Oxidative damage control in a human (mini-) organ: Nrf2 activation protects against oxidative stress-induced hair growth inhibition

The in situ control of redox insult in human organs is of major clinical relevance, yet remains incompletely understood. Activation of Nrf2, the “master regulator” of genes controlling cellular redox homeostasis, is advocated as a therapeutic strategy for diseases with severely impaired redox balance. It remains to be shown whether this strategy is effective in human organs, rather than isolated human cell types. We have therefore explored the role of Nrf2 in a uniquely accessible human (mini-) organ, human scalp hair follicles (HFs). Microarray and qPCR analysis of human HFs following Nrf2 activation using sulforaphane identified the modulation of phase II metabolism, ROS clearance, the pentose phosphate pathway and glutathione homeostasis. Nrf2 knockdown (siRNA) in cultured human HFs confirmed the regulation of key Nrf2 target genes (i.e. HO-1, NQO1, GSR, GCLC, ABCC1, PRDX1). Importantly, Nrf2 activation significantly reduced ROS levels and associated lipid peroxidation. Nrf2 pre-activation reduced oxidative stress-stimulated (H2O2 or menadione) premature catagen and hair growth inhibition, significantly ameliorated the H2O2-dependent increase in matrix keratinocyte apoptosis and reversed the ROS-induced reduction in proliferation. This study thus provides direct evidence for the crucial role of Nrf2 in protecting human organ function (i.e. scalp HFs) against redox insult

Mapping the expression of epithelial hair follicle stem cell-related transcription factors LHX2 and SOX9 in the human hair follicle

In the murine hair follicle (HF), the transcription factors LHX2 and SOX9 are implicated in epithelial hair follicle stem cell (eHFSC) self-renewal and the maintenance of eHFSC niche characteristics. However, the exact expression patterns of LHX2 and SOX9 in the human HF are unclear. Therefore, we have quantitatively mapped the localisation of known human eHFSC markers keratin 15 (K15) and keratin 19 (K19) in the outer root sheath (ORS) of male occipital scalp anagen HFs and related this to the localisation of LHX2 and SOX9 protein expression. As expected, K15(+) and K19(+) cells represented two distinct progenitor cell populations in the bulge and in the proximal bulb ORS (pbORS). Interestingly, cell fluorescence for K19 was significantly stronger within the pbORS versus the bulge, and vice versa for K15, describing a hitherto unrecognised differential expression pattern. LHX2 and SOX9 expressing cells were distributed throughout the ORS, including the bulge, but were not restricted to it. SOX9 expression was most prominent in the ORS immediately below the human bulge, whereas LHX2(+) cells were similarly distributed between the sub-bulge and pbORS, that is compartments not enriched with quiescent eHFSCs. During catagen development, the intensity of LHX2 and SOX9 protein expression increased in the proximal HF epithelium. Double immunostaining showed that the majority of SOX9(+) cells in the human anagen HF epithelium did not co-express K15, K19 or LHX2. This expression profile suggests that LHX2 and SOX9 highlight distinct epithelial progenitor cell populations, in addition to K15(+) or K19(+) cells, that could play an important role in the maintenance of the human HF epithelium

Dandruff lesional scalp skin exhibits epidermal T cell infiltration and a weakened hair follicle immune privilege

Dandruff is characterised by the presence of perivascular leukocytes and mild inflammation; however, the immune microenvironment of dandruff-affected scalp skin and the potential changes to the hair follicle's (HF) physiological immune privilege (HF IP) remain unknown. Here, we characterised the HF immune microenvironment and immune privilege status in dandruff-affected scalp skin. We assessed relevant key parameters in healthy versus dandruff-affected human scalp biopsies using quantitative immunohistomorphometry, laser capture microdissection, and RNA sequencing. The number of epidermal CD4 and CD8 T cells was increased in lesional dandruff scalp skin, while the number of MHC class II /CD1a Langerhans cells was decreased in the infundibulum. The number of intrafollicular and perifollicular CD4 T cells and CD8 T cells, perifollicular CD68 macrophages, and tryptase mast cells remained unchanged. Interestingly, MHC class Ia and ß2-microglobulin protein expression were significantly increased specifically in the suprabulbar outer root sheath (ORS) compartment of dandruff-associated HFs. RNAseq analysis of laser capture micro-dissected suprabulbar ORS compartment revealed antigen presentation pathway as the top regulated canonical pathway, along with the upregulation of HF-IP genes such as HLA-C, HLA-DP, and TAP1, which are normally down-regulated in healthy HFs. Intrafollicular protein expression of known HF IP guardians (CD200 and α-MSH) and 'danger signals' (MICA and CXCL10) remained unaltered at the IP sites of dandruff lesional HFs compared to non-lesional and healthy HFs. Instead, the expression of macrophage migration inhibiting factor (MIF), another HF IP guardian, was reduced. Together, this work shows that dandruff is associated with epidermal T-cell infiltration and a weakened HF IP in the suprabulbar ORS of HFs in dandruff lesional scalp

A Folliculocentric Perspective of Dandruff Pathogenesis:Could A Troublesome Condition Be Caused by Changes to a Natural Secretory Mechanism?

