Epigenetic switch reshapes epithelial progenitor cell signatures and drives inflammatory pathogenesis in hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a complex inflammatory skin disease with undefined mechanistic underpinnings. Here, we investigated HS epithelial cells and demonstrated that HS basal progenitors modulate their lineage restriction and give rise to pathogenic keratinocyte clones, resulting in epidermal hyperproliferation and dysregulated inflammation in HS. When comparing to healthy epithelial stem/progenitor cells, in HS, we identified changes in gene signatures that revolve around the mitotic cell cycle, DNA damage response and repair, as well as cell-cell adhesion and chromatin remodeling. By reconstructing cell differentiation trajectory and CellChat modeling, we identified a keratinocyte population specific to HS. This population is marked by S100A7/8/9 and KRT6 family members, triggering IL1, IL10, and complement inflammatory cascades. These signals, along with HS-specific proinflammatory cytokines and chemokines, contribute to the recruitment of certain immune cells during the disease progression. Furthermore, we revealed a previously uncharacterized role of S100A8 in regulating the local chromatin environment of target loci in HS keratinocytes. Through the integration of genomic and epigenomic datasets, we identified genome-wide chromatin rewiring alongside the switch of transcription factors (TFs), which mediated HS transcriptional profiles. Importantly, we identified numerous clinically relevant inflammatory enhancers and their coordinated TFs in HS basal CD49fhigh cells. The disruption of the S100A enhancer using the CRISPR/Cas9-mediated approach or the pharmacological inhibition of the interferon regulatory transcription factor 3 (IRF3) efficiently reduced the production of HS-associated inflammatory regulators. Our study not only uncovers the plasticity of epidermal progenitor cells in HS but also elucidates the epigenetic mechanisms underlying HS pathogenesis.

Advances in molecular pathogenesis of hidradenitis suppurativa: Dysregulated keratins and ECM signaling.

Hidradenitis suppurativa (HS) is characterized by deep-seated, highly inflamed, and painful lumps/abscesses, fistulae, and sinus tracts that grow extensively deep in the dermis and are highly immunogenic in nature. In about one-third of the HS patients there is strong evidence for the role of γ-secretase mutations along with dysregulated Notch signaling. However, the contribution of dysregulated Notch signaling in HS pathogenesis in relation to hair follicle alterations and hyper-activation of the immune system remains undefined. A genome-wide association study (GWAS), proteomic data and functional investigations of identified sequence variants in HS pathology are not fully revealing. The disease initiation or progression may involve bacterial infection besides intrinsic functional defects in keratinocytes, which may be key to further exacerbate immune cell infiltration and cytokine production in and around the lesional tissue. The absence of a suitable animal model that could fully recapitulate the pathogenesis of HS is a major impediment for proper understanding the underlying mechanisms and development of effective treatments. The presence of extracellular matrix (ECM) degradation products along with dysregulation in keratinocytes and, dermal fibroblasts ultimately affect immune regulation and are various components of HS pathogenesis. Bacterial infection further exacerbates the complexity of the disease progression. While anti-TNFα therapy shows partial efficacy, treatment to cure HS is absent. Multiple clinical trials targeting various cytokines, complement C5a and ECM products are in progress. This review provides state-of-the-art information on these aspects with a focus on dysregulated keratinocyte and immune cells; and role of ECM, and Keratin functions in this regard.

Epigenetic regulation in the pathogenesis of non-melanoma skin cancer.

Understanding of cancer with the help of ever-expanding cutting edge technological tools and bioinformatics is revolutionizing modern cancer research by broadening the space of discovery window of various genomic and epigenomic processes. Genomics data integrated with multi-omics layering have advanced cancer research. Uncovering such layers of genetic mutations/modifications, epigenetic regulation and their role in the complex pathophysiology of cancer progression could lead to novel therapeutic interventions. Although a plethora of literature is available in public domain defining the role of various tumor driver gene mutations, understanding of epigenetic regulation of cancer is still emerging. This review focuses on epigenetic regulation association with the pathogenesis of non-melanoma skin cancer (NMSC). NMSC has higher prevalence in Caucasian populations compared to other races. Due to lack of proper reporting to cancer registries, the incidence rates for NMSC worldwide cannot be accurately estimated. However, this is the most common neoplasm in humans, and millions of new cases per year are reported in the United States alone. In organ transplant recipients, the incidence of NMSC particularly of squamous cell carcinoma (SCC) is very high and these SCCs frequently become metastatic and lethal. Understanding of solar ultraviolet (UV) light-induced damage and impaired DNA repair process leading to DNA mutations and nuclear instability provide an insight into the pathogenesis of metastatic neoplasm. This review discusses the recent advances in the field of epigenetics of NMSCs. Particularly, the role of DNA methylation, histone hyperacetylation and non-coding RNA such as long-chain noncoding (lnc) RNAs, circular RNAs and miRNA in the disease progression are summarized.

Cutaneous Exposure to Arsenicals Is Associated with Development of Constrictive Bronchiolitis in Mice.

