recover vision in stem cell-deficient human eyes and represent the first report of holoclone-forming stem cells being directly identified in an hiPSC-derived organoid., Competing Interests: M.H.F., B.R.K., and N.Y.F. are inventors or co-inventors of US and international patents assigned to Brigham and Women's Hospital, Boston Children's Hospital, the Massachusetts Eye and Ear Infirmary, and/or the VA Boston Healthcare System, Boston, MA, licensed to TICEBA GmbH (Heidelberg, Germany) and RHEACELL GmbH & Co. KG (Heidelberg, Germany). M.H.F. serves as a scientific advisor for TICEBA GmbH and RHEACELL GmbH & Co. KG., (© 2021 The Authors.)

The cancer stem cell (CSC) concept emerged from the recognition of inherent tumor heterogeneity and suggests that within a given tumor, in analogy to normal tissues, there exists a cellular hierarchy composed of a minority of more primitive cells with enhanced longevity (ie, CSCs) that give rise to shorter-lived, more differentiated cells (ie, cancer bulk populations), which on their own are not capable of tumor perpetuation. CSCs can be responsible for cancer therapeutic resistance to conventional, targeted, and immunotherapeutic treatment modalities, and for cancer progression through CSC-intrinsic molecular mechanisms. The existence of CSCs in colorectal cancer (CRC) was first established through demonstration of enhanced clonogenicity and tumor-forming capacity of this cell subset in human-to-mouse tumor xenotransplantation experiments and subsequently confirmed through lineage-tracing studies in mice. Surface markers for CRC CSC identification and their prospective isolation are now established. Therefore, the application of single-cell omics technologies to CSC characterization, including whole-genome sequencing, RNA sequencing, and epigenetic analyses, opens unprecedented opportunities to discover novel targetable molecular pathways and hence to develop novel strategies for CRC eradication. We review recent advances in this field and discuss the potential implications of next-generation CSC analyses for currently approved and experimental targeted CRC therapies., (Copyright © 2021. Published by Elsevier Inc.)

Background: While therapeutic success of the limbal tissue or cell transplantation to treat severe cases of limbal stem cell (LSC) deficiency (LSCD) strongly depends on the percentage of LSCs within the transplanted cells, prospective LSC enrichment has been hampered by the intranuclear localization of the previously reported LSC marker p63. The recent identification of the ATP-binding cassette transporter ABCB5 as a plasma membrane-spanning marker of LSCs that are capable of restoring the cornea and the development of an antibody directed against an extracellular loop of the ABCB5 molecule stimulated us to develop a novel treatment strategy based on the utilization of in vitro expanded allogeneic ABCB5 + LSCs derived from human cadaveric limbal tissue., Methods: We developed and validated a Good Manufacturing Practice- and European Pharmacopeia-conform production and quality-control process, by which ABCB5 + LSCs are derived from human corneal rims, expanded ex vivo, isolated as homogenous cell population, and manufactured as an advanced-therapy medicinal product (ATMP). This product was tested in a preclinical study program investigating the cells' engraftment potential, biodistribution behavior, and safety., Results: ABCB5 + LSCs were reliably expanded and manufactured as an ATMP that contains comparably high percentages of cells expressing transcription factors critical for LSC stemness maintenance (p63) and corneal epithelial differentiation (PAX6). Preclinical studies confirmed local engraftment potential of the cells and gave no signals of toxicity and tumorgenicity. These findings were sufficient for the product to be approved by the German Paul Ehrlich Institute and the U.S. Food & Drug Administration to be tested in an international multicenter phase I/IIa clinical trial (NCT03549299) to evaluate the safety and therapeutic efficacy in patients with LSCD., Conclusion: Building upon these data in conjunction with the previously shown cornea-restoring capacity of human ABCB5 + LSCs in animal models of LSCD, we provide an advanced allogeneic LSC-based treatment strategy that shows promise for replenishment of the patient's LSC pool, recreation of a functional barrier against invading conjunctival cells and restoration of a transparent, avascular cornea.

Background Aim: Mesenchymal stromal cells (MSCs) hold promise for the treatment of tissue damage and injury. However, MSCs comprise multiple subpopulations with diverse properties, which could explain inconsistent therapeutic outcomes seen among therapeutic attempts. Recently, the adenosine triphosphate-binding cassette transporter ABCB5 has been shown to identify a novel dermal immunomodulatory MSC subpopulation., Methods: The authors have established a validated Good Manufacturing Practice (GMP)-compliant expansion and manufacturing process by which ABCB5 + MSCs can be isolated from skin tissue and processed to generate a highly functional homogeneous cell population manufactured as an advanced therapy medicinal product (ATMP). This product has been approved by the German competent regulatory authority to be tested in a clinical trial to treat therapy-resistant chronic venous ulcers., Results: As of now, 12 wounds in nine patients have been treated with 5 × 10 5  autologous ABCB5 + MSCs per cm 2 wound area, eliciting a median wound size reduction of 63% (range, 32-100%) at 12 weeks and early relief of pain., Conclusions: The authors describe here their GMP- and European Pharmacopoeia-compliant production and quality control process, report on a pre-clinical dose selection study and present the first in-human results. Together, these data substantiate the idea that ABCB5 + MSCs manufactured as ATMPs could deliver a clinically relevant wound closure strategy for patients with chronic therapy-resistant wounds., (Copyright © 2020 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)