Androgens play pivotal roles in the regulation of male development and physiological processes, particularly in the male reproductive system. Most biological effects of androgens are mediated by the ...action of nuclear androgen receptor (AR). AR acts as a master regulator of downstream androgen-dependent signaling pathway networks. This ligand-dependent transcriptional factor modulates gene expression through the recruitment of various coregulator complexes, the induction of chromatin reorganization, and epigenetic histone modifications at target genomic loci. Dysregulation of androgen/AR signaling perturbs normal reproductive development and accounts for a wide range of pathological conditions such as androgen-insensitive syndrome, prostate cancer, and spinal bulbar muscular atrophy. In this review we summarize recent advances in understanding of the epigenetic mechanisms of AR action as well as newly recognized aspects of AR-mediated androgen signaling in both men and women. In addition, we offer a perspective on the use of animal genetic model systems aimed at eventually developing novel therapeutic AR ligands.
Purpose: To investigate if balloon angioplasty with a prolonged inflation time (>3 minutes) can prevent postdilation dissection in femoropopliteal lesions. Methods: A retrospective single-center ...analysis examined 294 consecutive patients (mean age 74.1±8.7 years; 215 men) with de novo femoropopliteal lesions treated with balloon angioplasty between 2013 and 2018. The patients were classified into 2 groups to compare angiographic dissection patterns: 175 patients treated with balloon angioplasty for 3 minutes (3-minute group) and 119 treated for >3 minutes (>3-minute group). Results: Mean balloon inflation time was 7.8±2.7 minutes in the >3-minute group. Severe dissections (type C or higher) were observed less frequently after balloon dilation in the >3-minute group (22.7% vs 50.9%, p<0.001); therefore, significantly more patients in the >3-minute group had successful endovascular treatment after initial balloon angioplasty (57.1% vs 38.3%, p=0.001). Additional balloon dilation was attempted more frequently in the 3-minute group (30.9% vs 14.3%, p=0.001); as a result, there were more patients in whom additional balloon dilation repaired severe dissection that occurred after the initial dilation (25.1% vs 10.9%, p=0.001). Multivariate analysis revealed that chronic total occlusion (p<0.001) and longer lesion (p<0.001) were independent predictors of severe dissection, and prolonged dilation time was independently related to preventing severe dissection (p<0.001). Among 171 patients undergoing successful balloon angioplasty without stent implantation, the Kaplan-Meier estimates of primary patency within 1 year did not differ significantly according to inflation time. Conclusion: Balloon dilation with prolonged inflation time (>3 minutes) may be effective as an initial strategy to prevent severe dissection in femoropopliteal lesions compared to inflation for 3 minutes.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Bone remodeling is characterized by the sequential, local tethering of osteoclasts and osteoblasts and is key to the maintenance of bone integrity. While bone matrix-mobilized growth factors, such as ...TGF-β, are proposed to regulate remodeling, no in vivo evidence exists that an osteoclast-produced molecule serves as a coupling factor for bone resorption to formation. We found that CTHRC1, a protein secreted by mature bone-resorbing osteoclasts, targets stromal cells to stimulate osteogenesis. Cthrc1 expression was robustly induced when mature osteoclasts were placed on dentin or hydroxyapatite, and also by increasing extracellular calcium. Cthrc1 expression in bone increased in a high-turnover state (such as that induced by RANKL injections in vivo), but decreased in conditions associated with suppressed bone turnover (such as with aging and after alendronate treatment). Targeted deletion of Cthrc1 in mice eliminated Cthrc1 expression in bone, whereas its deficiency in osteoblasts did not exert any significant effect. Osteoclast-specific deletion of Cthrc1 resulted in osteopenia due to reduced bone formation and impaired the coupling process after resorption induced by RANKL injections, impairing bone mass recovery. These data demonstrate that CTHRC1 is an osteoclast-secreted coupling factor that regulates bone remodeling.
The vitamin D receptor (VDR) is a nuclear receptor for the active form of vitamin D3 and also for the secondary bile acid lithocholic acid (LCA). The in vivo role of VDR in bile acid metabolism ...remains largely uncharacterized. We previously reported that pharmacological VDR activation enhances urinary bile acid excretion, particularly in mice fed chow supplemented with chenodeoxycholic acid (CDCA), which is metabolized to muricholic acid in mouse liver and is also converted to LCA by intestinal bacteria. In this study, we examined the effect of VDR deletion on bile acid composition utilizing VDR-knockout (VDR-KO) mice. VDR deletion did not change total bile acid levels in liver or feces of mice when fed standard chow supplemented with calcium, needed to prevent hypocalcemia in VDR-KO mice. Total bile acid levels in plasma and urine tended to be higher and lower, respectively, in VDR-KO mice. After feeding CDCA-supplemented chow, VDR-KO mice showed decreased hepatic, fecal and urinary total bile acid and CDCA levels compared to wild-type mice. Plasma total bile acids and LCA were relatively high in these mice. These results indicate that VDR deletion influences CDCA metabolism. VDR may play a role in the excretion of excess bile acids.
