One gene but different proteins and diseases: the complexity of dystonin and bullous pemphigoid antigen 1

Paxbp1 is indispensable for the maintenance of epidermal homeostasis

The mammalian epidermis is a structurally complex tissue that serves critical barrier functions, safeguarding the organism from the external milieu. The development of the epidermis is governed by sophisticated regulatory processes. However, the precise mechanism maintaining epidermal homeostasis remains incompletely elucidated. Recent studies have identified Paxbp1, an evolutionarily conserved protein, as being involved in the developmental regulation of various cells, tissues, and organs. Nonetheless, its role in skin development has not been explored. Here, we report that the targeted deletion of Paxbp1 in epidermal keratinocytes mediated by Keratin14-Cre leads to severe disruption in skin architecture. Mice deficient in Paxbp1 exhibited a substantially reduced epidermal thickness and pronounced separation at the dermo-epidermal junction upon birth. Mechanistically, we demonstrate that the absence of Paxbp1 hinders cellular proliferation, marked by a halt in cell cycle transition, suppressed gene expression of proliferation, and a compromised DNA replication pathway in basal keratinocytes, resulting in the thinning of the skin epidermis. Moreover, molecules and pathways associated with hemidesmosome assembly were impaired in Paxbp1-deficient keratinocytes, culminating in the detachment of the skin epidermal layer. Therefore, our study highlights an indispensable role of Paxbp1 in the maintenance of epidermal homeostasis.

Sensory-motor circuit is a therapeutic target for dystonia musculorum mice, a model of hereditary sensory and autonomic neuropathy 6

Mutations in Dystonin (DST), which encodes cytoskeletal linker proteins, cause hereditary sensory and autonomic neuropathy 6 (HSAN-VI) in humans and the dystonia musculorum (dt) phenotype in mice; however, the neuronal circuit underlying the HSAN-VI and dt phenotype is unresolved. dt mice exhibit dystonic movements accompanied by the simultaneous contraction of agonist and antagonist muscles and postnatal lethality. Here, we identified the sensory-motor circuit as a major causative neural circuit using a gene trap system that enables neural circuit-selective inactivation and restoration of Dst by Cre-mediated recombination. Sensory neuron-selective Dst deletion led to motor impairment, degeneration of proprioceptive sensory neurons, and disruption of the sensory-motor circuit. Restoration of Dst expression in sensory neurons using Cre driver mice or a single postnatal injection of Cre-expressing adeno-associated virus ameliorated sensory degeneration and improved abnormal movements. These findings demonstrate that the sensory-motor circuit is involved in the movement disorders in dt mice and that the sensory circuit is a therapeutic target for HSAN-VI.

Roles of dystonin isoforms in the maintenance of neural, muscle, and cutaneous tissues

Dystonin (DST), also known as bullous pemphigoid antigen 1 (BPAG1), encodes cytoskeletal linker proteins belonging to the plakin family. The DST gene produces several isoforms, including DST-a, DST-b, and DST-e, which are expressed in neural, muscle, and cutaneous tissues, respectively. Pathogenic DST mutations cause hereditary sensory and autonomic neuropathy type 6 (HSAN-VI) and epidermolysis bullosa simplex (EBS); therefore, it is important to elucidate the roles of DST isoforms in multiple organs. Recently, we have used several Dst mutant mouse strains, in which the expression of Dst isoforms is disrupted in distinct patterns, to gain new insight into how DST functions in multiple tissues. This review provides an overview of the roles played by tissue-specific DST isoforms in neural, muscle, and cutaneous tissues.

Pemphigus and pemphigoid are associated with Alzheimer's disease in older adults: evidence from the US Nationwide inpatient sample 2016-2018

BACKGROUND

Pemphigus and pemphigoid are rare autoimmune skin disorders caused by autoantibodies against structural proteins and characterized by blistering of the skin and/or mucous membranes. Associations have been noted between skin diseases and Alzheimer's dementia (AD). Dementia is a neurological disorder of progressive cognitive impairment with increasing incidence among older adults. This study aimed to assess the potential associations between pemphigus, pemphigoid and AD in a large, nationally representative US cohort.

METHODS

All data of hospitalized patients aged 60 years or older were extracted from the US Nationwide Inpatient Sample (NIS) database 2016-2018. Patients with a history of head trauma, diagnosis of vascular dementia, history of cerebrovascular disease, or malformation of cerebral vessels were excluded. The study population was divided into those with and without pemphigus (cohort 1) and with and without pemphigoid (cohort 2).

RESULTS

Pemphigus was independently associated with a 69% increased risk of AD. Adults ≥80 years old with pemphigus were 72% more likely to develop AD than adults without pemphigus. Women with pemphigus were 78% more likely to develop AD than women without pemphigus. On the other hand, pemphigoid was independently associated with a 39% increased risk for AD and subjects ≥80 years with pemphigoid were 40% more likely to have AD than those without pemphigoid. Females with pemphigoid were 63% more likely to have AD than those without pemphigoid. Moreover, Hispanic older adults with pemphigus were 3-times more likely to have AD than those without pemphigoid.

CONCLUSIONS

Pemphigus and pemphigoid were both independently associated with AD in older adults, especially among females and octogenarians. Further studies addressing the etiology and mechanisms underlying these associations are highly warranted.

