E-cadherin mediates ultraviolet radiation- and calcium-induced melanin transfer in human skin cells.

Skin pigmentation is directed by epidermal melanin units, characterized by long-lived and dendritic epidermal melanocytes (MC) that interact with viable keratinocytes (KC) to contribute melanin to the epidermis. Previously, we reported that MC:KC contact is required for melanosome transfer that can be enhanced by filopodi, and by UVR/UVA irradiation, which can upregulate melanosome transfer via Myosin X-mediated control of MC filopodia. Both MC and KC express Ca2+ -dependent E-cadherins. These homophilic adhesion contacts induce transient increases in intra-KC Ca2+ , while ultraviolet radiation (UVR) raises intra-MC Ca2+ via calcium-selective ORAI1 ion channels; both are associated with regulating melanogenesis. However, how Ca2+ triggers melanin transfer remains unclear. Here we evaluated the role of E-cadherin in UVR-mediated melanin transfer in human skin cells. MC and KC in human epidermis variably express filopodia-associated E-cadherin, Cdc42, VASP and ß-catenin, all of which were upregulated by UVR in human MC in vitro. Knockdown of E-cadherin revealed that this cadherin is essential for UVR-induced MC filopodia formation and melanin transfer. Moreover, Ca2+ induced a dose-dependent increase in filopodia formation and melanin transfer, as well as increased ß-catenin, Cdc42, Myosin X and E-cadherin expression in these skin cells. Together, these data suggest that filopodial proteins and E-cadherin, which are upregulated by intracellular (UVR-stimulated) and extracellular Ca2+ availability, are required for filopodia formation and melanin transfer. This may open new avenues to explore how Ca2+ signalling influences human pigmentation.

Evaluating the Irritant Factors of Silicone and Hydrocolloid Skin Contact Adhesives Using Trans-Epidermal Water Loss, Protein Stripping, Erythema, and Ease of Removal.

A composite silicone skin adhesive material was designed to improve its water vapor permeability to offer advantages to wearer comfort compared to existing skin adhesive dressings available (including perforated silicone and hydrocolloid products). The chemical and mechanical properties of this novel dressing were analyzed to show that it has a high creep compliance, offering anisotropic elasticity that is likely to place less stress on the skin. A participant study was carried out in which 31 participants wore a novel silicone skin adhesive (Sil2) and a hydrocolloid competitor and were monitored for physiological response to the dressings. Trans-epidermal water loss (TEWL) was measured pre- and postwear to determine impairment of skin barrier function. Sil2 exhibited a higher vapor permeability than the hydrocolloid dressings during wear. Peel strength measurements and dye counter staining of the removed dressings showed that the hydrocolloid had a higher adhesion to the participants' skin, resulting in a greater removal of proteins from the stratum corneum and a higher pain rating from participants on removal. Once the dressings were removed, TEWL of the participants skin beneath the Sil2 was close to normal in comparison to the hydrocolloid dressings that showed an increase in skin TEWL, indicating that the skin had been highly occluded. Analysis of the skin immediately after removal showed a higher incidence of erythema following application of hydrocolloid dressings (>60%) compared to Sil2, (<30%). In summary, this modified silicone formulation demonstrates superior skin protection properties compared to hydrocolloid dressings and is more suitable for use as a skin adhesive.

TDP-43 pathological changes in early onset familial and sporadic Alzheimer's disease, late onset Alzheimer's disease and Down's syndrome: association with age, hippocampal sclerosis and clinical phenotype.

