Cutaneous wounds heal more slowly in elderly males than in elderly females, suggesting a role for sex hormones in the healing process. Indeed, androgen/androgen receptor (AR) signaling has been shown to inhibit cutaneous wound healing. AR is expressed in several cell types in healing skin, including keratinocytes, dermal fibroblasts, and infiltrating macrophages, but the exact role of androgen/AR signaling in these different cell types remains unclear. To address this question, we generated and studied cutaneous wound healing in cell-specific AR knockout (ARKO) mice. General and myeloid-specific ARKO mice exhibited accelerated wound healing compared with WT mice, whereas keratinocyte-and fibroblast-specific ARKO mice did not. Importantly, the rate of wound healing in the general ARKO mice was dependent on AR and not serum androgen levels. Interestingly, although dispensable for wound closure, keratinocyte AR promoted re-epithelialization, while fibroblast AR suppressed it. Further analysis indicated that AR suppressed wound healing by enhancing the inflammatory response through a localized increase in TNF-α expression. Furthermore, AR enhanced local TNF-α expression via multiple mechanisms, including increasing the inflammatory monocyte population, enhancing monocyte chemotaxis by upregulating CCR2 expression, and enhancing TNF-α expression in macrophages. Finally, targeting AR by topical application of a compound (ASC-J9) that degrades AR protein resulted in accelerated healing, suggesting a potential new therapeutic approach that may lead to better treatment of wound healing.

Upon insult, such as infection or tissue injury, the innate and adaptive immune systems initiate a series of responses to defend the body. Recent studies from immune cell-specific androgen receptor (AR) knockout mice demonstrated that androgen and its receptor (androgen/AR) play significant roles in both immune regulations. In the innate immunity, androgen/AR is required for generation and proper function of neutrophils; androgen/AR also regulates wound healing processes through macrophage recruitment and proinflammatory cytokine production. In adaptive immunity, androgen/AR exerts suppressive effects on development and activation of T and B cells. Removal of such suppression causes thymic enlargement and excessive export of immature B cells. Altogether, androgen/AR plays distinct roles in individual immune cells, and targeting androgen/AR may help in treatment and management of immune-related diseases.

To differentiate roles of androgen receptor (AR) in prostate stromal and epithelial cells, we have generated inducible-(ind)ARKO-TRAMP and prostate epithelial-specific ARKO TRAMP (pes-ARKO-TRAMP) mouse models, in which the AR was knocked down in both prostate epithelium and stroma or was knocked out in the prostate epithelium, respectively. We found that loss of AR in both mouse models resulted in poorly differentiated androgen deprivation therapy ͉ testosterone ͉ TRAMP

Neutrophils, the major phagocytes that form the first line of cell-mediated defense against microbial infection, are produced in the bone marrow and released into the circulation in response to granulocyte-colony stimulating factor (G-CSF). Here, we report that androgen receptor knockout (ARKO) mice are neutropenic and susceptible to acute bacterial infection, whereas castration only results in moderate neutrophil reduction in mice and humans. Androgen supplement can restore neutrophil counts via stabilizing AR in castrated mice, but not in ARKO and testicular feminization mutant (Tfm) mice. Our results show that deletion of the AR gene does not influence myeloid lineage commitment, but significantly reduces the proliferative activity of neutrophil precursors and retards neutrophil maturation. CXCR2-dependent migration is also decreased in ARKO neutrophils as compared with wild-type controls. G-CSF is unable to delay apoptosis in ARKO neutrophils, and ARKO mice show a poor granulopoietic response to exogenous G-CSF injection. In addition, AR can restore G-CSF–dependent granulocytic differentiation upon transduction into ARKO progenitors. We further found that AR augments G-CSF signaling by activating extracellular signal-regulated kinase 1/2 and also by sustaining Stat3 activity via diminishing the inhibitory binding of PIAS3 to Stat3. Collectively, our findings demonstrate an essential role for AR in granulopoiesis and host defense against microbial infection.