Dystonin modifiers of junctional epidermolysis bullosa and models of epidermolysis bullosa simplex without dystonia musculorum

The Lamc2jeb junctional epidermolysis bullosa (EB) mouse model has been used to demonstrate that significant genetic modification of EB symptoms is possible, identifying as modifiers Col17a1 and six other quantitative trait loci, several with strong candidate genes including dystonin (Dst/Bpag1). Here, CRISPR/Cas9 was used to alter exon 23 in mouse skin specific isoform Dst-e (Ensembl GRCm38 transcript name Dst-213, transcript ID ENSMUST00000183302.5, protein size 2639AA) and validate a proposed arginine/glutamine difference at amino acid p1226 in B6 versus 129 mice as a modifier of EB. Frame shift deletions (FSD) in mouse Dst-e exon 23 (Dst-eFSD/FSD) were also identified that cause mice carrying wild-type Lamc2 to develop a phenotype similar to human EB simplex without dystonia musculorum. When combined, Dst-eFSD/FSD modifies Lamc2jeb/jeb (FSD+jeb) induced disease in unexpected ways implicating an altered balance between DST-e (BPAG1e) and a rarely reported rodless DST-eS (BPAG1eS) in epithelium as a possible mechanism. Further, FSD+jeb mice with pinnae removed are found to provide a test bed for studying internal epithelium EB disease and treatment without severe skin disease as a limiting factor while also revealing and accelerating significant nasopharynx symptoms present but not previously noted in Lamc2jeb/jeb mice.

The DST gene in neurobiology

DST is a gene whose alternative splicing yields epithelial, neuronal, and muscular isoforms. The autosomal recessive Dstdt (dystonia musculorum) spontaneous mouse mutation causes degeneration of spinocerebellar tracts as well as peripheral sensory nerves, dorsal root ganglia, and cranial nerve ganglia. In addition to Dstdt mutants, axonopathy and neurofilament accumulation in perikarya are features of two other murine lines with spontaneous Dst mutations, targeted Dst knockout mice, DstTg4 transgenic mice carrying two deleted Dst exons, DstGt mice with trapped actin-binding domain-containing isoforms, and conditional Schwann cell-specific Dst knockout mice. As a result of nerve damage, Dstdt mutants display dystonia and ataxia, as seen in several genetically modified models and their motor coordination deficits have been quantified along with the spontaneous Dst nonsense mutant, the conditional Schwann cell-specific Dst knockout, the conditional DstGt mutant, and the Dst-b isoform specific Dst mutant. Recent findings in humans have associated DST mutations of the Dst-b isoform with hereditary sensory and autonomic neuropathies type 6 (HSAN-VI). These data should further encourage the development of genetic techniques to treat or prevent ataxic and dystonic symptoms.

Novel genetic variants associated with inhaled corticosteroid treatment response in older adults with asthma

INTRODUCTION

Older adults have the greatest burden of asthma and poorest outcomes. The pharmacogenetics of inhaled corticosteroid (ICS) treatment response is not well studied in older adults.

METHODS

A genome-wide association study of ICS response was performed in asthmatics of European ancestry in Genetic Epidemiology Research on Adult Health and Aging (GERA) by fitting Cox proportional hazards regression models, followed by validation in the Mass General Brigham (MGB) Biobank and Rotterdam Study. ICS response was measured using two definitions in asthmatics on ICS treatment: (1) absence of oral corticosteroid (OCS) bursts using prescription records and (2) absence of asthma-related exacerbations using diagnosis codes. A fixed-effect meta-analysis was performed for each outcome. The validated single-nucleotide polymorphisms (SNPs) were functionally annotated to standard databases.

RESULTS

In 5710 subjects in GERA, 676 subjects in MGB Biobank, and 465 subjects in the Rotterdam Study, four novel SNPs on chromosome six near PTCHD4 validated across all cohorts and met genome-wide significance on meta-analysis for the OCS burst outcome. In 4541 subjects in GERA and 505 subjects in MGB Biobank, 152 SNPs with p<5 × 10-5 were validated across these two cohorts for the asthma-related exacerbation outcome. The validated SNPs included methylation and expression quantitative trait loci for CPED1, CRADD and DST for the OCS burst outcome and GM2A, SNW1, CACNA1C, DPH1, and RPS10 for the asthma-related exacerbation outcome.

CONCLUSIONS

Multiple novel SNPs associated with ICS response were identified in older adult asthmatics. Several SNPs annotated to genes previously associated with asthma and other airway or allergic diseases, including PTCHD4.

Brain MRI findings in patients with bullous pemphigoid: A case-control study

Evidence suggests that bullous pemphigoid (BP) is associated with multiple neurological disorders. We aimed to compare brain magnetic resonance (MRI) findings between BP patients and a control group. This case-control study included patients with BP referred to two dermatology clinics during a two-year period. A group of individuals attending the same clinics for cosmetic procedures were selected as controls. First, participants' general information including age, gender, education, weight and underlying disease was recorded. For BP patients, the drugs and the BP Disease Area Index (BPDAI) were recorded as well. Then, all participants underwent brain MRI without contrast. The Fazekas scale, the general cerebral atrophy (GCA) score, and the Medial Temporal lobe Atrophy (MTA) score were used to assess MRI images. Overall, 24 BP patients and 24 controls were evaluated in this study. Both groups were comparable regarding age, gender and education. However, diabetes and hypertension were more frequent in the control group. The mean BPDAI total score was 51.39 ± 68.92 in BP patients and most of them used rituximab (41.7%). None of the participants had MS or Alzheimer MRI patterns. There was no difference between groups in terms of GCA and MTA scores. Furthermore, the frequency of partially empty sella did not differ significantly between BP patients and controls (p = 0.461); nevertheless, grade-3 Fazekas was significantly higher in BP patients compared to controls (25% vs. 0%, p = 0.019). Of note, one BP patient had an epidermoid cyst and another had moderate enlargement of three ventricles. Also, new infarcts were observed in two and old infarcts in four BP patients. Although the majority of abnormal brain MRI findings were more frequent in BP patients compared to controls, only grade-3 Fazekas was significantly higher and acute infarcts were exclusively observed in BP patients.

