A trivalent nucleosome interaction by PHIP/BRWD2 is disrupted in neurodevelopmental disorders and cancer.

Mutations in the PHIP/BRWD2 chromatin regulator cause the human neurodevelopmental disorder Chung-Jansen syndrome, while alterations in PHIP expression are linked to cancer. Precisely how PHIP functions in these contexts is not fully understood. Here we demonstrate that PHIP is a chromatin-associated CRL4 ubiquitin ligase substrate receptor and is required for CRL4 recruitment to chromatin. PHIP binds to chromatin through a trivalent reader domain consisting of a H3K4-methyl binding Tudor domain and two bromodomains (BD1 and BD2). Using semisynthetic nucleosomes with defined histone post-translational modifications, we characterize PHIPs BD1 and BD2 as respective readers of H3K14ac and H4K12ac, and identify human disease-associated mutations in each domain and the intervening linker region that likely disrupt chromatin binding. These findings provide new insight into the biological function of this enigmatic chromatin protein and set the stage for the identification of both upstream chromatin modifiers and downstream targets of PHIP in human disease.

The impact of irritant challenge on the skin barrier and myeloid-resident immune cells in women who are postmenopausal is modulated by hormone replacement therapy.

BACKGROUND: Sex hormone changes during menopausal transition contribute to declining skin health. However, how menopause and its treatment by hormone replacement therapy (HRT) impact the skin barrier and immune system is unclear. OBJECTIVES: To examine how menopause and HRT affect the skin barrier and immune cell composition in postmenopausal women following irritant challenge. METHODS: Two cohorts of postmenopausal women were recruited to the study. The first cohort consisted of 10 untreated women [HRT-; mean (SEM) age 56.5 (1.6) years (range 48-63)] and the second was composed of 8 women receiving HRT [HRT+; mean (SEM) age 54.0 (2.1) years (range 48-63)]. Skin irritation was induced by applying topical sodium lauryl sulfate (SLS) 1.25% to occluded buttock skin for 48 h. Clinical assessment was conducted after 24 h, followed by biopsy of both SLS-challenged and unchallenged skin for analysis of skin barrier proteins and immune cell distribution using immunofluorescence. RESULTS: Clinically, there were no significant differences in skin irritant responses between those taking or not taking HRT (including increased skin redness and blood flow). In response to SLS challenge a significant increase in transepidermal water loss (P < 0.05), filaggrin deposition and cytokeratin 10 (K10)+ cell layers (P < 0.01) was observed in individuals receiving HRT compared with the HRT- group. Following SLS challenge in individuals taking HRT, a significant (P < 0.01) reduction in CD207+ cells in the epidermis was observed, accompanied by an increase of CD207+ cells in the dermis, indicative of migrating Langerhans cells (LCs). Significantly fewer migrating LCs were found in those who were not receiving HRT (P < 0.01). Furthermore, the numbers of dermal dendritic cells (DCs), macrophages, and CD11c+CD206- and CD68+CD206- subsets were found to be significantly (P < 0.05) higher in those taking HRT following SLS challenge. CONCLUSIONS: Individuals receiving HRT displayed enhanced skin barrier response to SLS challenge with thicker filaggrin and increased K10+ epidermal cell layers. Following challenge, HRT users exhibited elevated LC, inflammatory DC and macrophage counts in the dermis. These may render skin both more prone to inflammation and more capable of resolving it, while also promoting skin repair.

Changes to a person's sex hormones during the menopause can affect the skin. The effects of the menopause on the immune system and the skin are still unclear. The effects of a treatment called 'hormone replacement therapy' ('HRT') are also still unclear. We investigated the effects of HRT on immune cells and skin barrier function in women who had been through the menopause. To do this, we compared the skin of two groups of women: those who were taking HRT and those who were not. Looking at skin redness and blood flow, we found that the two groups of women had a similar response to their skin being irritated by a chemical called 'SLS'. Yet, the women taking HRT had increased water loss from their skin after SLS was applied. We also found that after having SLS applied, women on HRT had a thicker layer of cells in the top section of their skin that produced more of a protein that helps protect the skin. Women taking HRT also had more inflammatory cells in the deeper layers of their skin after SLS was applied. Overall, our findings suggest that HRT may improve the skin's immune response to irritating substances. HRT could have an effect on the skin's ability to repair itself and on general skin health.

Prediction, screening and characterization of novel bioactive tetrapeptide matrikines for skin rejuvenation.