Organoarsenicals, such as lewisite and related chloroarsine, diphenylchloroarsine (DPCA), are chemical warfare agents developed during World War I. Stockpiles in Eastern Europe remain a threat to humans. The well-documented effects of cutaneous exposure to these organoarsenicals include skin blisters, painful burns, and life-threatening conditions such as acute respiratory distress syndrome. In survivors, long-term effects such as the development of respiratory ailments are reported for the organoarsenical sulfur mustard; however, no long-term pulmonary effects are documented for lewisite and DPCA. No animal models exist to explore the relationship between skin exposure to vesicants and constrictive bronchiolitis. We developed and characterized a mouse model to study the long-term effects of cutaneous exposure on the lungs after exposure to a sublethal dose of organoarsenicals. We exposed mice to lewisite, DPCA, or a less toxic surrogate organoarsenic chemical, phenyl arsine oxide, on the skin. The surviving mice were followed for 20 weeks after skin exposure to arsenicals. Lung microcomputed tomography, lung function, and histology demonstrated increased airway resistance, increased thickness of the smooth muscle layer, increased collagen deposition in the subepithelium, and peribronchial lymphocyte infiltration in mice exposed to arsenical on skin.

Pulmonary pathogenesis in a murine model of inhaled arsenical exposure.

Arsenic trioxide (ATO), an inorganic arsenical, is a toxic environmental contaminant. It is also a widely used chemical with industrial and medicinal uses. Significant public health risk exists from its intentional or accidental exposure. The pulmonary pathology of acute high dose exposure is not well defined. We developed and characterized a murine model of a single inhaled exposure to ATO, which was evaluated 24 h post-exposure. ATO caused hypoxemia as demonstrated by arterial blood-gas measurements. ATO administration caused disruption of alveolar-capillary membrane as shown by increase in total protein and IgM in the bronchoalveolar lavage fluid (BALF) supernatant and an onset of pulmonary edema. BALF of ATO-exposed mice had increased HMGB1, a damage-associated molecular pattern (DAMP) molecule, and differential cell counts revealed increased neutrophils. BALF supernatant also showed an increase in protein levels of eotaxin/CCL-11 and MCP-3/CCL-7 and a reduction in IL-10, IL-19, IFN-γ, and IL-2. In the lung of ATO-exposed mice, increased protein levels of G-CSF, CXCL-5, and CCL-11 were noted. Increased mRNA levels of TNF-a, and CCL2 in ATO-challenged lungs further supported an inflammatory pathogenesis. Neutrophils were increased in the blood of ATO-exposed animals. Pulmonary function was also evaluated using flexiVent. Consistent with an acute lung injury phenotype, respiratory and lung elastance showed significant increase in ATO-exposed mice. PV loops showed a downward shift and a decrease in inspiratory capacity in the ATO mice. Flow-volume curves showed a decrease in FEV0.1 and FEF50. These results demonstrate that inhaled ATO leads to pulmonary damage and characteristic dysfunctions resembling ARDS in humans.

BDNF overexpression in the bladder induces neuronal changes to mediate bladder overactivity.

Elevated levels of brain-derived neurotrophic factor (BDNF) in urine of overactive bladder (OAB) patients support the association of BDNF with OAB symptoms, but the causality is not known. Here, we investigated the functionality of BDNF overexpression in rat bladder following bladder wall transfection of either BDNF or luciferase (luciferase) transgenes (10 µg). One week after transfection, BDNF overexpression in bladder tissue and elevation of urine BDNF levels were observed together with increased transcript of BDNF, its cognate receptors (TrkB and p75NTR), and downstream PLCγ isoforms in bladder. BDNF overexpression can induce the bladder overactivity (BO) phenotype which is demonstrated by the increased voiding pressure and reduced intercontractile interval during transurethral open cystometry under urethane anesthesia. A role for BDNF-mediated enhancement of prejunctional cholinergic transmission in BO is supported by the significant increase in the atropine- and neostigmine-sensitive component of nerve-evoked contractions and upregulation of choline acetyltransferase, vesicular acetylcholine transporter, and transporter Oct2 and -α1 receptors. In addition, higher expression of transient receptor channels (TRPV1 and TRPA1) and pannexin-1 channels in conjunction with elevation of ATP and neurotrophins in bladder and also in L6/S1 dorsal root ganglia together support a role for sensitized afferent nerve terminals in BO. Overall, genomic changes in efferent and afferent neurons of bladder induced by the overexpression of BDNF per se establish a mechanistic link between elevated BDNF levels in urine and dysfunctional voiding observed in animal models and in OAB patients.

Molecular correlates in urine for the obesity and prostatic inflammation of BPH/LUTS patients.