Isoform-specific mutation in Dystonin-b gene causes late-onset protein aggregate myopathy and cardiomyopathy

Dystonin (DST), which encodes cytoskeletal linker proteins, expresses three tissue-selective isoforms: neural DST-a, muscular DST-b, and epithelial DST-e. DST mutations cause different disorders, including hereditary sensory and autonomic neuropathy 6 (HSAN-VI) and epidermolysis bullosa simplex; however, etiology of the muscle phenotype in DST-related diseases has been unclear. Because DST-b contains all of the DST-a-encoding exons, known HSAN-VI mutations could affect both DST-a and DST-b isoforms. To investigate the specific function of DST-b in striated muscles, we generated a Dst-b-specific mutant mouse model harboring a nonsense mutation. Dst-b mutant mice exhibited late-onset protein aggregate myopathy and cardiomyopathy without neuropathy. We observed desmin aggregation, focal myofibrillar dissolution, and mitochondrial accumulation in striated muscles, which are common characteristics of myofibrillar myopathy. We also found nuclear inclusions containing p62, ubiquitin, and SUMO proteins with nuclear envelope invaginations as a unique pathological hallmark in Dst-b mutation-induced cardiomyopathy. RNA-sequencing analysis revealed changes in expression of genes responsible for cardiovascular functions. In silico analysis identified DST-b alleles with nonsense mutations in populations worldwide, suggesting that some unidentified hereditary myopathy and cardiomyopathy are caused by DST-b mutations. Here, we demonstrate that the Dst-b isoform is essential for long-term maintenance of striated muscles.

Deciphering the Contribution of BP230 Autoantibodies in Bullous Pemphigoid

Bullous pemphigoid (BP) is a subepidermal autoimmune blistering disease predominantly affecting elderly patients and carries significant morbidity and mortality. Patients typically suffer from severe itch with eczematous lesions, urticarial plaques, and/or tense blisters. BP is characterized by the presence of circulating autoantibodies against two components of the hemidesmosome, BP180 and BP230. The transmembrane BP180, also known as type XVII collagen or BPAG2, represents the primary pathogenic autoantigen in BP, whereas the intracellular BP230 autoantigen is thought to play a minor role in disease pathogenesis. Although experimental data exist suggesting that anti-BP230 antibodies are secondarily formed following initial tissue damage mediated by antibodies targeting extracellular antigenic regions of BP180, there is emerging evidence that anti-BP230 IgG autoantibodies alone directly contribute to tissue damage. It has been further claimed that a subset of patients has a milder variant of BP driven solely by anti-BP230 autoantibodies. Furthermore, the presence of anti-BP230 autoantibodies might correlate with distinct clinical features. This review summarizes the current understanding of the role of BP230 and anti-BP230 antibodies in BP pathogenesis.

Ancient Origins of Cytoskeletal Crosstalk: Spectraplakin-like Proteins Precede the Emergence of Cortical Microtubule Stabilization Complexes as Crosslinkers

Adhesion between cells and the extracellular matrix (ECM) is one of the prerequisites for multicellularity, motility, and tissue specialization. Focal adhesions (FAs) are defined as protein complexes that mediate signals from the ECM to major components of the cytoskeleton (microtubules, actin, and intermediate filaments), and their mutual communication determines a variety of cellular processes. In this study, human cytoskeletal crosstalk proteins were identified by comparing datasets with experimentally determined cytoskeletal proteins. The spectraplakin dystonin was the only protein found in all datasets. Other proteins (FAK, RAC1, septin 9, MISP, and ezrin) were detected at the intersections of FAs, microtubules, and actin cytoskeleton. Homology searches for human crosstalk proteins as queries were performed against a predefined dataset of proteomes. This analysis highlighted the importance of FA communication with the actin and microtubule cytoskeleton, as these crosstalk proteins exhibit the highest degree of evolutionary conservation. Finally, phylogenetic analyses elucidated the early evolutionary history of spectraplakins and cortical microtubule stabilization complexes (CMSCs) as model representatives of the human cytoskeletal crosstalk. While spectraplakins probably arose at the onset of opisthokont evolution, the crosstalk between FAs and microtubules is associated with the emergence of metazoans. The multiprotein complexes contributing to cytoskeletal crosstalk in animals gradually gained in complexity from the onset of metazoan evolution.

Pathogenic DST sequence variants result in either epidermolysis bullosa simplex (EBS) or hereditary sensory and autonomic neuropathy type 6 (HSAN-VI)

DST encodes bullous pemphigoid antigen-1 (BPAG1), a protein with eight tissue-specific isoforms expressed in the skin, muscle, brain, and nerves. Accordingly, mutations in this gene are associated with epidermolysis bullosa simplex (EBS) and hereditary sensory and autonomic neuropathy type 6 (HSAN-VI). The genotypic spectrum is attested to by 19 distinct mutations but genotype-phenotype correlation for both disorders is not well established. In this study, we performed next-generation sequencing (NGS) on two families with different phenotypic presentations, one fetus (P1) with musculoskeletal and neurological malformations established by prenatal ultrasound and family history, and a 15-year-old female (P2) with skin blistering. P1 had a novel homozygous nonsense mutation, DST: NM_001144769, c.3805C>T, p.R1269* within a region of homozygosity (ROH). This mutation resides within the plakin domain of BPAG1 and ablates all isoforms of this protein, leading to novel extracutaneous phenotypes consistent with HSAN-VI in P1. P2 had a recurrent homozygous mutation DST: NM_001723.7, c.3370C>T, p.Gln1124* that presented with giant, trauma-induced skin blisters without extracutaneous involvement. This mutation is located within the coiled-coil domain present on the skin isoform of DST, BPGA1-e, associated with EBS. In summary, we report two families with pathogenic DST variants and expand the spectrum of DST genotype and phenotypes.