BACKGROUND: Extracellular matrices play a critical role in tissue structure and function and aberrant remodelling of these matrices is a hallmark of many age-related diseases. In skin, loss of dermal collagens and disorganization of elastic fibre components are key features of photoageing. Although the application of some small matrix-derived peptides to aged skin has been shown to beneficially affect in vitro cell behaviour and, in vivo, molecular architecture and clinical appearance, the discovery of new peptides has lacked a guiding hypothesis. OBJECTIVES: To identify, using protease cleavage site prediction, novel putative matrikines with beneficial activities for skin composition and structure. METHODS: Here, we present an in silico (peptide cleavage prediction) to in vitro (proteomic and transcriptomic activity testing in cultured human dermal fibroblasts) to in vivo (short-term patch test and longer-term split-face clinical study) discovery pipeline, which enables the identification and characterization of peptides with differential activities. RESULTS: Using this pipeline we showed that cultured fibroblasts were responsive to all applied peptides, but their associated bioactivity was sequence-dependent. Based on bioactivity, toxicity and protein source, we further characterized a combination of two novel peptides, GPKG (glycine-proline-lysine-glycine) and LSVD (leucine-serine-valine-aspartate), that acted in vitro to enhance the transcription of matrix -organization and cell proliferation genes and in vivo (in a short-term patch test) to promote processes associated with epithelial and dermal maintenance and remodelling. Prolonged use of a formulation containing these peptides in a split-face clinical study led to significantly improved measures of crow's feet and firmness in a mixed population. CONCLUSIONS: This approach to peptide discovery and testing can identify new synthetic matrikines, providing insights into biological mechanisms of tissue homeostasis and repair and new pathways to clinical intervention.

Like other organs and tissues, the skin is composed of both cells and a complex network of molecules and proteins called an extracellular matrix. This matrix contains proteins such as collagen and elastin and undergoes many changes when the skin is damaged by the sun. We know from previous studies that small parts of matrix proteins (called peptide 'matrikines') can help to treat the signs of sun-related skin ageing. In this UK study, we show that new beneficial peptides (with matrikine activity) can be identified using machine learning (artificial intelligence) techniques that predict where common matrix proteins might be 'cut' by skin enzymes. Candidate peptides were first made in the laboratory and then applied to skin cells in culture. These cell culture screens demonstrated that, while all the peptides showed some matrikine activity, two were particularly promising. These two peptides were then tested in a short-term study on the forearm skin of volunteers and, in a longer-term study, on the face. We found that the combination of these two peptides can prompt forearm skin cells to express genes that are involved in many different aspect of skin health and, over the longer 6-month period, produce visible benefits in the appearance of fine lines and wrinkles and firmness on the face. Our findings suggest that this approach may be able to identify beneficial peptide treatments for not only skin ageing and diseases, but also unwanted changes in the extracellular matrix of other tissues and organs.

Cosmetic retinoid use in photoaged skin: A review of the compounds, their use and mechanisms of action.

The inevitable attrition of skin due to ultraviolet radiation, termed photoaging, can be partially restored by treatment with retinoid compounds. Photoaged skin in lightly pigmented individuals, clinically presents with the appearance of wrinkles, increased laxity, and hyper- and hypopigmentation. Underlying these visible signs of ageing are histological features such as epidermal thinning, dermal-epidermal junction flattening, solar elastosis and loss of the dermal fibrillin microfibrillar network, fibrillar collagen and glycosaminoglycans. Retinoid compounds are comprised of three main generations with the first generation (all-trans retinoic acid, retinol, retinaldehyde and retinyl esters) primarily used for the clinical and cosmetic treatment of photoaging, with varying degrees of efficacy, tolerance and stability. All-trans retinoic acid is considered the 'gold standard' for skin rejuvenation; however, it is a prescription-only product largely confined to clinical use. Therefore, retinoid derivatives are readily incorporated into cosmeceutical formulations. The literature reported in this review suggests that retinol, retinyl esters and retinaldehyde that are used in many cosmeceutical products, are efficacious, safe and well-tolerated. Once in the skin, retinoids utilize a complex signalling pathway that promotes remodelling of photoaged epidermis and dermis and leads to the improvement of the cutaneous signs of photoaging.

