Clinical stage drugs targeting inhibitor of apoptosis proteins purge episomal Hepatitis B viral genome in preclinical models

A major unmet clinical need is a therapeutic capable of removing hepatitis B virus (HBV) genome from the liver of infected individuals to reduce their risk of developing liver cancer. A strategy to deliver such a therapy could utilize the ability to target and promote apoptosis of infected hepatocytes. Presently there is no clinically relevant strategy that has been shown to effectively remove persistent episomal covalently closed circular HBV DNA (cccDNA) from the nucleus of hepatocytes. We used linearized single genome length HBV DNA of various genotypes to establish a cccDNA-like reservoir in immunocompetent mice and showed that clinical-stage orally administered drugs that antagonize the function of cellular inhibitor of apoptosis proteins can eliminate HBV replication and episomal HBV genome in the liver. Primary human liver organoid models were used to confirm the clinical relevance of these results. This study underscores a clinically tenable strategy for the potential elimination of chronic HBV reservoirs in patients.

Sulforaphane Protects Against Ethanol-Induced Apoptosis in Human Neural Crest Cells Through Diminishing Ethanol-Induced Hypermethylation at the Promoters of the Genes Encoding the Inhibitor of Apoptosis Proteins

The neural crest cell (NCC) is a multipotent progenitor cell population that is sensitive to ethanol and is implicated in the Fetal Alcohol Spectrum Disorders (FASD). Studies have shown that sulforaphane (SFN) can prevent ethanol-induced apoptosis in NCCs. This study aims to investigate whether ethanol exposure can induce apoptosis in human NCCs (hNCCs) through epigenetically suppressing the expression of anti-apoptotic genes and whether SFN can restore the expression of anti-apoptotic genes and prevent apoptosis in ethanol-exposed hNCCs. We found that ethanol exposure resulted in a significant increase in the expression of DNMT3a and the activity of DNMTs. SFN treatment diminished the ethanol-induced upregulation of DNMT3a and dramatically reduced the activity of DNMTs in ethanol-exposed hNCCs. We also found that ethanol exposure induced hypermethylation at the promoter regions of two inhibitor of apoptosis proteins (IAP), NAIP and XIAP, in hNCCs, which were prevented by co-treatment with SFN. SFN treatment also significantly diminished ethanol-induced downregulation of NAIP and XIAP in hNCCs. The knockdown of DNMT3a significantly enhanced the effects of SFN on preventing the ethanol-induced repression of NAIP and XIAP and apoptosis in hNCCs. These results demonstrate that SFN can prevent ethanol-induced apoptosis in hNCCs by preventing ethanol-induced hypermethylation at the promoter regions of the genes encoding the IAP proteins and diminishing ethanol-induced repression of NAIP and XIAP through modulating DNMT3a expression and DNMT activity.

Inhibitor of apoptosis proteins 1 and 2 are required for the homeostasis of murine RORγt+ γδ T cells

RORγt+ γδ T cells, known as γδT17, are an innate-like subset of T cells that produce interleukin (IL)-17A and initiate type 3 immune responses during infections or autoimmune pathologies. Herein we show that the cellular inhibitor of apoptosis proteins cIAP1 and 2 are required for the peripheral homeostasis of γδT17 but not for their thymic development. γδT17 cells that were deficient in both cIAP1 and 2 were profoundly reduced in the peripheral lymph nodes and skin. Likewise, both RORγt+ innate lymphoid cells (ILC3) and RORγt+ Tbet+ γδ T cells were reduced in the lamina propria of adult mice. Further, cIAP1 and 2 were required for the expression of the transcription factors RORγt and cMAF in γδT17 cells during neonatal and adult life. Single deficiency of either cIAP1 or 2 did not affect the homeostasis or transcription factor profile of γδT17 cells. Moreover, bone marrow reconstitutions and transfer of neonatal γδ T cells to RAG1−/− hosts showed that both intrinsic and extrinsic factors contribute to the loss of γδT17 cells in cIAP1/2 double deficient mice, while only extrinsic signals were responsible for the decrease of ILC3 cells. Deficiency of γδT17 cells in cIAP1 and cIAP2 double deficient animals, or the presence of functionally defective γδT17 cells did not confer protection against IMQ-induced psoriasis. Collectively, our data reveal a previously undescribed role for cIAP1 and cIAP2 in the homeostasis of γδT17 and ILC3 cells.