Neurological and psychiatric comorbidities in bullous pemphigoid

Introduction: Bullous pemphigoid (BP) is an autoimmune skin disease that typically presents with severe itching and blistering, with or without eczematous and urticarial lesions. Patients with BP are at an increased risk of comorbid conditions, especially neurologic and psychiatric diseases. Several recent studies have found a link between BP and neurological disorders, especially stroke, dementia, and Parkinson's disease. The aim of our study was to evaluate the prevalence of neurological and psychiatric comorbidities and their treatment in BP patients. Methods: A cross-sectional, observational, descriptive study was conducted based on the analysis of the medical records of 105 patients with confirmed BP. Demographic and clinical data on BP, neurological and psychiatric comorbidities were collected and statistically analyzed for all patients. Results: The median age was 77.8±10.6 years (range, 39-98 years). Among the study group, 71 (67,61%) patients had neurological comorbidity. Comorbidity with the highest frequency was ischemic stroke found in 28 (26,67%) patients, followed by dementia in 27 (25,71%), Alzheimer's in 11 (10,48%) and Parkinson's disease 5 (4,76%) patients. It was noted that there was a statistically significant difference among male and female patients with Alzheimer's disease (p = 0,0046) and psychiatric disorder (p = 0,044). Conclusion: Neurological disorders usually precede the diagnosis of BP, and mortality may be higher in patients with comorbid conditions. Clinicians should be aware of the early signs and symptoms of BP, primarily in patients with primary neurological disorders such as dementia, stroke, or Parkinson's disease.

The Relationship Between Alzheimer's Disease and Skin Diseases: A Review

Alzheimer's disease is the most common type of dementia placing a heavy burden on the healthcare system worldwide. Skin diseases are also one of the most common health problems. Several skin diseases are associated with Alzheimer's disease through different mechanisms. This review summarizes the relationship between Alzheimer's disease and several types of skin diseases, including bullous pemphigoid, hidradenitis suppurativa, psoriasis, skin cancer, and cutaneous amyloidosis, and provides suggestions based on these associations. Neurologists, dermatologists, and general practitioners should be aware of the relationship between Alzheimer's disease and skin diseases. Dermatology/neurology consultation or referral is necessary when needed.

Genetic mapping and phenotypic analysis of shotH.3.2 in Drosophila melanogaster

Genetic screens are used to identify genes involved in specific biological processes. An EMS mutagenesis screen in Drosophila melanogaster identified growth control phenotypes in the developing eye. One mutant line from this screen, H.3.2, was phenotypically characterized using the FLP/FRT system and genetically mapped by complementation analysis and genomic sequencing by undergraduate students participating in the multi-institution Fly-CURE consortium. H.3.2 was found to have a nonsense mutation in short stop (shot), anortholog of the mammalian spectraplakin dystonin (DST). shot and DST are involved in cytoskeletal organization and play roles during cell growth and proliferation.

Coexistence of bullous pemphigoid with neuropsychiatric comorbidities is associated with anti-BP230 seropositivity

BACKGROUND

While clustering of bullous pemphigoid (BP) with neuropsychiatric diseases is well-established, the clinical and immunological profile of BP patients with this comorbidity remains to be decisively determined.

OBJECTIVES

To evaluate the burden of neurological and psychiatric comorbidities among patients with BP and to elucidate the clinical, immunological and immunopathological features of patients with BP and comorbid neuropsychiatric conditions.

METHODS

We performed a retrospective study encompassing patients diagnosed with BP throughout the years 2009-2020 in a specialized tertiary referral centre. Multivariate logistic regression model was used to identify predictors of neuropsychiatric conditions among patients with BP.

RESULTS

The study included 273 patients with BP, of whom 123 (45.1%) presented with comorbid neuropsychiatric disease. Compared to the remaining patients with BP (n = 150), those with pre-existing neuropsychiatric diseases demonstrated older mean [standard deviation (SD)] age [81.7 (9.1) vs. 76.9 (10.1); P < 0.001], female preponderance (65.0% vs. 49.3%; P = 0.009), higher seropositivity rate of anti-BP230 (67.7% vs. 36.5%; P = 0.006) and higher levels of anti-BP180 NC16A IgG [651.3 (1279.6) vs. 370.4 (818.6) U/mL; P = 0.039]. In multivariate analysis, anti-BP230 seropositivity was independently associated with coexistence of BP with neuropsychiatric conditions [adjusted odds ratio (OR), 3.43; 95% CI, 1.24-9.52; P = 0.018]. In a sensitivity analysis confined to patients with neurological diseases (n = 103), older age [82.1 (8.4) vs. 77.2 (10.3); P < 0.001] and increased anti-BP230 seropositivity (68.0% vs. 39.7%; P = 0.018) were identified.

CONCLUSIONS

The coexistence of BP with neuropsychiatric diseases is independently associated with the generation of anti-BP230 antibodies.

Human gastrointestinal epithelia of the esophagus, stomach, and duodenum resolved at single-cell resolution

The upper gastrointestinal tract, consisting of the esophagus, stomach, and duodenum, controls food transport, digestion, nutrient uptake, and hormone production. By single-cell analysis of healthy epithelia of these human organs, we molecularly define their distinct cell types. We identify a quiescent COL17A1high KRT15high stem/progenitor cell population in the most basal cell layer of the esophagus and detect substantial gene expression differences between identical cell types of the human and mouse stomach. Selective expression of BEST4, CFTR, guanylin, and uroguanylin identifies a rare duodenal cell type, referred to as BCHE cell, which likely mediates high-volume fluid secretion because of continual activation of the CFTR channel by guanylin/uroguanylin-mediated autocrine signaling. Serotonin-producing enterochromaffin cells in the antral stomach significantly differ in gene expression from duodenal enterochromaffin cells. We, furthermore, discover that the histamine-producing enterochromaffin-like cells in the oxyntic stomach express the luteinizing hormone, yet another member of the enteroendocrine hormone family.