L'altération inévitable de la peau due aux rayons ultraviolets, appelée photovieillissement, peut être partiellement restaurée par un traitement à base de composés rétinoïdes. Chez les personnes à la pigmentation claire, le photovieillissement de la peau se manifeste au plan clinique par l'apparition de rides, un relâchement accru et une hyperpigmentation ou hypopigmentation. Ces signes visibles du vieillissement sont sous­tendus par des caractéristiques histologiques telles que l'amincissement de l'épiderme, l'aplatissement de la jonction dermo­épidermique, l'élastose solaire et la perte du réseau microfibrillaire de fibrilline dermique, du collagène fibrillaire et des glycosaminoglycanes. Les composés rétinoïdes sont constitués de trois générations principales, la première génération (acide tout­trans rétinoïque, rétinol, rétinaldéhyde et esters de rétinyle) étant principalement utilisée pour le traitement clinique et cosmétique du photovieillissement, avec des degrés variables d'efficacité, de tolérance et de stabilité. L'acide tout­trans rétinoïque est considéré comme la référence en matière de rajeunissement de la peau; il s'agit toutefois d'un produit délivré uniquement sur ordonnance, dont l'utilisation est largement limitée au domaine clinique. Les dérivés rétinoïdes sont donc volontiers incorporés ds formulations cosméceutiques. La littérature citée dans cette synthèse bibliographique laisse penser que le rétinol, les esters de rétinyle et le rétinaldéhyde, utilisés dans de nombreux produits cosmétiques, sont efficaces, sûrs et bien tolérés. Une fois dans la peau, les rétinoïdes utilisent une voie de signalisation complexe qui favorise le remodelage de l'épiderme et du derme photovieillis, et conduit à l'amélioration des signes cutanés du photovieillissement.

Skin ageing and topical rejuvenation strategies.

Skin ageing is a complex process involving the additive effects of skin's interaction with its external environment, predominantly chronic sun exposure, upon a background of time-dependent intrinsic ageing. Skin health and beauty is considered one of the principal factors perceived to represent overall 'health and wellbeing'; thus, the demand for skin rejuvenation strategies has rapidly increased, with a worldwide annual expenditure expected to grow from $US24.6 billion to around $US44.5 billion by 2030 (https://www.databridgemarketresearch.com/reports/global-facial-rejuvenation-market). Skin rejuvenation can be achieved in several ways, ranging from laser and device-based treatments to chemical peels and injectables; however, topical skin care regimes are a mainstay treatment for ageing skin and all patients seeking skin rejuvenation can benefit from this relatively low-risk intervention. While the most efficacious topical rejuvenation treatment is application of tretinoin (all-trans retinoic acid) - a prescription-only medicine considered to be the clinical 'gold standard' - a hybrid category of 'cosmeceutical' products at the midpoint of the spectrum of cosmetics and pharmaceutical has emerged. This article reviews the clinical manifestations of skin ageing and the available topical treatments for skin rejuvenation, including retinoids, peptides and antioxidants.

How growers make decisions impacts plant disease control.

While the spread of plant disease depends strongly on biological factors driving transmission, it also has a human dimension. Disease control depends on decisions made by individual growers, who are in turn influenced by a broad range of factors. Despite this, human behaviour has rarely been included in plant epidemic models. Considering Cassava Brown Streak Disease, we model how the perceived increase in profit due to disease management influences participation in clean seed systems (CSS). Our models are rooted in game theory, with growers making strategic decisions based on the expected profitability of different control strategies. We find that both the information used by growers to assess profitability and the perception of economic and epidemiological parameters influence long-term participation in the CSS. Over-estimation of infection risk leads to lower participation in the CSS, as growers perceive that paying for the CSS will be futile. Additionally, even though good disease management can be achieved through the implementation of CSS, and a scenario where all controllers use the CSS is achievable when growers base their decision on the average of their entire strategy, CBSD is rarely eliminated from the system. These results are robust to stochastic and spatial effects. Our work highlights the importance of including human behaviour in plant disease models, but also the significance of how that behaviour is included.

A Specific CNOT1 Mutation Results in a Novel Syndrome of Pancreatic Agenesis and Holoprosencephaly through Impaired Pancreatic and Neurological Development.

We report a recurrent CNOT1 de novo missense mutation, GenBank: NM_016284.4; c.1603C>T (p.Arg535Cys), resulting in a syndrome of pancreatic agenesis and abnormal forebrain development in three individuals and a similar phenotype in mice. CNOT1 is a transcriptional repressor that has been suggested as being critical for maintaining embryonic stem cells in a pluripotent state. These findings suggest that CNOT1 plays a critical role in pancreatic and neurological development and describe a novel genetic syndrome of pancreatic agenesis and holoprosencephaly.

Wound fluid sampling methods for proteomic studies: A scoping review.