TDP-43 immunoreactive (TDP-43-ir) pathological changes were investigated in the temporal cortex and hippocampus of 11 patients with autosomal dominant familial forms of Alzheimer's disease (FAD), 169 patients with sporadic AD [85 with early onset disease (EOAD) (i.e before 65 years of age), and 84 with late onset after this age (LOAD)], 50 individuals with Down's Syndrome (DS) and 5 patients with primary hippocampal sclerosis (HS). TDP-43-ir pathological changes were present, overall, in 34/180 of AD cases. They were present in 1/11 (9%) FAD, and 9/85 (10%) EOAD patients but were significantly more common (p = 0.003) in LOAD where 24/84 (29%) patients showed such changes. There were no demographic differences, other than onset age, between AD patients with or without TDP-43-ir pathological changes. Double immunolabelling indicated that these TDP-43-ir inclusions were frequently ubiquitinated, but were only rarely AT8 (tau) immunoreactive. Only 3 elderly DS individuals and 4/5 cases of primary HS showed similar changes. Overall, 21.7% of AD cases and 6% DS cases showed hippocampal sclerosis (HS). However, only 9% FAD cases and 16% EOAD cases showed HS, but 29% LOAD cases showed HS. The proportion of EOAD cases with both TDP-43 pathology and HS tended to be greater than those in LOAD, where nearly half of all the cases with TDP-43 pathology did not show HS. The presence of TDP-43-ir changes in AD and DS may therefore be a secondary phenomenon, relating more to ageing than to AD itself. Nevertheless, a challenge to such an interpretation comes from the finding in AD of a strong relationship between TDP-43 pathology and cognitive phenotype. Patients with TDP-43 pathology were significantly more likely to present with an amnestic syndrome than those without (p < 0.0001), in keeping with pathological changes in medial temporal lobe structures. HS was also associated more commonly with an amnestic presentation (p < 0.005), but this association disappeared when TDP-43-positive cases were excluded from the analysis. TDP-43 may, after all, be integral to the pathology of AD, and to some extent determine the clinical phenotype present.

Age-Related Changes in Female Scalp Dermal Sheath and Dermal Fibroblasts: How the Hair Follicle Environment Impacts Hair Aging.

In women, aging leads to reduced hair density and thinner fibers and can result in female-pattern hair loss. However, the impact of the aging dermal environment on female scalp hair follicles remains unclear. In this study, we document in situ changes in 22 women (aged 19-81 years) and primary cultures of dermal fibroblast and dermal sheath cells. In situ, the papillary reticular boundary was indistinguishable in the young scalp but prominent in the scalp of those aged >40 years, accompanied by reduced podoplanin (PDPN) expression, increased versican expression, and changes in collagen organization. Hair follicles were shorter, not reaching the adipose layer. Hyaluronic acid synthase 2 was highly expressed, whereas matrix metalloproteinase 1 was elevated in the dermal papilla and dermal sheath in situ. Primary dermal fibroblast cultures confirmed that matrix metalloproteinase 1 mRNA, MMP1, increased with aging, whereas in dermal sheath cells, hyaluronic acid synthase 2, HAS2, and PDPN increased and α-smooth muscle actin αSMA mRNA decreased. Both exhibited increased cartilage oligomeric protein, COMP mRNA expression. Proteomics revealed an increase in dermal sheath proteins in the dermal fibroblast secretome with aging. In summary, aging female scalp shows striking structural and biological changes in the hair follicle environment that may impact hair growth.

Laser Capture Microdissection on Surgical Tissues to Identify Aberrant Gene Expression in Impaired Wound Healing in Type 2 Diabetes.

The global prevalence Type 2 diabetes mellitus (T2DM) is escalating at a rapid rate. Patients with T2DM suffer from a multitude of complications and one of these is impaired wound healing. This can lead to the development of non-healing sores or foot ulcers and ultimately to amputation. In healthy individuals, wound healing follows a controlled and overlapping sequence of events encompassing inflammation, proliferation, and remodelling. In T2DM, one or more of these steps becomes dysfunctional. Current models to study impaired wound healing in T2DM include in vitro scratch wound assays, skin equivalents, or animal models to examine molecular mechanisms underpinning wound healing and/or potential therapeutic options. However, these do not fully recapitulate the complex wound healing process in T2DM patients, and ex vivo human skin tests are problematic due to the ethics of taking punch biopsies from patients where it is known they will heal poorly. Here, a technique is described whereby expression profiles of the specific cells involved in the (dys)functional wound healing response in T2DM patients can be examined using surplus tissue discarded following amputation or elective cosmetic surgery. In this protocol samples of donated skin are collected, wounded, cultured ex vivo in the air liquid interface, fixed at different time points and sectioned. Specific cell types involved in wound healing (e.g., epidermal keratinocytes, dermal fibroblasts (papillary and reticular), the vasculature) are isolated using laser capture microdissection and differences in gene expression analyzed by sequencing or microarray, with genes of interest further validated by qPCR. This protocol can be used to identify inherent differences in gene expression between both poorly healing and intact skin, in patients with or without diabetes, using tissue ordinarily discarded following surgery. It will yield greater understanding of the molecular mechanisms contributing to T2DM chronic wounds and lower limb loss.

Phosphorylated TDP-43 pathology and hippocampal sclerosis in progressive supranuclear palsy.