Zmat3 Is a Key Splicing Regulator in the p53 Tumor Suppression Program

Although TP53 is the most commonly mutated gene in human cancers, the p53-dependent transcriptional programs mediating tumor suppression remain incompletely understood. Here, to uncover critical components downstream of p53 in tumor suppression, we perform unbiased RNAi and CRISPR-Cas9-based genetic screens in vivo. These screens converge upon the p53-inducible gene Zmat3, encoding an RNA-binding protein, and we demonstrate that ZMAT3 is an important tumor suppressor downstream of p53 in mouse Kras^G12D-driven lung and liver cancers and human carcinomas. Integrative analysis of the ZMAT3 RNA-binding landscape and transcriptomic profiling reveals that ZMAT3 directly modulates exon inclusion in transcripts encoding proteins of diverse functions, including the p53 inhibitors MDM4 and MDM2, splicing regulators, and components of varied cellular processes. Interestingly, these exons are enriched in NMD signals, and, accordingly, ZMAT3 broadly affects target transcript stability. Collectively, these studies reveal ZMAT3 as a novel RNA-splicing and homeostasis regulator and a key component of p53-mediated tumor suppression.

Analysis of the autoimmune response against BP180 in patients with Alzheimer's disease

Background

Current epidemiological studies suggest a significant correlation between Alzheimer's disease (AD) and bullous pemphigoid (BP). However, the autoimmune response against BP180 in patients with AD has not been fully understood. investigated.

Methods

We randomly enrolled 48 patients with AD and 50 sex- and age-matched healthy controls. We detected the presence/absence and the level of anti-BP180/BP230 immunoglobulin G (IgG) autoantibodies in the patients' serum to determine whether said antibodies possess reactivity against the BP180 protein in the human brain and skin.

Results

The enzyme-linked immunosorbent assay (ELISA) results revealed that the positive rate of anti-BP180 autoantibodies in patients with AD (23/48, 47.9%) was significantly higher than that in controls (4/50, 8.0%; P<0.0001). These ELISA-positive patients were further examined through immunoblotting. Sera from nine patients with AD (9/23, 39.1%) and one control (1/4, 25.0%) reacted with human cutaneous recombinant full-length BP180 and BP180-noncollagenous 16A (NC16A). Sera from 11 (11/23, 47.8%) patients with AD reacted with a 180-kDa protein from the human brain extract, but none of the controls' sera recognized the corresponding protein band. The majority of the patients in the anti-BP180-positive AD group were men (14/23, 60.9%) who were older (74.0 years) compared with those in the control group (6/25, 24.0%; P<0.05) (72.2 years; P<0.01).

Conclusions

Anti-BP180 autoantibodies are present in AD and recognize human recombinant full-length BP180 and a 180-kDa protein from the human brain extract, suggesting that BP180 is a shared autoantigen in AD and BP and may help clarify the mechanism to explain why a high risk of BP exists in AD. Elderly male patients with AD are significantly more likely to develop BP180 serum autoreactivity compared with other patients with AD.

Bullous pemphigoid autoantibodies

<abstract> <p>Autoimmune blistering skin disorders are rare. According to direct immunofluorescence studies, three categories are described: pemphigus group, pemphigoid group and dermatitis herpetiformis. Among these diseases, bullous pemphigoid is the most common. Patients with typical bullous pemphigoid disease are usually elderly and have many comorbidities. Considering that topical and systemic corticosteroids are the first choice therapy, these patients also have increased morbidity and risk of death. The main characteristic of bullous pemphigoid as an acquired autoimmune blistering disease is the formation of autoantibodies against hemidesmosomal antigens BP180 and BP230. Although IgG autoantibodies predominate within the plasma and skin of BP patients, some features of the disease cannot be explained solely by IgG-mediated mechanisms. Epitope spreading phenomena, immunoglobulin class switch and the relevance of IgM and IgE autoantibodies are discussed in this article.</p> </abstract>

Composition of hemidesmosomes in basal keratinocytes of normal buccal mucosa and oral lichen planus

Oral lichen planus (OLP) is a chronic inflammatory disease displaying ultrastructural disturbances in epithelial hemidesmosomes. The expression of several key hemidesmosomal components in OLP as well as in normal buccal mucosa is, however, unknown. The aim of the study was therefore to examine intracellular and extracellular components involved in hemidesmosomal attachment, in OLP (n = 20) and in normal buccal mucosa (n = 10), by immunofluorescence. In normal buccal mucosa, laminin-α3γ2, integrin-α6β4, CD151, collagen α-1(XVII) chain, and dystonin showed linear expression along the basal membrane, indicating the presence of type I hemidesmosomes. Plectin stained most epithelial cell membranes and remained unphosphorylated at S4642. In OLP, most hemidesmosomal molecules examined showed disturbed expression consisting of discontinuous increases, apicolateral location, and/or intracellular accumulation. Plectin showed S4642-phosphorylation at the basement membrane, and deposits of laminin-α3 and laminin-γ2 were found within the connective tissue. The disturbed expression of hemidesmosomal proteins in OLP indicates deficient attachment of the basal cell layer, which can contribute to detachment and cell death of basal keratinocytes seen in the disease.

Parkinson's Disease and Its Dermatological Associations: Is Your Skin Whispering You a Diagnosis?