Understanding why some wounds are hard to heal is important for improving care and developing more effective treatments. The method of sample collection used is an integral step in the research process and thus may affect the results obtained. The primary objective of this study was to summarise and map the methods currently used to sample wound fluid for protein profiling and analysis. Eligible studies were those that used a sampling method to collect wound fluid from any human wound for analysis of proteins. A search for eligible studies was performed using MEDLINE, Embase and CINAHL Plus in May 2020. All references were screened for eligibility by one reviewer, followed by discussion and consensus with a second reviewer. Quantitative data were mapped and visualised using appropriate software and summarised via a narrative summary. After screening, 280 studies were included in this review. The most commonly used group of wound fluid collection methods were vacuum, drainage or use of other external devices, with surgical wounds being the most common sample source. Other frequently used collection methods were extraction from absorbent materials, collection beneath an occlusive dressing and direct collection of wound fluid. This scoping review highlights the variety of methods used for wound fluid collection. Many studies had small sample sizes and short sample collection periods; these weaknesses have hampered the discovery and validation of novel biomarkers. Future research should aim to assess the reproducibility and feasibility of sampling and analytical methods for use in larger longitudinal studies.

Ultraviolet radiation-induced degradation of dermal extracellular matrix and protection by green tea catechins: a randomized controlled trial.

BACKGROUND: Loss and remodelling of the dermal extracellular matrix (ECM) are key features of photodamaged human skin. Green tea catechins (GTCs) have been explored for their anti-inflammatory and chemopreventive properties, but data on the impact of GTCs on ultraviolet radiation (UVR)-induced changes to the dermal ECM are lacking. AIM: To investigate the effect of an inflammatory dose of solar-simulated UVR on human dermal ECM and potential for protection by GTCs in a double-blind randomized controlled trial. METHODS: In total, 50 healthy white (Fitzpatrick skin type I-II) adults aged 18-65 years were randomized to a combination of GTCs 540 mg plus vitamin C 50 mg or to placebo twice daily for 12 weeks. The impact of solar-simulated UVR at 3 × minimal erythema dose on the dermal collagen and elastic fibre networks was assessed by histology and immunohistochemistry in all participants at baseline. The impact of GTC supplementation on UVR-induced effects was compared between the groups post-supplementation. RESULTS: The area of papillary dermis covered by collagen and elastic fibres was significantly lower (P < 0.001) in UVR-exposed skin than in unexposed skin. Significantly lower levels of fibrillin-rich microfibrils (P = 0.02), fibulin-2 (P < 0.001) and fibulin-5 (P < 0.001) were seen in UVR-exposed than unexposed skin, while procollagen-1 deposition was significantly higher in UVR-exposed skin (P = 0.01). Following GTC supplementation, the UVR-induced change in fibulin-5 was abrogated in the active group but not the placebo group, with no difference between the two groups for other components. CONCLUSIONS: Acute UVR induced significant changes in the human dermal collagen and elastic fibre networks, whereas oral GTCs conferred specific UVR protection to fibulin-5. Future studies could explore the impact of GTCs on the effects of repeated suberythemal UVR exposure of human skin.

Multifaceted amelioration of cutaneous photoageing by (0.3%) retinol.

BACKGROUND: Although retinol skin care products improve the appearance of photoaged skin, there is a need for an effective retinol concentration that provides skin benefits without irritation. OBJECTIVE: To compare the efficacy of topical 0.1%, 0.3% and 1% retinol in remodelling the cutaneous architecture in an in vivo experimental patch test study, and to determine tolerance of the most effective formulations when used in a daily in-use escalation study. METHODS: For the patch test study, retinol products were applied under occlusion, to the extensor forearm of photoaged volunteers (n = 5; age range 66-84 years), and 3 mm skin biopsies obtained after 12 days. Effects of different retinol concentrations, and a vehicle control, on key epidermal and dermal biomarkers of cellular proliferation and dermal remodelling were compared to untreated baseline. Separately, participants (n = 218) recorded their tolerance to 0.3% or 1% retinol over a six-week, approved regimen, which gradually increased the facial applications to once nightly. RESULTS: Retinol treatment induced a stepwise increase in epidermal thickness and induced the expression of stratum corneum proteins, filaggrin and KPRP. 0.3% retinol and 1% retinol were comparably effective at inducing keratinocyte proliferation in the epidermis, whilst reducing e-cadherin expression. Fibrillin-rich microfibril deposition was increased following treatment with 0.3% and 1% retinol (p < 0.01); other dermal components remained unaltered (e.g., fibronectin, collagen fibrils, elastin), and no evidence of local inflammation was detected. The in-use study found that 0.3% retinol was better tolerated than 1% retinol, with fewer and milder adverse events reported (χ2 (1) = 23.97; p < 0.001). CONCLUSIONS: This study suggests that 1% and 0.3% retinol concentrations were similarly effective at remodelling photodamaged skin in an in vivo model of long-term use. Use of 0.3% retinol in the escalation study was associated with fewer adverse reactions when applied daily. Hence, 0.3% retinol may be better tolerated than 1% retinol, thereby allowing longer-term topical application.

