Background The large unmet need of hidradenitis suppurativa/acne inversa (HS) therapy requires the elucidation of disease‐driving mechanisms and tissue targeting. Objective Robust characterization of the underlying HS mechanisms and detection of the involved skin compartments. Methods Hidradenitis suppurativa/acne inversa molecular taxonomy and key signalling pathways were studied by whole transcriptome profiling. Dysregulated genes were detected by comparing lesional and non‐lesional skin obtained from female HS patients and matched healthy controls using the Agilent array platform. The differential gene expression was confirmed by quantitative real‐time PCR and targeted protein characterization via immunohistochemistry in another set of female patients. HS‐involved skin compartments were also recognized by immunohistochemistry. Results Alterations to key regulatory pathways involving glucocorticoid receptor, atherosclerosis, HIF1α and IL17A signalling as well as inhibition of matrix metalloproteases were detected. From a functional standpoint, cellular assembly, maintenance and movement, haematological system development and function, immune cell trafficking and antimicrobial response were key processes probably being affected in HS. Sixteen genes were found to characterize HS from a molecular standpoint (DEFB4, MMP1, GJB2, PI3, KRT16, MMP9, SERPINB4, SERPINB3, SPRR3, S100A8, S100A9, S100A12, S100A7A (15), KRT6A, TCN1, TMPRSS11D). Among the proteins strongly expressed in HS, calgranulin‐A, calgranulin‐B and serpin‐B4 were detected in the hair root sheath, koebnerisin and connexin‐32 in stratum granulosum, transcobalamin‐1 in stratum spinosum/hair root sheath, small prolin‐rich protein‐3 in apocrine sweat gland ducts/sebaceous glands‐ducts and matrix metallopeptidase‐9 in resident monocytes. Conclusion Our findings highlight a panel of immune‐related drivers in HS, which influence innate immunity and cell differentiation in follicular and epidermal keratinocytes as well as skin glands.

BackgroundApocrine glands have been long considered as the initial targeted skin compartment in hidradenitis suppurativa/acne inversa (HS).ObjectiveDetection of apocrine gland involvement in HS.MethodsApocrine glands were isolated from skin biopsies of involved and uninvolved skin of HS patients (n = 16, females : males 1 : 1) by laser capture microscopy and studied by whole transcriptome profiling. Dysregulated genes were detected by comparing lesional and non‐lesional skin obtained from female and male HS patients using the Agilent array platform.ResultsSULF1 was the only gene, whose expression levels were found upregulated in apocrine glands of HS lesions of the entire group. Further dysregulated genes associated with vascular functions (FGF1, IL17D and S100A9) were detected. Genes, which are characteristic for glandular epithelia, confirmed the glandular origin of the studied tissue. The gene upregulation profile of female apocrine glands included several genes (MRO, DYRK3, SDK2, GLB1L, CATSPERB and PRPS2), which are specifically transcribed during testis differentiation and/or regulated by androgens. Genes related to lipid metabolism (AGPAT3, GAL, ELOVL3, THRSP, DGAT2L3, OLAH, THRSP, FADS1, NR2F2, FADS2, PTGDS and HAO2) were mostly downregulated in the apocrine glands of male patients. The levels of RECK and PCSK5, which are upstream genes of metalloproteinase‐9 and ‐1, and of S100A9, which encodes calgranulin B, were commonly increased in the apocrine glands of female and male patients, respectively, and in our previous whole skin study.ConclusionOur findings indicate that apocrine glands are bystanders in HS. Inflammatory signalling is not prominent but a gender‐specific response was detected, which is mostly associated with androgen‐responsive genes in females and alterations of lipid metabolism in males.

Dynamical decoupling sequences detect spin system and solvent-induced decoherence contributions for nitroxides, trityl radicals and gadolinium complexes in glassy water–glycerol.