Parkinson's disease (PD) is a neurodegenerative disease characterized clinically by the triad of resting tremor, rigidity, and bradykinesia. Although PD is primarily known for motor disturbance, 98.6% of patients experience one or more non-motor symptoms at all stages of the disease. Dermatological disorders are discussed as common non-motor associations of PD since the 20th century. Many studies have shown that patients of PD are predisposed to skin disorders. This article is a traditional review done to analyze the association between PD and its dermatological manifestations. We did a literature search using six keywords in the PubMed database and took the relevant articles published in the last 10 years. We reviewed more than 100 articles, which also included animal studies. On meticulous review, we observed an increased incidence of certain skin disorders like seborrheic dermatitis, bullous pemphigoid, rosacea, and melanoma in patients of PD. These disorders share either common risk factors or underlying mechanisms revolving around genetics, immunology, inflammation, and pathophysiology of PD, but the exact causation yet seems obscured. We believe that this opens a horizon for more research in the link between the skin and nervous system. We also emphasize that the dermatologists, neurologists and general physicians should address the cutaneous disorders in PD timely, educate their patients, help them lessen the psychosocial distress, and improve their quality of life.

Neurological Cancer is a Risk Factor for Bullous Pemphigoid: 11-Year Population-Based Cohort Study

BACKGROUND

There is evidence suggesting an association between bullous pemphigoid (BP) and a range of neurological diseases. Whether neurological cancer is a risk factor for BP remains unknown.

OBJECTIVE

The aim of the study was to investigate the risk of subsequent BP among patients with neurological cancer.

METHODS

This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Research Database between 2000 and 2012. A total of 8313 patients with neurological cancer and 33,252 age-, sex-, and index-date-matched controls were recruited. The hazard ratio (HR) for subsequent BP in patients with neurological cancer was analyzed using a Cox model and Fine-Gray competing risk model, with mortality as the competing event.

RESULTS

The incidence rates of BP per 100,000 person-years were 37.2 for patients with neurological cancer and 6.8 for controls. The crude incidence rate ratio was 5.49 (95% confidence interval [CI] 2.18-13.30). The mean time to occurrence of BP was 4.48 ± 3.40 years for patients with neurological cancer. Neurological cancer (HR 9.65, 95% CI 3.76-24.77 for the Cox model; HR 2.41, 95% CI 1.14-5.14 for the competing risk model), age per year (HR 1.10, 95% CI 1.05-1.15 for the Cox model; HR 1.06, 95% CI 1.02-1.09 for the competing risk model), and dementia (HR 6.31, 95% CI 2.49-15.99 for the Cox model; HR 7.50, 95% CI 2.84-19.85 for the competing risk model) significantly increased the risk of BP.

CONCLUSIONS

Neurological cancer increased the risk for subsequent BP by 2.4-fold, with a relatively short gap of 4.5 years.

Novel Compound Heterozygous DST Variants Causing Hereditary Sensory and Autonomic Neuropathies VI in Twins of a Chinese Family

Background: Hereditary sensory and autonomic neuropathies (HSANs) are a rare and severe group of sensory axonal neuropathies. HSANs have been classified into eight groups based on mode of inheritance, clinical features, and the involved genes. HSAN-VI, perhaps the most notable type, is an autosomal recessive disease, which manifests as the severely impaired pain sensitivity, autonomic disturbances, distal myopathy, spontaneous or surgical amputations, and sometimes early death. Mutations in DST have been identified as the cause of HSAN-VI. DST encodes dystonin, a member of the plakin protein family that is involved in cytoskeletal filament networks. Dystonin has seven major isoforms in nerve, muscle, and epithelium.

Material and Methods: The present study investigated a Chinese family with HSAN and explored potential pathogenic variants using whole-exome sequencing (WES). Variants were screened and filtered through bioinformatics analysis and prediction of variant pathogenicity. Co-segregation analysis was subsequently conducted.

Results: We identified compound heterozygous variants of DST (c.3304G>A, p.V1102I and c.13796G>A, p.R4599H) in two patients.

Conclusion: We reported on a Chinese family with HSAN-VI family and detected the disease-causing variants. Our description expands the spectrum of known DST variants and contributes to the clinical diagnosis of HSAN-VI.

Diverse dystonin gene mutations cause distinct patterns of Dst isoform deficiency and phenotypic heterogeneity in Dystonia musculorum mice

Loss-of-function mutations in dystonin (DST) can cause hereditary sensory and autonomic neuropathy type 6 (HSAN-VI) or epidermolysis bullosa simplex (EBS). Recently, DST-related diseases were recognized to be more complex than previously thought because a patient exhibited both neurological and skin manifestations, whereas others display only one or the other. A single DST locus produces at least three major DST isoforms: DST-a (neuronal isoform), DST-b (muscular isoform) and DST-e (epithelial isoform). Dystonia musculorum (dt) mice, which have mutations in Dst, were originally identified as spontaneous mutants displaying neurological phenotypes. To reveal the mechanisms underlying the phenotypic heterogeneity of DST-related diseases, we investigated two mutant strains with different mutations: a spontaneous Dst mutant (Dstdt-23Rbrc mice) and a gene-trap mutant (DstGt mice). The Dstdt-23Rbrc allele possesses a nonsense mutation in an exon shared by all Dst isoforms. The DstGt allele is predicted to inactivate Dst-a and Dst-b isoforms but not Dst-e There was a decrease in the levels of Dst-a mRNA in the neural tissue of both Dstdt-23Rbrc and DstGt homozygotes. Loss of sensory and autonomic nerve ends in the skin was observed in both Dstdt-23Rbrc and DstGt mice at postnatal stages. In contrast, Dst-e mRNA expression was reduced in the skin of Dstdt-23Rbrc mice but not in DstGt mice. Expression levels of Dst proteins in neural and cutaneous tissues correlated with Dst mRNAs. Because Dst-e encodes a structural protein in hemidesmosomes (HDs), we performed transmission electron microscopy. Lack of inner plaques and loss of keratin filament invasions underneath the HDs were observed in the basal keratinocytes of Dstdt-23Rbrc mice but not in those of DstGt mice; thus, the distinct phenotype of the skin of Dstdt-23Rbrc mice could be because of failure of Dst-e expression. These results indicate that distinct mutations within the Dst locus can cause different loss-of-function patterns among Dst isoforms, which accounts for the heterogeneous neural and skin phenotypes in dt mice and DST-related diseases.