CONTEXTE: Même si les produits de soins pour la peau à base de rétinol améliorent l'apparence de la peau photovieillie, il est nécessaire d'obtenir une concentration efficace de rétinol procurant des bénéfices cutanés sans irritation. OBJECTIF: Comparer l'efficacité du rétinol à 0.1%, 0.3% et 1% en application locale dans le remodelage de l'architecture cutanée dans une étude d'irritation cutanée in vivo expérimental, et déterminer la tolérance des formulations les plus efficaces lorsqu'elles sont utilisées dans une étude à doses progressives quotidiennes en cours d'utilisation. MÉTHODES: Pour l'étude d'irritation cutanée, des produits à base de rétinol ont été appliqués sous occlusion, sur le muscle extenseur de l'avant-bras de volontaires présentant des signes de photovieillissement (n = 5; tranche d'âge: 66 à 84 ans), et des biopsies cutanées de 3 mm ont été obtenues après 12 jours. Les effets des différentes concentrations de rétinol, et d'un véhicule témoin sur les principaux biomarqueurs épidermiques et dermiques de la prolifération cellulaire et du remodelage dermique ont été comparés à ceux observés à une région non traitée. Séparément, les participants (n = 218) ont enregistré leur tolérance au rétinol à 0.3% ou 1% au cours d'un schéma posologique approuvé de six semaines, qui a progressivement augmenté les applications faciales à une fois par nuit. RÉSULTATS: Le traitement par rétinol a induit une augmentation progressive de l'épaisseur épidermique, et a induit l'expression des protéines de la couche cornée, la filaggrine et le KPRP. Le rétinol à 0.3% et le rétinol à 1% étaient aussi efficaces pour induire la prolifération des kératinocytes dans l'épiderme, tout en réduisant l'expression de la cadhérine E. Le dépôt de microfibrilles riches en fibrilline a augmenté après un traitement par rétinol à 0.3% et 1% (p < 0.001). CONCLUSIONS: Cette étude suggère que les concentrations de rétinol de 1% et 0.3% étaient aussi efficaces pour remodeler la peau photolésée dans un modèle in vivo lors d'une utilisation à long terme. L'utilisation de rétinol à 0.3% dans l'étude à doses progressives a été associée à moins d'effets indésirables lorsqu'il est appliqué quotidiennement. Par conséquent, le rétinol à 0.3% peut être mieux toléré que le rétinol à 1%, permettant ainsi une application topique à plus long terme.

Examination of the Effectiveness of Direct Oral Anticoagulants in Comparison to Warfarin in an Obese Population.

Background: While commonly prescribed today, direct oral anticoagulants (DOACs) have historically been avoided in patients with class III obesity or a weight >120 kg due to limited literature regarding the efficacy and safety in this population. Objective: The overall objective was to examine the effectiveness of DOACs compared to warfarin in a population with obesity. Methods: Patients with a diagnosis of venous thromboembolism (VTE) or atrial fibrillation and a body mass index (BMI) ≥35 kg/m2 from August 1, 2015, to August 1, 2020, were included in this retrospective cohort study. Patients receiving a DOAC were matched in a 1:2 ratio to warfarin. The primary outcome was a composite of stroke or recurrent VTE. Secondary outcomes included the individual components of the primary outcome, hospitalization for bleed, and the primary outcome in patients with a BMI ≥40 kg/m2. Results: A total of 162 patients were included, with 54 and 108 in the DOAC and warfarin groups, respectively. Baseline BMI was similar between groups (45.7 kg/m2 for DOACs vs 43.8 kg/m2 for warfarin), with approximately 70% of patients having a BMI ≥40 kg/m2. The primary outcome occurred in 1 patient (1.9%) in the DOAC group and 2 patients (1.9%) in the warfarin group. The DOAC group had a higher, nonsignificant incidence of bleeding (5.6% vs 0.9%, P = 0.11). There was no difference between groups in incidence of deep vein thrombosis (DVT), pulmonary embolism (PE), or stroke in patients with a BMI ≥40 kg/m2. Conclusion: DOACs may be as efficacious as warfarin in the prevention of stroke or recurrent VTE in patients with a BMI of ≥35 kg/m2. Prospective, randomized trials are warranted to further assess the efficacy and safety of DOACs in this population.

A pseudomolecule-scale genome assembly of the liverwort Marchantia polymorpha.