TDP-43 is characteristically accumulated in TDP-43 proteinopathies such as frontotemporal lobar degeneration and motor neurone disease, but is also present in some tauopathies, including Alzheimer's disease, argyrophilic grain disease, and corticobasal degeneration (CBD). However, several studies have suggested that cases of progressive supranuclear palsy (PSP) lack TDP-43 pathology. We have therefore examined limbic regions of the brain in 19 PSP cases, as well as in 12 CBD cases, using phosphorylation-dependent anti-TDP-43 antibodies. We observed TDP-43-positive inclusions in five PSP cases (26%), as well as in two CBD cases (17%). The amygdala and hippocampal dentate gyrus were most frequently affected in PSP. Regional tau burden tended to be higher in TDP-43-positive PSP cases, and a significant correlation between tau and TDP-43 burden was noted in the occipitotemporal gyrus. Hippocampal sclerosis (HS) was found in 3/5 TDP-43-positive PSP cases, but HS was significantly more frequent in TDP-43-positive than TDP-43 negative PSP cases. Dementia was present in 13/19 (58%) of the PSP cases, in 4/5 TDP-43-positive cases, in all 3 TDP-43-positive cases with HS, in 1/2 TDP-43-positive cases without HS, and 7/14 cases lacking both. TDP-43 and tau were frequently colocalized in the amygdala, but not in the hippocampal dentate gyrus. Immunoblotting demonstrated the characteristic (for TDP-43 proteinopathies) 45 and 25 kDa bands and high molecular weight smear in the TDP-43-positive PSP case. These findings suggest that (1) although PSP is nominally a tauopathy, pathological TDP-43 can accumulate in the limbic system in some cases, and (2) TDP-43 pathology may be concurrent with HS.

Effect of topographical distribution of α-synuclein pathology on TDP-43 accumulation in Lewy body disease.

It has been reported that the development of TDP-43 pathology in cases of Lewy body disease (LBD) might be associated with the severity of tau pathology. However, the impact of α-synuclein pathology on TDP-43 accumulation in LBD remains unclear. To clarify whether α-synuclein pathology has an effect on TDP-43 accumulation, independent of tau pathology, we examined by immunohistochemistry 56 cases of LBD using a phosphorylation-dependent TDP-43 antibody. The frequency of TDP-43 pathology in all LBD cases was 18% (10/56). In 37 LBD cases with no or low tau burden (LBD-Ltau; Braak NFT stages 0-II), the frequency of TDP-43 pathology was 19% (7/37). The frequency of TDP-43 pathology in diffuse neocortical type LBD-Ltau cases was 36% (4/11), which was higher than those in limbic and brain stem-predominant types (11-14%). The amygdala and entorhinal cortex were the most frequently affected sites of TDP-43 pathology in LBD-Ltau cases. In LBD-Ltau cases, the proportion of diffuse neocortical type LBD was higher in the TDP-43-positive cases, than that in TDP-43-negative cases (57 vs. 23%). In all LBD cases, α-synuclein pathology in the temporal cortex was significantly more severe in TDP-43-positive cases, and significantly correlated with the severity of TDP-43 pathology in the amygdala. In a multivariate model, the presence of severe α-synuclein pathology was significantly associated with the development of TDP-43 pathology independent of age at death and tau pathology. In the amygdala, TDP-43 was often colocalized with α-synuclein or tau. Given these findings, we suggest that α-synuclein pathology is associated with TDP-43 accumulation in LBD cases.

Stress-sensing in the human greying hair follicle: Ataxia Telangiectasia Mutated (ATM) depletion in hair bulb melanocytes in canities-prone scalp.