Human Regulatory T Cells From Umbilical Cord Blood Display Increased Repertoire Diversity and Lineage Stability Relative to Adult Peripheral Blood

The human T lymphocyte compartment is highly dynamic over the course of a lifetime. Of the many changes, perhaps most notable is the transition from a predominantly naïve T cell state at birth to the acquisition of antigen-experienced memory and effector subsets following environmental exposures. These phenotypic changes, including the induction of T cell exhaustion and senescence, have the potential to negatively impact efficacy of adoptive T cell therapies (ACT). When considering ACT with CD4+CD25+CD127-/lo regulatory T cells (Tregs) for the induction of immune tolerance, we previously reported ex vivo expanded umbilical cord blood (CB) Tregs remained more naïve, suppressed responder T cells equivalently, and exhibited a more diverse T cell receptor (TCR) repertoire compared to expanded adult peripheral blood (APB) Tregs. Herein, we hypothesized that upon further characterization, we would observe increased lineage heterogeneity and phenotypic diversity in APB Tregs that might negatively impact lineage stability, engraftment capacity, and the potential for Tregs to home to sites of tissue inflammation following ACT. We compared the phenotypic profiles of human Tregs isolated from CB versus the more traditional source, APB. We conducted analysis of fresh and ex vivo expanded Treg subsets at both the single cell (scRNA-seq and flow cytometry) and bulk (microarray and cytokine profiling) levels. Single cell transcriptional profiles of pre-expansion APB Tregs highlighted a cluster of cells that showed increased expression of genes associated with effector and pro-inflammatory phenotypes (CCL5, GZMK, CXCR3, LYAR, and NKG7) with low expression of Treg markers (FOXP3 and IKZF2). CB Tregs were more diverse in TCR repertoire and homogenous in phenotype, and contained fewer effector-like cells in contrast with APB Tregs. Interestingly, expression of canonical Treg markers, such as FOXP3, TIGIT, and IKZF2, were increased in CB CD4+CD127+ conventional T cells (Tconv) compared to APB Tconv, post-expansion, implying perinatal T cells may adopt a default regulatory program. Collectively, these data identify surface markers (namely CXCR3) that could be depleted to improve purity and stability of APB Tregs, and support the use of expanded CB Tregs as a potentially optimal ACT modality for the treatment of autoimmune and inflammatory diseases.

Role of BP230 autoantibodies in bullous pemphigoid

Bullous pemphigoid (BP) is an autoimmune disease associated with subepidermal blistering due to autoantibodies directed against BP180 and BP230. BP180 is currently considered as the major pathogenic autoantigen. However, previous clinical findings suggested that anti-BP230 autoantibodies alone can cause skin lesions in animal models and many BP patients. The characteristics of BP230 and the pathogenic roles of anti-BP230 antibodies have been proposed. First, at the molecular level, BP230 mediates the attachment of keratin intermediate filaments to the hemidesmosomal plaque and interacts with other constituents of hemidesmosomes. Second, the presence of BP230 autoantibodies may correlate with specific clinical features of BP. The immunoglobulin (Ig)G autoantibodies from BP patients react mainly against the C-terminus of BP230, while the IgE autoantibodies are still inconclusive. Third, in vivo, autoantibodies against BP230 involved in the disease may not only induce the inflammatory response but also impair the structural stability of hemidesmosomes. This article reviews recently published work about the role of BP230 and its antibodies, including IgG and IgE, aiming to find clues of its clinical association and lay the foundation for the research on the pathogenicity of antibodies against BP230.

HSAN-VI: A spectrum disorder based on dystonin isoform expression

Hereditary sensory and autonomic neuropathy (HSAN-VI) is a recessive genetic disorder that arises because of mutations in the human dystonin gene (DST, previously known as bullous pemphigoid antigen 1). Although initial characterization of HSAN-VI reported it as a sensory neuropathy that was lethal in infancy, we now know of a number of heterozygous mutations in DST that result in milder forms of the disease. Akin to what we observe in the mouse model dystonia musculorum (Dst^dt), we believe that the heterogeneity of HSAN-VI can be attributed to a number of dystonin isoforms that the mutation affects. Lack of neuronal isoform dystonin-a2 is likely the universal determinant of HSAN-VI because all reported human cases are null for this isoform, as are all Dst^dt mouse alleles. Compensatory mechanisms by intact dystonin-a isoforms also likely play a role in regulating disease severity, although we have yet to determine what specific effect dystonin-a1 and dystonin-a3 have on the pathogenesis of HSAN-VI.

The Intersection of IgE Autoantibodies and Eosinophilia in the Pathogenesis of Bullous Pemphigoid

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by autoantibodies targeting cellular adhesion molecules. While IgE autoantibodies are occasionally reported in other autoimmune blistering diseases, BP is unique in that most BP patients develop an IgE autoantibody response. It is not known why BP patients develop self-reactive IgE and the precise role of IgE in BP pathogenesis is not fully understood. However, clinical evidence suggests an association between elevated IgE antibodies and eosinophilia in BP patients. Since eosinophils are multipotent effector cells, capable cytotoxicity and immune modulation, the putative interaction between IgE and eosinophils is a primary focus in current studies aimed at understanding the key components of disease pathogenesis. In this review, we provide an overview of BP pathogenesis, highlighting clinical and experimental evidence supporting central roles for IgE and eosinophils as independent mediators of disease and via their interaction. Additionally, therapeutics targeting IgE, the Th2 axis, or eosinophils are also discussed.