Marchantia polymorpha has recently become a prime model for cellular, evo-devo, synthetic biological, and evolutionary investigations. We present a pseudomolecule-scale assembly of the M. polymorpha genome, making comparative genome structure analysis and classical genetic mapping approaches feasible. We anchored 88% of the M. polymorpha draft genome to a high-density linkage map resulting in eight pseudomolecules. We found that the overall genome structure of M. polymorpha is in some respects different from that of the model moss Physcomitrella patens. Specifically, genome collinearity between the two bryophyte genomes and vascular plants is limited, suggesting extensive rearrangements since divergence. Furthermore, recombination rates are greatest in the middle of the chromosome arms in M. polymorpha like in most vascular plant genomes, which is in contrast with P. patens where recombination rates are evenly distributed along the chromosomes. Nevertheless, some other properties of the genome are shared with P. patens. As in P. patens, DNA methylation in M. polymorpha is spread evenly along the chromosomes, which is in stark contrast with the angiosperm model Arabidopsis thaliana, where DNA methylation is strongly enriched at the centromeres. Nevertheless, DNA methylation and recombination rate are anticorrelated in all three species. Finally, M. polymorpha and P. patens centromeres are of similar structure and marked by high abundance of retroelements unlike in vascular plants. Taken together, the highly contiguous genome assembly we present opens unexplored avenues for M. polymorpha research by linking the physical and genetic maps, making novel genomic and genetic analyses, including map-based cloning, feasible.

Separation and Characterization of Endogenous Nucleosomes by Native Capillary Zone Electrophoresis-Top-Down Mass Spectrometry.

We report a novel platform [native capillary zone electrophoresis-top-down mass spectrometry (nCZE-TDMS)] for the separation and characterization of whole nucleosomes, their histone subunits, and post-translational modifications (PTMs). As the repeating unit of chromatin, mononucleosomes (Nucs) are an ∼200 kDa complex of DNA and histone proteins involved in the regulation of key cellular processes central to human health and disease. Unraveling the covalent modification landscape of histones and their defined stoichiometries within Nucs helps to explain epigenetic regulatory mechanisms. In nCZE-TDMS, online Nuc separation is followed by a three-tier tandem MS approach that measures the intact mass of Nucs, ejects and detects the constituent histones, and fragments to sequence the histone. The new platform was optimized with synthetic Nucs to significantly reduce both sample requirements and cost compared to direct infusion. Limits of detection were in the low-attomole range, with linearity of over ∼3 orders of magnitude. The nCZE-TDMS platform was applied to endogenous Nucs from two cell lines distinguished by overexpression or knockout of histone methyltransferase NSD2/MMSET, where analysis of constituent histones revealed changes in histone abundances over the course of the CZE separation. We are confident the nCZE-TDMS platform will help advance nucleosome-level research in the fields of chromatin and epigenetics.

Systemic sclerosis skin is a primed microenvironment for soft tissue calcification-a hypothesis.

Calcinosis cutis, defined as sub-epidermal deposition of calcium salts, is a major clinical problem in patients with SSc, affecting 20-40% of patients. A number of recognized factors associated with calcinosis have been identified, including disease duration, digital ischaemia and acro-osteolysis. Yet, to date, the pathogenesis of SSc-related calcinosis remains unknown, and currently there is no effective disease-modifying pharmacotherapy. Following onset of SSc, there are marked changes in the extracellular matrix (ECM) of the skin, notably a breakdown in the microfibrillar network and accumulation of type I collagen. Our hypothesis is that these pathological changes reflect a changing cellular phenotype and result in a primed microenvironment for soft tissue calcification, with SSc fibroblasts adopting a pro-osteogenic profile, and specific driving forces promoting tissue mineralization. Considering the role of the ECM in disease progression may help elucidate the mechanism(s) behind SSc-related calcinosis and inform the development of future therapeutic interventions.

The role of stem cells in uterine involution.

Uterine remodeling during pregnancy and repair postpartum are fundamental to the successful propagation of eutherian species. The most drastic remodeling occurs in species with invasively implanting embryos, including humans and mice. During embryo implantation, embryonic trophoblasts breach the epithelium, penetrating into the stroma. Stromal cell decidualization, which is critical for the establishment and maintenance of early pregnancy, occurs throughout the implantation site. Trophoblasts further invade into and remodel uterine spiral arteries, which is necessary for placental formation. The uterus increases in size up to 24-fold, which is largely attributed to myometrial expansion. Uterine changes that occur during pregnancy must then be resolved postpartum. Following parturition, the uterus repairs the remodeled tissue in the process of uterine involution. During involution, the majority of the endometrium is regenerated to replace the tissue that is shed postpartum. The myometrium returns to the pre-gravid state which is thought to occur through apoptosis and autophagy of smooth muscle cells. Although we understand the general process of postpartum uterine involution, the detailed mechanisms, particularly the role of putative stem cells, are poorly understood. This review discusses the evidence for the existence of epithelial, stromal and myometrial stem cells and their role in uterine involution. Gaps in knowledge and areas for future research are also considered. Studies of both postpartum and menstrual uterine repair, which likely involve similar mechanisms, are described under the broad definition of uterine involution. Although the primary focus of this review is human, mouse models are discussed to provide additional information.