Dandruff is a common scalp condition, which frequently causes psychological distress in those affected. Dandruff is considered to be caused by an interplay of several factors. However, the pathogenesis of dandruff remains under-investigated, especially with respect to the contribution of the hair follicle. As the hair follicle exhibits unique immune-modulatory properties, including the creation of an immunoinhibitory, immune-privileged milieu, we propose a novel hypothesis taking into account the role of the hair follicle. We hypothesize that the changes and imbalance of yeast and bacterial species, along with increasing proinflammatory sebum by-products, leads to the activation of immune response and inflammation. Hair follicle keratinocytes may then detect these changes in scalp microbiota resulting in the recruitment of leukocytes to the inflammation site. These changes in the scalp skin immune-microenvironment may impact hair follicle immune privilege status, which opens new avenues into exploring the role of the hair follicle in dandruff pathogenesis. Also see the video abstract here: https://youtu.be/mEZEznCYtNs.</p

Differential Expression of Insulin-Like Growth Factor 1 and Wnt Family Member 4 Correlates With Functional Heterogeneity of Human Dermal Fibroblasts

Although human dermis contains distinct fibroblast subpopulations, the functional heterogeneity of fibroblast lines from different donors is under-appreciated. We identified one commercially sourced fibroblast line (c64a) that failed to express α-smooth muscle actin (α-SMA), a marker linked to fibroblast contractility, even when treated with transforming growth factor-β1 (TGF-β1). Gene expression profiling identified insulin-like growth factor 1 (IGF1) as being expressed more highly, and Asporin (ASPN) and Wnt family member 4 (WNT4) expressed at lower levels, in c64a fibroblasts compared to three fibroblast lines that had been generated in-house, independent of TGF-β1 treatment. TGF-β1 increased expression of C-X-C motif chemokine ligand 1 (CXCL1) in c64a cells to a greater extent than in the other lines. The c64a gene expression profile did not correspond to any dermal fibroblast subpopulation identified by single-cell RNAseq of freshly isolated human skin cells. In skin reconstitution assays, c64a fibroblasts did not support epidermal stratification as effectively as other lines tested. In fibroblast lines generated in-house, shRNA-mediated knockdown of IGF1 increased α-SMA expression without affecting epidermal stratification. Conversely, WNT4 knockdown had no consistent effect on α-SMA expression, but increased the ability of fibroblasts to support epidermal stratification. Thus, by comparing the properties of different lines of cultured dermal fibroblasts, we have identified IGF1 and WNT4 as candidate mediators of two distinct dermal functions: myofibroblast formation and epidermal maintenance

Clinical profile of COVID-19 patients and their length of stay: Tertiary care hospital experience

Background: SARSCoV-2, a coronavirus that causes COVID-19, is spreading rapidly. By the middle of August-2021, it has affected over 3 million confirmed cases in India. The main aim of this study was to examine the clinical profile of COVID-19 patients and their length of stay during treatment in a hospital. Materials and Methods: It was a hospital-based retrospective study conducted by using a total enumeration technique in July–August 2021 at Nehru Hospital, Postgraduate Institute of Medical Education and Research (PGIMER) in India. The present study was conducted on 72 COVID-19 patients who took treatment in 4C and 5C wards. Structured questionnaires were used to collect data, which included bio-demographic factors and questions about their treatment and length of stay. Results: The majority of the 72 COVID-19 positive patients were men (62%), belonged to the age group of 41–60 years (35%), had SpO2 levels ranging from 91%–95% (45%), and received room air O2 therapy (63%) during their treatment in the hospital. Female patients had a longer length of stay (7.33 days), patients under the age of 20 years had the longest hospital stay (11.5 days), patients with SpO2 less than 70% had the longest hospital stay (8 days), and patients who received oxygen using a non-rebreathing mask had the longest hospital stay (11 days). Conclusion: To avoid panic situations, regular admission and discharge of patients was essential due to the considerable increase in cases during the second wave. Patient length of stay was reduced as a consequence of collaboration and cooperation among all physicians, residents, staff nurses, and paramedics, with the goal of discharging the patient after a room air trial and follow up if needed