Cytoskeletal reorganization in osteoclasts to form actin rings is necessary for these cells to attach to bone and resorb bone matrices. We delineated the pathway through which Wnt5a signaling through ...receptor tyrosine kinase-like orphan receptor 2 (Ror2) promoted the bone-resorbing activity of osteoclasts. Wnt5a binding to Ror2 stimulated Rho, a small GTPase involved in cytoskeletal reorganization. Subsequently, the Rho effector kinase Pkn3 bound to and enhanced the activity of c-Src, a nonreceptor tyrosine kinase that is critical for actin ring formation. Mice with an osteoclast-specific deficiency in
(
) had increased bone mass. Osteoclasts derived from these mice exhibited impaired bone resorption and actin ring formation, defects that were rescued by overexpression of constitutively active RhoA. These osteoclasts also exhibited reduced interaction between c-Src and Pkn3 and reduced c-Src kinase activity. Similar to
mice, mice with a global deficiency of
(
) had increased bone mass. The proline-rich region and kinase domain of Pkn3 were required to restore the bone-resorbing activity of osteoclasts derived from
mice. Thus, Pkn3 promotes bone resorption downstream of Wnt5a-Ror2-Rho signaling, and this pathway may be a therapeutic target for bone diseases such as osteoporosis, rheumatoid arthritis, and periodontal disease.
With advancement in the treatment options of rheumatoid arthritis (RA), optimising the outcomes of difficult-to-treat patients has become increasingly important in clinical practice. In particular, ...insensitivity to first-line biologic disease-modifying anti-rheumatic drugs (bDMARD) is becoming a significant problem because it may decrease the treatment adherence of patients. This study aimed to compare RA patients with an insensitivity and those with a poor response to initial treatment with tumour necrosis factor inhibitors (TNFis), which are the most frequently used bDMARDs.
This is a retrospective cohort study using clinical data from the FIRST registry. bDMARD-naïve RA patients treated with tumour necrosis factor inhibitors (TNFis) from August 2003 to May 2019 were included and categorised into three groups: TNFi insensitivity, poor response to TNFis and controls. TNFi insensitivity was defined as follows: (1) discontinuation of TNFi treatment within 22 weeks due to lack of any response, or (2) an increase in the disease activity score in 28 joints-C-reactive protein (DAS28-CRP) of > 0.6 at week 22 compared with week 0. Among the remaining patients, those with a DAS28-CRP > 2.6 at week 22 were categorised in the poor response group.
Of the included patients, 94 were classified in the insensitivity, 604 in the poor response and 915 in the control. A higher DAS28-CRP before treatment was a risk factor for a poor response but not for insensitivity. In contrast, dose escalation of infliximab decreased the risk of a poor response but not that of insensitivity.
In future research, poor and insensitivity to bDMARDs should be assessed separately to fully elucidate the aetiology of, and risk factors for, bDMARD refractoriness.
We have demonstrated that cytokine thymic stromal lymphopoietin (TSLP), whose expression is rapidly induced upon keratinocyteselective ablation of retinoid X receptors (RXRs) -α and -β in the mouse ...($RXR\alpha\beta^{ep-/-} mice$), plays a key role in initiating a skin and systemic atopic dermatitis-like phenotype. We show here that topical application of the physiologically active ligand lα,25(OH)₂D₃; calcitriol of the vitamin D receptor, or of its low-calcemic analog MC903 (calcipotriol; Dovonex), induces TSLP expression in epidermal keratinocytes, which results in an atopic dermatitis-like syndrome mimicking that seen in $RXR\alpha\beta^{ep-/-}$ mutants and transgenic mice overexpressing TSLP in keratinocytes. Furthermore, topical application of retinoic acid receptor RARγ-selective agonist BMS961 also induces TSLP expression either on its own or synergistically with lα,25-(OH)₂D₃. Our data demonstrate that RXR/ vitamin D receptor and RXR/retinoic acid receptor-γ heterodimers and their ligands cell-autonomously control the expression of TSLP in epidermal keratinocytes of the mouse. We propose molecular mechanisms through which vitamin D3 and retinoic acid signalings could be involved in the pathogenesis of atopic diseases.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The arylhydrocarbon receptor (AhR) mediates the adverse effects of dioxins, including modulation of sex steroid hormone signaling. The role of AhR as a transcription factor is well described. AhR ...regulates the expression of target genes such as CYP1A1; however, the mechanisms of AhR function through other target-selective systems remain elusive. Accumulating evidence suggests that AhR modulates the functions of other transcription factors. The ligand-activated AhR directly associates with estrogen or androgen receptors (ERα or AR) and modulates their function both positively and negatively. This may, in part explain the sex steroid hormone-related adverse effects of dioxins. AhR has recently been shown to promote the proteolysis of ERα/AR through assembling a ubiquitin ligase complex, CUL4B
AhR. In the CUL4B
AhR complex, AhR acts as a substrate-recognition subunit to recruit ERα/AR. This action defines a novel role for AhR as a ligand-dependent E3 ubiquitin ligase. We propose that target-specific regulation of protein destruction, as well as gene expression, is modulated by environmental toxins through the E3 ubiquitin ligase activity of AhR.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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