Canities (or hair greying) is an age-linked loss of the natural pigment called melanin from hair. While the specific cause(s) underlying the loss of melanogenically-active melanocytes from the anagen hair bulbs of affected human scalp remains unclear, oxidative stress sensing appears to be a key factor involved. In this study, we examined the follicular melanin unit in variably pigmented follicles from the aging human scalp of healthy individuals (22-70 years). Over 20 markers were selected within the following categories: melanocyte-specific, apoptosis, cell cycle, DNA repair/damage, senescence and oxidative stress. As expected, a reduction in melanocyte-specific markers in proportion to the extent of canities was observed. A major finding of our study was the intense and highly specific nuclear expression of Ataxia Telangiectasia Mutated (ATM) protein within melanocytes in anagen hair follicle bulbs. ATM is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks and functions as an important sensor of reactive oxygen species (ROS) in human cells. The incidence and expression level of ATM correlated with pigmentary status in canities-affected hair follicles. Moreover, increased staining of the redox-associated markers 8-OHdG, GADD45 and GP-1 were also detected within isolated bulbar melanocytes, although this change was not clearly associated with donor age or canities extent. Surprisingly, we were unable to detect any specific change in the expression of other markers of oxidative stress, senescence or DNA damage/repair in the canities-affected melanocytes compared to surrounding bulbar keratinocytes. By contrast, several markers showed distinct expression of markers for oxidative stress and apoptosis/differentiation in the inner root sheath (IRS) as well as other parts of the hair follicle. Using our in vitro model of primary human scalp hair follicle melanocytes, we showed that ATM expression increased after incubation with the pro-oxidant hydrogen peroxide (H2O2). In addition, this ATM increase was prevented by pre-incubation of cells with antioxidants. The relationship between ATM and redox stress sensing was further evidenced as we observed that the inhibition of ATM expression by chemical inhibition promoted the loss of melanocyte viability induced by oxidative stress. Taken together these new findings illustrate the key role of ATM in the protection of human hair follicle melanocytes from oxidative stress/damage within the human scalp hair bulb. In conclusion, these results highlight the remarkable complexity and role of redox sensing in the status of human hair follicle growth, differentiation and pigmentation.

X-linked retinoschisis: an update.

X-linked retinoschisis is the leading cause of macular degeneration in males and leads to splitting within the inner retinal layers leading to visual deterioration. Many missense and protein truncating mutations have now been identified in the causative retinoschisis gene (RS1) which encodes a 224 amino acid secretory retinal protein, retinoschisin. Retinoschisin octamerisation is implicated in cell-cell interactions and cell adhesion perhaps by interacting with beta2 laminin. Mutations cause loss of retinoschisin function by one of the three mechanisms: by interfering with protein secretion, by preventing its octamerisation or by reducing function in the secreted octamerised protein. The development of retinoschisis mouse models have provided a model system that closely resembles the human disease. Recent reports of RS1 gene transfer to these models and the sustained restoration of some retinal function and morphology suggest gene replacement may be a possible future therapy for patients.

In-depth analysis of molecular alterations within normal and tumour tissue from an entire bronchial tree.

Using laser capture microdissection (LCM), fluorescent microsatellite analysis and immunohistochemical analysis, we have constructed a detailed topographical molecular map of the entire bronchial tree surrounding a primary bronchial squamous carcinoma in order to establish the relationship between the molecular damage within the airway and that in the tumour itself. Allelic imbalance was analysed using markers on chromosomes 3, 9, 13 and 17. In addition, immunohistochemical analysis for p53 and cyclin D1 expression was performed. Analysis revealed allelic imbalance at several loci at the tumour site but also in 83% of the histologically normal airway specimens of the upper and lower lobes. The fractional allele loss (FAL) value was statistically higher (0.75+/-0.13) in the tumour site than in the distal site of the upper (0.42+/-0.09) and lower lobes (0.31+/-0.08). Immunohistochemical analysis revealed overexpression of p53 and cyclin D1 protein within histologically normal bronchial epithelium, thus confirming previous reports for their early involvement in lung tumour development. This is to date the largest in-depth study of allelic imbalance using LCM in a single individual. The patterns of allele-specific imbalance observed support a clonal or oligoclonal expansion model of outgrowths throughout the lung. The widespread incidence of genetic changes in the whole of lung most likely represents smoking-induced alterations and emphasize the complexity of the field cancerization concept. Our findings point to the need for in-depth studies of the whole bronchial tree tissue surrounding lung carcinomas, in order to identify the genetic changes that differentiate preneoplastic and neoplastic stages in lung carcinogenesis.

In vitro and ex vivo examination of topical Pomiferin treatments.

Pomiferin is a unique, prenylated isoflavonoid that can be isolated and purified from the fruits of Maclura pomifera (Osage Orange). The molecule typically is isolated with a small amount of a molecule called Osajin which is structurally similar to Pomiferin but lacks an aromatic hydroxyl group. As a consequence, Osajin has been shown to be a less effective antioxidant than Pomiferin. In vitro studies on Normal Human Dermal Fibroblasts demonstrate that Pomiferin is a potent extracellular matrix protein stimulant, showing increases in collagen, elastin and fibrillin expression comparable or superior to equivalent concentrations of retinol. Ex vivo hair follicle assays demonstrate comparable effects on expression of collagen and elastin at Pomiferin concentrations in the range of 0.05-5 ppm. Taken together, the results from the two assays conducted on different models indicate that Pomiferin may be a very interesting ingredient for topical skin and scalp treatments where modulation of the expression of extracellular matrix proteins is important.

