Epidermolysis bullosa - a group of skin diseases with different causes but commonalities in gene expression

Multifaceted functions of RPS27a: An unconventional ribosomal protein

The ribosomal protein S27a (RPS27a) is cleaved from the fusion protein ubiquitin-RPS27a (Ub-RPS27a). Generally, Ub and RPS27a are coexpressed as a fusion protein but function independently after Ub is cleaved from RPS27a by a deubiquitinating enzyme. As an RP, RPS27a assembles into ribosomes, but it also functions independently of ribosomes. RPS27a is involved in the development and poor prognosis of various cancers, such as colorectal cancer, liver cancer, chronic myeloid leukemia, and renal carcinoma, and is associated with poor prognosis. Notably, the murine double minute 2/P53 axis is a major pathway through which RPS27a regulates cancer development. Moreover, RPS27a maintains sperm motility, regulates winged aphid indirect flight muscle degeneration, and facilitates plant growth. Additionally, RPS27a is a metalloprotein and mercury (Hg) biomarker. In the present review, we described the origin, structure, and biological functions of RPS27a.

Cutaneous Wound Healing: An Update from Physiopathology to Current Therapies

The skin is the biggest organ of human body which acts as a protective barrier against deleterious agents. When this barrier is damaged, the organism promotes the healing process with several molecular and cellular mechanisms, in order to restore the physiological structure of the skin. The physiological control of wound healing depends on the correct balance among its different mechanisms. Any disruption in the balance of these mechanisms can lead to problems and delay in wound healing. The impairment of wound healing is linked to underlying factors as well as aging, nutrition, hypoxia, stress, infections, drugs, genetics, and chronic diseases. Over the years, numerous studies have been conducted to discover the correct approach and best therapies for wound healing, including surgical procedures and non-surgical treatments such as topical formulations, dressings, or skin substitutes. Thus, this general approach is necessary to facilitate the direction of further studies. This work provides updated concepts of physiological mechanisms, the factors that can interfere, and updated treatments used in skin wound healing.

The Effect of Comorbidities on Wound Healing

Wound healing is affected by several factors. Preexisting diagnoses may significantly alter, delay, or inhibit normal wound healing. This is most commonly seen with chronic disorders, such as diabetes and renal failure, but also occurs secondary to aging and substance abuse. Less commonly, genetic or inflammatory disorders are the cause of delayed wound healing. In some cases, it is not the illness, but the treatment that can inhibit wound healing. This is seen in patients getting chemotherapy, radiation, steroids, methotrexate, and a host of other medications. Understanding these processes may help treat or avoid wound healing problems.

Combinatorial Omics Analysis Reveals Perturbed Lysosomal Homeostasis in Collagen VII-deficient Keratinocytes

The extracellular matrix protein collagen VII is part of the microenvironment of stratified epithelia and critical in organismal homeostasis. Mutations in the encoding gene COL7A1 lead to the skin disorder dystrophic epidermolysis bullosa (DEB), are linked to skin fragility and progressive inflammation-driven fibrosis that facilitates aggressive skin cancer. So far, these changes have been linked to mesenchymal alterations, the epithelial consequences of collagen VII loss remaining under-addressed. As epithelial dysfunction is a principal initiator of fibrosis, we performed a comprehensive transcriptome and proteome profiling of primary human keratinocytes from DEB and control subjects to generate global and detailed images of dysregulated epidermal molecular pathways linked to loss of collagen VII. These revealed downregulation of interaction partners of collagen VII on mRNA and protein level, but also increased abundance of S100 pro-inflammatory proteins in primary DEB keratinocytes. Increased TGF-β signaling because of loss of collagen VII was associated with enhanced activity of lysosomal proteases in both keratinocytes and skin of collagen VII-deficient individuals. Thus, loss of a single structural protein, collagen VII, has extra- and intracellular consequences, resulting in inflammatory processes that enable tissue destabilization and promote keratinocyte-driven, progressive fibrosis.

Minor collagens of the skin with not so minor functions

The structure and function of the skin relies on the complex expression pattern and organisation of extracellular matrix macromolecules, of which collagens are a principal component. The fibrillar collagens, types I and III, constitute over 90% of the collagen content within the skin and are the major determinants of the strength and stiffness of the tissue. However, the minor collagens also play a crucial regulatory role in a variety of processes, including cell anchorage, matrix assembly, and growth factor signalling. In this article, we review the expression patterns, key functions and involvement in disease pathogenesis of the minor collagens found in the skin. While it is clear that the minor collagens are important mediators of normal tissue function, homeostasis and repair, further insight into the molecular level structure and activity of these proteins is required for translation into clinical therapies.