The systemic influence of chronic smoking on skin structure and mechanical function.

One of the major functions of human skin is to provide protection from the environment. Although we cannot entirely avoid, for example, sun exposure, it is likely that exposure to other environmental factors could affect cutaneous function. A number of studies have identified smoking as one such factor that leads to both facial wrinkle formation and a decline in skin function. In addition to the direct physical effects of tobacco smoke on skin, its inhalation has additional profound systemic effects for the smoker. The adverse effects on the respiratory and cardiovascular systems from smoking are well known. Central to the pathological changes associated with smoking is the elastic fibre, a key component of the extracellular matrices of lungs. In this study we examined the systemic effect of chronic smoking (>40 cigarettes/day; >5 years) on the histology of the cutaneous elastic fibre system, the nanostructure and mechanics of one of its key components, the fibrillin-rich microfibril, and the micromechanical stiffness of the dermis and epidermis. We show that photoprotected skin of chronic smokers exhibits significant remodelling of the elastic fibre network (both elastin and fibrillin-rich microfibrils) as compared to the skin of age- and sex-matched non-smokers. This remodelling is not associated with increased gelatinase activity (as identified by in situ zymography). Histological remodelling is accompanied by significant ultrastructural changes to extracted fibrillin-rich microfibrils. Finally, using scanning acoustic microscopy, we demonstrated that chronic smoking significantly increases the stiffness of both the dermis and the epidermis. Taken together, these data suggest an unappreciated systemic effect of chronic inhalation of tobacco smoke on the cutaneous elastic fibre network. Such changes may in part underlie the skin wrinkling and loss of skin elasticity associated with smoking. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Evaluation of the safety and tolerability of spironolactone in patients with heart failure and chronic kidney disease.

BACKGROUND: Spironolactone reduces morbidity and mortality in patients with heart failure (HF) with reduced ejection fraction (EF) and decreases hospitalizations in HF with preserved EF. To minimize the risk of hyperkalemia, patients must have an estimated glomerular filtration rate (eGFR) > 30 mL/min/1.73 m2 and potassium < 5.0 mEq/L prior to initiation; however, spironolactone is prescribed outside these parameters. The objective of this study was to evaluate the safety and tolerability of spironolactone in patients with HF and chronic kidney disease (CKD). METHODS: This single-center, retrospective cohort study evaluated patients ≥ 18 years with HF and CKD stages 3-5 who received ≥ 48 h of spironolactone therapy and were hospitalized from February 2018 to August 2019. The primary outcome was incidence of hyperkalemia (potassium ≥ 5.5 mEq/L). RESULTS: Overall, 121 patients were evaluated: 52.1% (n = 63) had an EF > 40% and 47.9% (n = 58) had an EF ≤ 40% with 69.4% (n = 84) CKD stage 3, 24.8% (n = 30) stage 4, and 5.8% (n = 7) stage 5. Spironolactone was initiated prior to admission (PTA) for 54.5% (n = 66) of patients, while 45.5% (n = 55) of orders were initiated during hospitalization. Eight patients (6.6%) experienced inpatient hyperkalemia-all with PTA spironolactone. Patients who experienced inpatient hyperkalemia had a numerically lower eGFR that was not statistically significant (35.40 vs. 38.22 mL/min/1.73 m2; p = 0.730). Patients with CKD stage 3 (n = 4) had numerically higher rates of inpatient hyperkalemia than stages 4 (n = 1) or 5 (n = 3) (50%, 12.5%, and 37.5% respectively; p < 0.05). CONCLUSION: Spironolactone may be safe to initiate in hospitalized patients with HF and CKD; however, appropriateness of therapy must be assessed upon admission to the hospital. Larger studies are needed for conclusive results.

Daily photoprotection to prevent photoaging.