Chronic inflammation and dysregulated epithelial differentiation, especially of hair follicle keratinocytes, have been suggested as the major pathogenetic pathways of hidradenitis suppurativa/acne inversa (HS). On the other hand, obesity and metabolic syndrome have additionally been considered as an important risk factor. With adalimumab, a drug has already been approved and numerous other compounds are in advanced-stage clinical studies. A systematic review was conducted to detect and corroborate HS pathogenetic mechanisms at the molecular level and identify HS molecular markers. The obtained data were used to confirm studied and off-label administered drugs and to identify additional compounds for drug repurposing. A robust, strongly associated group of HS biomarkers was detected. The triad of HS pathogenesis, namely upregulated inflammation, altered epithelial differentiation and dysregulated metabolism/hormone signaling was confirmed, the molecular association of HS with certain comorbid disorders, such as inflammatory bowel disease, arthritis, type I diabetes mellitus and lipids/atherosclerosis/adipogenesis was verified and common biomarkers were identified. The molecular suitability of compounds in clinical studies was confirmed and 31 potential HS repurposing drugs, among them 10 drugs already launched for other disorders, were detected. This systematic review provides evidence for the importance of molecular studies to advance the knowledge regarding pathogenesis, future treatment and biomarker-supported clinical course follow-up in HS.

Despite the rapid development in hidradenitis suppurativa (HS) research, the immediate introduction of potent therapeutic compounds in clinical trials and the lack of definitive outcome measures have led to the discontinuation of potential therapeutic compound studies. HS is a solely human disease, and therefore, the search for preclinical human models has been given priority. The 3D-SeboSkin model, a co-culture of human skin explants with human SZ95 sebocytes as a feeder layer, has been shown to prevent the rapid degeneration of human skin in culture and has been validated for HS preclinical studies. In this work, the HS 3D-SeboSkin model has been employed to characterize cellular and molecular effects of the EMA- and FDA-approved biologic adalimumab. Adalimumab, a tumor necrosis factor-α inhibitor, was shown to target inflammatory cells present in HS lesions, inducing a prominent anti-inflammatory response and contributing to tissue regeneration through a wound healing mechanism. Adalimumab inhibited the lesional tissue expression of TNF-α, IL-3, IL-15, and MCP-3 and downregulated the secretion of IL-1α, IL-5, RANTES, MCP-2, TNF-α, TNF-β, TGF-β, and IFN-γ. In contrast, IL-6 was stimulated. The compound failed to modify abnormal epithelial cell differentiation present in the HS lesions. Patients with Hurley stage II lesions exhibited stronger expression of autophagy proteins in perilesional than in lesional skin. Adalimumab modified the levels of the pro-apoptotic proteins LC3A, LC3B, and p62 in an individual, patient-dependent manner. Finally, adalimumab did not modify the NFκB signal proteins in SZ95 sebocytes and NHK-19 keratinocytes, used to study this specific pathway. The administration of the validated HS 3D-SeboSkin model in ex vivo studies prior to clinical trials could elucidate the individual pathogenetic targets of therapeutic candidates and, therefore, increase the success rates of clinical studies, minimizing HS drug development costs.

In the analysis of polymers by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), a commonly observed ionization pathway is cation adduct formation, as polymers often lack easily ionizable (basic/acidic) functional groups. The mechanism of this process has been hypothesized to involve gas-phase cation attachment. In previous experiments, a split sample plate set up has been introduced, enabling separate deposition of the components on individual MALDI plates. The plates are divided by a small gap of a few micrometers, allowing simultaneous laser irradiation from both plates, while precluding the possibility of any other interactions prior to ablation. Here, we extend on these studies by using different polymer-salt combinations to test the generalizability of a gas phase ionization process. Clear evidence for in-plume ionization is presented for the model polymers poly(methyl methacrylate) and polystyrene. Furthermore, the contribution of in-plume processes to the overall ion formation by cationization is considered, providing a first estimate for the importance of this pathway.

The manuscript presents a dynamical decoupling study of three EPR spin labels in glassy water-glycerol, corresponding to common experimental conditions for dipolar spectroscopy. The main text and the supporting information (split into part A and B) are uploaded as separate PDF documents and contain all information for interpreting and reproducing the findings.<br>

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