Tissue-engineered human psoriatic skin supplemented with cytokines as an in vitro model to study plaque psoriasis

AIM

Psoriasis is a chronic inflammatory skin disease. To study its complex etiology, a psoriatic skin substitute model supplemented with a cytokine cocktail has been used.

MATERIALS & METHODS

Reconstructed psoriatic skin substitutes were supplemented with a cocktail of four cytokines: TNF-α, IL-1α, IL-6 and IL-17A, to monitor their impact on gene expression by DNA microarray.

RESULTS

Gene profiling analyses identified several deregulated genes reported as being also deregulated in psoriasis skin in vivo (S100A12, IL-8, DEFB4A and KYNU). The expression of those genes was dramatically increased compared with basal levels of controls (p < 0.005 to < 0.05).

CONCLUSION

Psoriatic substitutes supplemented with a cocktail of TNF-α, IL-1α, IL-6 and IL-17A showed similar transcriptome alterations to those found in psoriasis.

Gene therapy: pursuing restoration of dermal adhesion in recessive dystrophic epidermolysis bullosa

The replacement of a defective gene with a fully functional copy is the goal of the most basic gene therapy. Recessive dystrophic epidermolysis bullosa (RDEB) is characterised by a lack of adhesion of the epidermis to the dermis. It is an ideal target for gene therapy as all variants of hereditary RDEB are caused by mutations in a single gene, COL7A1, coding for type VII collagen, a key component of anchoring fibrils that secure attachment of the epidermis to the dermis. RDEB is one of the most severe variants in the epidermolysis bullosa (EB) group of heritable skin diseases. Epidermolysis bullosa is defined by chronic fragility and blistering of the skin and mucous membranes due to mutations in the genes responsible for production of the basement membrane proteins. This condition has a high personal, medical and socio-economic impact. People with RDEB require a broad spectrum of medications and specialised care. Due to this being a systemic condition, most research focus is in the area of gene therapy. Recently, preclinical works have begun to show promise. They focus on the virally mediated ex vivo correction of autologous epithelium. These corrected cells are then to be expanded and grafted onto the patient following the lead of the first successful gene therapy in dermatology being a grafting of corrected tissue for junctional EB treatment. Current progress, outstanding challenges and future directions in translating these approaches in clinics are reviewed in this article.

In vitro analysis of photosensitizer accumulation for assessment of applicability of fluorescence diagnosis of squamous cell carcinoma of epidermolysis bullosa patients

Epidermolysis bullosa (EB) is a group of inherited skin disorders characterized by blistering following mechanical trauma. Chronic wounds of EB patients often lead to tumors such as squamous cell carcinoma (SCC). Early diagnosis may prevent its invasive growth--frequently the reason of premature mortality of EB-patients. Early detection of tumors is achieved by fluorescence diagnosis (FD), where photosensitizers localize selectively in tumors and fluoresce upon illumination. Excessive accumulation of photosensitizers in inflamed areas, as occasionally found at chronic wounds and tumors due to inflammatory processes, leads to false-positive results in FD. This study analyzed accumulation kinetics of the photosensitizers hypericin and endogenous protoporphyrin IX (PpIX) in different skin cell lines including the three EB subtypes under normal and proinflammatory conditions (stimulated with TNF-alpha). The aim was to assess the applicability of FD of SCC in EB. All cell lines accumulate hypericin or PpIX mostly increasing with incubation time, but with different kinetics. SCC cells of recessive dystrophic EB (RDEB) accumulate less hypericin or PpIX than nonmalignant RDEB cells. Nevertheless, tumor selectivity in vivo might be existent. Non-EB cell lines are more active concerning photosensitizer enrichment. Proinflammatory conditions of skin cell lines seem to have no major influence on photosensitizer accumulation.

The G0/G1 switch gene 2 (G0S2): regulating metabolism and beyond

The G0/G1 switch gene 2 (G0S2) was originally identified in blood mononuclear cells following induced cell cycle progression. Translation of G0S2 results in a small basic protein of 103 amino acids in size. It was initially believed that G0S2 mediates re-entry of cells from the G0 to G1 phase of the cell cycle. Recent studies have begun to reveal the functional aspects of G0S2 and its protein product in various cellular settings. To date the best-known function of G0S2 is its direct inhibitory capacity on the rate-limiting lipolytic enzyme adipose triglyceride lipase (ATGL). Other studies have illustrated key features of G0S2 including sub-cellular localization, expression profiles and regulation, and possible functions in cellular proliferation and differentiation. In this review we present the current knowledge base regarding all facets of G0S2, and pose a variety of questions and hypotheses pertaining to future research directions.