BACKGROUND: Extrinsic skin aging or photoaging was previously thought to be almost exclusively due to solar ultraviolet (UV) radiation. However, recent literature has described other contributing factors and clarification is thus required as to what extent and what type of daily photoprotection is needed to mitigate extrinsic skin aging. METHODS: We reviewed the existing scientific evidence on daily photoprotection, and specific requirements at the product level, to prevent extrinsic skin aging. We critically reviewed the existing evidence on potential ecological and toxicological risks which might be associated with daily photoprotection. RESULTS: Evidence shows that broad protection against the entire solar range of UVB, UVA, UVA1, visible light, and short infrared (IRA) is required to prevent extrinsic aging. Other exposome factors, such as air pollution and smoking, also contribute to skin aging. Daily broad-spectrum sunscreen photoprotection should thus contain antioxidant ingredients for additional benefits against UV, IRA, and pollution-induced oxidative stress as well as anti-aging active ingredients to provide clinical benefits against skin aging signs, such as wrinkles and dark spots. Broad-spectrum sunscreen containing pigments, such as iron oxide, may be required for melasma prevention. There is no conclusive clinical evidence that daily sunscreen use is unsafe or that it compromises vitamin D synthesis. CONCLUSION: Daily use of broad-spectrum sunscreen containing antioxidant and anti-aging active ingredients can effectively reduce extrinsic aging.

Predicting Proteolysis in Complex Proteomes Using Deep Learning.

Both protease- and reactive oxygen species (ROS)-mediated proteolysis are thought to be key effectors of tissue remodeling. We have previously shown that comparison of amino acid composition can predict the differential susceptibilities of proteins to photo-oxidation. However, predicting protein susceptibility to endogenous proteases remains challenging. Here, we aim to develop bioinformatics tools to (i) predict cleavage site locations (and hence putative protein susceptibilities) and (ii) compare the predicted vulnerabilities of skin proteins to protease- and ROS-mediated proteolysis. The first goal of this study was to experimentally evaluate the ability of existing protease cleavage site prediction models (PROSPER and DeepCleave) to identify experimentally determined MMP9 cleavage sites in two purified proteins and in a complex human dermal fibroblast-derived extracellular matrix (ECM) proteome. We subsequently developed deep bidirectional recurrent neural network (BRNN) models to predict cleavage sites for 14 tissue proteases. The predictions of the new models were tested against experimental datasets and combined with amino acid composition analysis (to predict ultraviolet radiation (UVR)/ROS susceptibility) in a new web app: the Manchester proteome susceptibility calculator (MPSC). The BRNN models performed better in predicting cleavage sites in native dermal ECM proteins than existing models (DeepCleave and PROSPER), and application of MPSC to the skin proteome suggests that: compared with the elastic fiber network, fibrillar collagens may be susceptible primarily to protease-mediated proteolysis. We also identify additional putative targets of oxidative damage (dermatopontin, fibulins and defensins) and protease action (laminins and nidogen). MPSC has the potential to identify potential targets of proteolysis in disparate tissues and disease states.

Heterogeneity of fibrillin-rich microfibrils extracted from human skin of diverse ethnicity.

The dermal elastic fibre network is the primary effector of skin elasticity, enabling it to extend and recoil many times over the lifetime of the individual. Fibrillin-rich microfibrils (FRMs) constitute integral components of the elastic fibre network, with their distribution showing differential deposition in the papillary dermis across individuals of diverse skin ethnicity. Despite these differential findings in histological presentation, it is not known if skin ethnicity influences FRM ultrastructure. FRMs are evolutionarily highly conserved from jellyfish to man and, regardless of tissue type or species, isolated FRMs have a characteristic 'beads-on-a-string' ultrastructural appearance, with an average inter-bead distance (or periodicity) of 56 nm. Here, skin biopsies were obtained from the photoprotected buttock of healthy volunteers (18-27 years; African: n = 5; European: n = 5), and FRMs were isolated from the superficial papillary dermis and deeper reticular dermis and imaged by atomic force microscopy. In the reticular dermis, there was no significant difference in FRM ultrastructure between European and African participants. In contrast, in the more superficial papillary dermis, inter-bead periodicity was significantly larger for FRMs extracted from European participants than from African participants by 2.20 nm (p < .001). We next assessed whether these differences in FRM ultrastructure were present during early postnatal development by characterizing FRMs from full-thickness neonatal foreskin. Analysis of FRM periodicity identified no significant difference between neonatal cohorts (p = .865). These data suggest that at birth, FRMs are developmentally invariant. However, in adults of diverse skin ethnicity, there is a deviation in ultrastructure for the papillary dermal FRMs that may be acquired during the passage of time from child to adulthood. Understanding the mechanism by which this difference in papillary dermal FRMs arises warrants further study.