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays important roles for prostate cancer cell survival, and the androgen receptor (AR) plays essential roles for prostate cancer cell proliferation. How these two signals cooperate to control cell growth and death, however, remains unclear and debated. Here we provide the first linkage by the identification of Forkhead transcription factor FOXO3a, the PI3K/Akt downstream substrate, as a positive regulator for the induction of AR gene expression. Both Western blot and real time PCR assays demonstrate that FOXO3a can induce AR expression at the protein and mRNA levels, and gel shift and chromatin immunoprecipitation assays further demonstrate that FOXO3a can induce 5 AR promoter activity via binding to the consensus DNA-binding sequence in the AR 5 promoter ؊1290 to ؊1297 (5-TTGTTTCA-3). Under normal growth conditions, blocking PI3K/Akt signals by LY294002 causes LNCaP cell arrest in G 1 phase rather than apoptosis. However, further blocking of AR functions by AR small interfering RNA leads to dramatic LNCaP cell death, suggesting that AR may play important protective roles when the PI3K/Akt signal pathway is blocked by LY294002. Together, our data provide the first model to explain how PI3K/Akt and AR can cooperate to control LNCaP cell growth and death under normal conditions. Prostate cancer (PCa) 3 is one of the most frequently diagnosed malignancies and is the second leading cause of cancer deaths among American men (1). Androgen and the androgen receptor (AR) (2-4) play important roles in this malignancy, and androgen ablation has been the main therapeutic option for the treatment of locally advanced or metastatic PCa. The AR is a member of the nuclear receptor superfamily that is composed of a variable NH 2 -terminal domain, a highly conserved DNA-binding domain, a hinge domain, and a ligand-binding domain. Although the functional significance of the androgen-AR signaling pathway in PCa progression is well studied, regulation of AR gene expression and its potential linkage to PCa progression remains largely unknown.The FOXO subfamily of Forkhead transcription factors, FOXO1 (FKHR), FOXO3a (FKHRL1), and FOXO4 (AFX), is regulated by the PI3K/Akt pathway. Direct phosphorylation of FOXO proteins by Akt results in cytoplasmic retention and the inactivation of FOXOs, inhibiting the expression of FOXO-regulated genes, which control diverse functions, including cell differentiation, proliferation, cell death, metabolism, and longevity (5). In tumor cells, in vitro studies found that the induction of apoptosis and cell cycle arrest by FOXOs through regulating target genes like p27 KIP , cyclin D, FasL, and BIM depends on cell types and physiological conditions (6, 7). A study found that FOXO3a induces apoptosis in LAPC4 prostate cancer cells via the up-regulation of its direct target tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) (8). Also, FOXOs play a complex role in tumorigenesis (7).In tumor cells Akt is often constitutively activated eithe...

Androgen and the androgen receptor (AR) have been shown to play critical roles in male fertility. Our previous data demonstrated that mice lacking AR (AR(-/y)) revealed incomplete germ cell development and lowered serum testosterone levels, which resulted in azoospermia and infertility. However, the consequences of AR loss in Leydig cells remain largely unknown. Using a Cre-LoxP conditional knockout strategy, we generated a tissue-specific knockout mouse (L-AR(-/y)) with the AR gene deleted by the anti-Müllerian hormone receptor-2 (Amhr2) promoter driven Cre expressed in Leydig cells. Phenotype analyses show that the outside appearance of L-AR(-/y) mice was indistinguishable from wild type mice (AR(+/y)), but with atrophied testes and epididymis. L-AR(-/y) mice were infertile, with spermatogenic arrest predominately at the round spermatid stage and no sperm could be detected in the epididymis. L-AR(-/y) mice also have lower serum testosterone concentrations and higher serum leuteinizing hormone and follicle-stimulating hormone concentrations than AR(+/y) mice. Further mechanistic studies demonstrated that hypotestosteronemia in L-AR(-/y) mice is not caused by reducing numbers of Leydig cells, but instead by the alterations of several key steroidogenic enzymes, including 17beta-HSD3, 3beta-HSD6, and P450c17. Together, L-AR(-/y) mice provide in vivo evidence that functional AR in Leydig cells is essential to maintain normal spermatogenesis, testosterone production, and required for normal male fertility.

Leber congenital amaurosis (LCA) is an autosomal recessive retinal dystrophy that manifests with genetic heterogeneity. We sequenced the exome of an individual with LCA and identified nonsense (c.507G>A, p.Trp169*) and missense (c.769G>A, p.Glu257Lys) mutations in NMNAT1, which encodes an enzyme in the nicotinamide adenine dinucleotide (NAD) biosynthesis pathway implicated in protection against axonal degeneration. We also found NMNAT1 mutations in ten other individuals with LCA, all of whom carry the p.Glu257Lys variant.

Vascular invasion provides a direct route for tumor metastasis. The degree to which microRNA (miRNA) expression plays a role in tumor vascular invasion is unclear. Here, we report that miR-494 is up-regulated in human hepatocellular carcinoma (HCC) tumors with vascular invasion and can promote HCC cell invasiveness by gene inactivation of multiple invasion-suppressor miRNAs. Our results show that ten eleven translocation (TET) methylcytosine dioxygenase, predominantly TET1 in HCC cells, is a direct target of miR-494. The reduced 5′-hydroxymethylcytosine levels observed in the proximal cytosine-phosphate-guanine (CpG) regions of multiple invasion-suppressor miRNA genes are strongly associated with their transcriptional repression upon miR-494 overexpression, whereas enforced DNA demethylation can abolish the repression. Furthermore, TET1 knockdown shows a similar effect as miR-494 overexpression. Conversely, miR-494 inhibition or enforced TET1 expression is able to restore invasion-suppressor miRNAs and inhibit miR-494-mediated HCC cell invasion. Conclusions: miR-494 can trigger gene silencing of multiple invasion-suppressor miRNAs by inhibiting genomic DNA demethylation by direct targeting of TET1, thereby leading to tumor vascular invasion. (Hepatology 2015;62:466–480