Lysophosphatidic acid promotes cell migration through STIM1- and Orai1-mediated Ca2+(i) mobilization and NFAT2 activation.

Lysophosphatidic acid (LPA) enhances cell migration and promotes wound healing in vivo, but the intracellular signaling pathways regulating these processes remain incompletely understood. Here we investigated the involvement of agonist-induced Ca(2+) entry and STIM1 and Orai1 proteins in regulating nuclear factor of activated T cell (NFAT) signaling and LPA-induced keratinocyte cell motility. As monitored by Fluo-4 imaging, stimulation with 10 µM LPA in 60 µM Ca(2+)(o) evoked Ca(2+)(i) transients owing to store release, whereas addition of LPA in physiological 1.2 mM Ca(2+)(o) triggered store release coupled to extracellular Ca(2+) entry. Store-operated Ca(2+) entry (SOCE) was blocked by the SOCE inhibitor diethylstilbestrol (DES), STIM1 silencing using RNA interference (RNAi), and expression of dominant/negative Orai1(R91W). LPA induced significant NFAT activation as monitored by nuclear translocation of green fluorescent protein-tagged NFAT2 and a luciferase reporter assay, which was impaired by DES, expression of Orai1(R91W), and inhibition of calcineurin using cyclosporin A (CsA). By using chemotactic migration assays, LPA-induced cell motility was significantly impaired by STIM1, CsA, and NFAT2 knockdown using RNAi. These data indicate that in conditions relevant to epidermal wound healing, LPA induces SOCE and NFAT activation through Orai1 channels and promotes cell migration through a calcineurin/NFAT2-dependent pathway.

Ubiquitin associated protein 1 is a risk factor for frontotemporal lobar degeneration.

Frontotemporal lobar degeneration (FTLD) is now recognised as a common form of early onset dementia. Up to 40% of patients have a family history of disease demonstrating a large genetic component to its etiology. Linkage to chromosome 9p21 has recently been reported in families with this disorder. We undertook a large scale two-stage linkage disequilibrium mapping approach of this region in the Manchester FTLD cohort. We identified association of ubiquitin associated protein 1 (UBAP1; OR 1.42 95% CI 1.08-1.88, P=0.013) with FTLD in this cohort and we replicated this finding in an additional two independent cohorts from the Netherlands (OR 1.33 95% CI 1.04-1.69, P=0.022), the USA (OR 1.4 95% CI 1.02-1.92, P=0.032) and a forth Spanish cohort approached significant association (OR 1.45 95% CI 0.97-2.17, P=0.064). However, we failed to replicate in a fifth cohort from London (OR 0.99 95% CI 0.72-1.37, P=0.989). Quantitative analysis of UBAP1 mRNA extracted from tissue from the Manchester cases demonstrated a significant reduction of expression from the disease-associated haplotype. In addition, we identified a case of familial FTLD that demonstrated colocalisation of UBAP1 and TDP-43 in the neuronal cytoplasmic inclusions in the brain of this individual. Our data for the first time identifies UBAP1 as a genetic risk factor for FTLD and suggests a mechanistic relationship between this protein and TDP-43.

The genetics of frontotemporal lobar degeneration.

PURPOSE OF REVIEW: This review addresses the latest developments in the genetics of frontotemporal lobar degeneration. 'Frontotemporal lobar degeneration' is the clinical term used to describe a heterogeneous neurodegenerative syndrome that includes frontotemporal dementia, semantic dementia, progressive nonfluent aphasia and progressive apraxia. Up to 40% of patients with frontotemporal lobar degeneration have a family history of a similar disorder in a first-degree relative, highlighting a significant genetic contribution to the aetiology of this disorder. RECENT FINDINGS: Four genes that cause autosomal frontotemporal lobar degeneration have already been identified, including two that are only 1.7 megabases apart on chromosome 17. SUMMARY: Although much progress has been made in our understanding of the genetics of frontotemporal lobar degeneration in recent years, the majority of the genetic causes of this syndrome remains to be identified.