ABCB5+ dermal mesenchymal stromal cells with favorable skin homing and local immunomodulation for recessive dystrophic epidermolysis bullosa treatment.

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 IL2rgammanull (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.

Genes and compounds that increase type VII collagen expression as potential treatments for dystrophic epidermolysis bullosa.

Dystrophic epidermolysis bullosa (DEB) is a skin-blistering disease caused by mutations in COL7A1, which encodes type VII collagen (C7). There is no cure for DEB, but previous work has shown potential therapeutic benefit of increased production of even partially functional C7. Genome-wide screens using CRISPR-Cas9 have enabled the identification of genes involved in cancer development, drug resistance and other genetic diseases, suggesting that they could be used to identify drivers of C7 production. A keratinocyte C7 reporter cell line was created and used in a genome-wide CRISPR activation (CRISPRa) screen to identify genes and pathways that increase C7 expression. The CRISPRa screen results were used to develop a targeted drug screen to identify compounds that upregulate C7 expression. The C7_tdTomato cell line was validated as an effective reporter for detection of C7 upregulation. The CRISPRa screen identified DENND4B and TYROBP as top gene hits plus pathways related to calcium uptake and immune signalling in C7 regulation. The targeted drug screen identified several compounds that increase C7 expression in keratinocytes, of which kaempferol, a plant flavonoid, also significantly increased C7 mRNA and protein in DEB patient cells.

Role of transforming growth factor-ß1 in recessive dystrophic epidermolysis bullosa squamous cell carcinoma.

Squamous cell carcinoma (SCC) develops in more than 80% of individuals with the skin blistering disorder recessive dystrophic epidermolysis bullosa (RDEB). In contrast with UV-induced SCC, RDEB-SCC results from skin damage and has a high proliferative and metastatic rate with 5-year survival near zero. Our objective is to determine the mechanisms underlying the increased metastatic tendencies of RDEB-SCC. RDEB-SCC cultured cell lines were treated with RDEB and non-RDEB fibroblast conditioned media and assayed for migration and invasion with and without small molecule inhibitors for TGFß and other downstream signal transduction pathways. TGFß1 secreted by RDEB dermal fibroblasts has been found to induce migration and invasion and to increase expression of epithelial-to-mesenchymal transition markers in an RDEB-SCC line. These effects were reversed upon inhibition of TGFß signalling and its downstream pathways MEK/ERK, P38 kinase and SMAD3. A number of small molecule inhibitors for these pathways are in different phases of various clinical trials and may be applicable to RDEB-SCC patients. Studying the mechanisms of the extreme form RDEB-SCC may inform studies of other types of SCC, as well as lead to better therapies for RDEB patients.

Mating System Evolution under Strong Pollen Limitation: Evidence of Disruptive Selection through Male and Female Fitness in Clarkia xantiana.

Selection on floral traits in hermaphroditic plants is determined by both male and female reproductive success. However, predictions regarding floral trait and mating system evolution are often based solely on female fitness. Selection via male fitness has the potential to affect the outcomes of floral evolution. In this study, we used paternity analysis to assess individual selfing rates and selection on floral traits via male and female fitness in an experimental population of Clarkia xantiana where pollen limitation of seed set was strong. We detected selection through both female and male fitness with reinforcing or noninterfering patterns of selection through the two sex functions. For female fitness, selection favored reduced herkogamy and protandry, traits that promote increased autonomous selfing. For male fitness, selection on petal area was disruptive, with higher trait values conferring greater pollinator attraction and outcross siring success and smaller trait values leading to higher selfed siring success. Combining both female and male fitness, selection on petal area and protandry was disruptive because intermediate phenotypes were less successful as both males and females. Finally, functional relationships among male and female fertility components indicated that selfing resulted in seed discounting and pollen discounting. Under these functional relationships, the evolutionarily stable selfing rate can be intermediate or predominantly selfing or outcrossing, depending on the segregating load of deleterious mutations.

Sociodemographic Differences in Clients Preferring Video-Call Over In-person Interview: A Pilot Study of HIV Tele-partner Services.

The New York City Department of Health Disease Intervention Specialists (DIS) routinely contact newly HIV-diagnosed persons via telephone calls and in-person meetings to conduct partner services (PS) interviews in order to elicit the names and contact information of the HIV-exposed partners for notification and HIV-testing, and to assist clients with linkage to care. From October 2013 to December 2015, we offered PS interviews conducted via video-call alongside voice-call and in-person modes in a selected geographic area of NYC. PS interviews were conducted according to the clients' preferred mode (in-person, voice- or video-call) and location (health care facility, clients' residences, or other NYC locations). At the conclusion of the PS interviews, DIS elicited responses from persons interviewed via video-call on their perception, satisfaction and personal experiences using video-call for public health and personal purposes. Acceptance and satisfaction with PS interviews via video-call were high among clients aged <30 years, men who have sex with men, or with education above high school; while PS yields were similar across modes. These results provide evidence of the potential effectiveness of video-call interviews for specific populations.

The effect of HIV field-based testing on the proportion of notified partners who test for HIV in New York City.

HIV partner services can effectively reach populations with high HIV prevalence. However, located and notified sex and needle-sharing partners of persons infected with HIV often fail to test. Field testing may increase the proportion of notified partners who test for HIV. In 2008, New York City's health department incorporated field testing into partner services. After the introduction of field testing, the proportion of notified partners who tested for HIV rose from 52% to 76% (P<.001). HIV prevalence fell slightly among notified partners who accepted testing (12% to 9%, P=.82), but we identified more than double the number of new positives (11 vs 25). All positive and 97% of negative results were received by the person tested.