PURPOSE: Benign prostatic hyperplasia (BPH) is strongly associated with obesity and prostatic tissue inflammation, but the molecular underpinning of this relationship is not known. Here, we examined the association between urine levels of chemokines/adipokines with histological markers of prostate inflammation, obesity, and lower urinary tract symptoms LUTS in BPH patients. METHODS: Frozen urine specimens from 207 BPH/LUTS patients enrolled in Nashville Men's Health Study were sent for blinded analysis of 11 analytes, namely sIL-1RA, CXC chemokines (CXCL-1, CXCL-8, CXCL-10), CC chemokines (CCL2, CCL3, CCL5), PDGF-BB, interleukins IL-6, IL-17, and sCD40L using Luminex™ xMAP® technology. After adjusting for age and medication use, the urine levels of analytes were correlated with the scales of obesity, prostate inflammation grade, extent, and markers of lymphocytic infiltration (CD3 and CD20) using linear regression. RESULTS: sIL-1RA levels were significantly raised with higher BMI, waist circumference and waist-hip ratio in BPH patients after correction for multiple testing (P = 0.02). Men with greater overall extent of inflammatory infiltrates and maximal CD3 infiltration were marginally associated with CXCL-10 (P = 0.054) and CCL5 (P = 0.054), respectively. CCL3 in 15 patients with moderate to severe grade inflammation was marginally associated with maximal CD20 infiltration (P = 0.09), whereas CCL3 was undetectable in men with mild prostate tissue inflammation. There was marginal association of sCD40L with AUA-SI scores (P = 0.07). CONCLUSIONS: Strong association of sIL-1RA in urine with greater body size supports it as a major molecular correlate of obesity in the urine of BPH patients. Increased urine levels of CXCL-10, CCL5, and CCL3 were marginally associated with the scores for prostate tissue inflammation and lymphocytic infiltration. Overall, elevated urinary chemokines support that BPH is a metabolic disorder and suggest a molecular link between BPH/LUTS and prostatic inflammation.

MicroRNAs as potential biomarkers to predict the risk of urinary retention following intradetrusor onabotulinumtoxin-A injection.

AIMS: MicroRNAs (miRs) control post-transcriptional gene expression, and this is relevant in understanding better chronic diseases and treatment outcomes. The role of miRs in the pathology and treatment outcomes of overactive bladder (OAB) is unknown. In this study, we assessed the differential expression of miRs in OAB patients responding with either normal or elevated post-void residual volumes (PVRs) ≥200 mL following intradetrusor injection of onabotulinumtoxin-A (onaBoNT-A). METHODS: Female OAB patients refractory to OAB drugs were consented for this study. Cystoscopic-guided punch bladder biopsy was obtained at the time of injection of onaBoNT-A 100 units. The expression of 13 miR species, selected for their known effect on neurotrophin expression and smooth muscle function, was measured. PVRs and urine nerve growth factor (NGF) levels were measured at baseline and at the follow-up visit. RESULTS: Fourteen patients with mean age of 66 years were consented. Of these patients, nine maintained PVRs <200 mL after onaBoNT-A injection to comprise the low PVR group. The other five patients with PVRs ≥200 mL comprised the high PVR group. The expression of miR221 and miR125b was upregulated by 11- and 2-fold, respectively, in patients who responded with low PVRs after onaBoNT-A (P < 0.05). Urine NGF levels at baseline were not different between the two groups. CONCLUSIONS: This study suggests that deficiency in the pretreatment expression of miR221 and miR125b may predispose OAB patients to high PVRs following intradetrusor onaBoNT-A. Additional studies are needed to better understand the role of miRs in OAB.

Novel contrast mixture improves bladder wall contrast for visualizing bladder injury.

Here, we tested whether combined contrast-enhanced magnetic resonance imaging (CCE-MRI), using a mixture of gadolinium- and iron oxide-based contrast agents, can segment the bladder wall from the bladder lumen. CCE-MRI relies on the differences in particle size and contrast mechanisms of two agents for improved image contrast. Under isoflurane anesthesia, T1-weighted imaging of adult female Sprague-Dawley rat bladder was performed using standard turbospin echo sequences at 7 Tesla, before and after transurethral instillation of 0.3 ml of single-contrast MRI or CCE-MRI composed of 0.4-64 mM of gadolinium chelate (Gd-DTPA/Gadavist) and 5 mM ferumoxytol. Bladder wall contrast was assessed in the control group exposed to saline and in the bladder injury group exposed to 0.5 ml of protamine sulfate (10 mg/ml) for 30 min. CCE-MRI following instillation of 0.4-4 mM Gd-DTPA and 5 mM ferumoxytol mixture achieved segmentation between the bladder lumen and bladder wall. Hyperintensity in the bladder wall combined with hypointensity in the lumen is consistent with the increased diffusion of the dissolved Gd-DTPA and simultaneous localization of the larger nanoparticles of ferumoxytol in the lumen. The normalized hyperintense signal in the bladder wall increased from 0.46 ± 0.07 in control group to 0.73 ± 0.14 in the protamine sulfate-exposed group (P < 0.0001). CCE-MRI following instillation of contrast mixture identifies bladder wall changes likely associated with bladder injury with improved image contrast.