Demographics and Autoantibody Profiles of Pemphigoid Patients with Underlying Neurologic Diseases

Bullous pemphigoid (BP) is an autoantibody-mediated blistering disease that is often associated with neurologic disease. BP antibodies target two epidermal adhesion molecules, known as BP180 and BP230. Homologues to these proteins are found in the brain, and it is hypothesized that neurologic disease leads to the production of autoantibodies that can cross-react with their cutaneous forms. To better understand the link between BP and neurologic disease, we evaluated primary demographic features (age, sex, race, ethnicity, and elapsed time between onset of skin symptoms and BP diagnosis), severity of BP, and IgG and IgE autoantibody levels in BP control individuals and patients with BP with preceding Parkinson disease, dementia, and stroke. The main findings of this study are that patients with BP with preceding neurologic disease have a shorter elapsed time between onset of skin disease and BP diagnosis and that patients with preceding Parkinson disease or dementia, but not stroke, are significantly older than patients with BP without neurologic disease. However, no significant differences in clinical presentation, BP severity scores, or autoantibody (IgG and IgE) responses were observed among the groups. These findings suggest that, despite the age difference, the clinical phenotype of BP is not affected by preceding neurologic disease.

Microtubule-Associated Proteins: Structuring the Cytoskeleton

Microtubule-associated proteins (MAPs) were initially discovered as proteins that bind to and stabilize microtubules. Today, an ever-growing number of MAPs reveals a more complex picture of these proteins as organizers of the microtubule cytoskeleton that have a large variety of functions. MAPs enable microtubules to participate in a plethora of cellular processes such as the assembly of mitotic and meiotic spindles, neuronal development, and the formation of the ciliary axoneme. Although some subgroups of MAPs have been exhaustively characterized, a strikingly large number of MAPs remain barely characterized other than their interactions with microtubules. We provide a comprehensive view on the currently known MAPs in mammals. We discuss their molecular mechanisms and functions, as well as their physiological role and links to pathologies.

Dystonin-A3 upregulation is responsible for maintenance of tubulin acetylation in a less severe dystonia musculorum mouse model for hereditary sensory and autonomic neuropathy type VI

Hereditary sensory and autonomic neuropathy type VI (HSAN-VI) is a recessive human disease that arises from mutations in the dystonin gene (DST; also known as Bullous pemphigoid antigen 1 gene). A milder form of HSAN-VI was recently described, resulting from loss of a single dystonin isoform (DST-A2). Similarly, mutations in the mouse dystonin gene (Dst) result in severe sensory neuropathy, dystonia musculorum (Dstdt). Two Dstdt alleles, Dstdt-Tg4 and Dstdt-27J, differ in the severity of disease. The less severe Dstdt-Tg4 mice have disrupted expression of Dst-A1 and -A2 isoforms, while the more severe Dstdt-27J allele affects Dst-A1, -A2 and -A3 isoforms. As dystonin is a cytoskeletal-linker protein, we evaluated microtubule network integrity within sensory neurons from Dstdt-Tg4 and Dstdt-27J mice. There is a significant reduction in tubulin acetylation in Dstdt-27J indicative of microtubule instability and severe microtubule disorganization within sensory axons. However, Dstdt-Tg4 mice have no change in tubulin acetylation, and microtubule organization was only mildly impaired. Thus, microtubule instability is not central to initiation of Dstdt pathogenesis, though it may contribute to disease severity. Maintenance of microtubule stability in Dstdt-Tg4 dorsal root ganglia could be attributed to an upregulation in Dst-A3 expression as a compensation for the absence of Dst-A1 and -A2 in Dstdt-Tg4 sensory neurons. Indeed, knockdown of Dst-A3 in these neurons resulted in a decrease in tubulin acetylation. These findings shed light on the possible compensatory role of dystonin isoforms within HSAN-VI, which might explain the heterogeneity in symptoms within the reported forms of the disease.

Neurological disorders are associated with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease with an increased incidence particularly among the elderly. Several studies have recently reported an association between BP and neurological disorders.

OBJECTIVE

To evaluate the association between BP and neurological disorders in a single centre in Germany.

METHODS

We retrospectively assessed 183 patients with BP (diagnosed between 2011 and 2015) and 348 age- and sex-matched controls for neurological disorders. The latter were confirmed either by a neurologist or psychiatrist.

RESULTS

Overall, there was a highly statistically significant association between BP and neurological disorders (P < 0.0001). These included dementia (P < 0.0001), Parkinson`s disease (P = 0.0434), stroke (P = 0.0015) and other neurological disorders but not Alzheimer's diseases, which was more common among patients in the control group.

CONCLUSION

Our cohort of bullous pemphigoid and neurological disorders demonstrates a significant association between bullous pemphigoid and neurological disorders, including dementia, Parkinson's disease and stroke. These observations support the need for future studies in order to elucidate the immunological mechanisms responsible for these comorbidities.

Anti-BP180 Autoantibodies Are Present in Stroke and Recognize Human Cutaneous BP180 and BP180-NC16A

Objective: Current evidence has revealed a significant association between bullous pemphigoid (BP) and neurological diseases (ND), including stroke, but the incidence of BP autoantibodies in patients with stroke has not previously been investigated. Our study aimed to assess BP antigen-specific antibodies in stroke patients. Design: One hundred patients with stroke and 100 matched healthy controls were randomly selected for measurement of anti-BP180/BP230 IgG autoantibodies by enzyme-linked immunosorbent assay (ELISA), salt-split indirect immunofluorescence (IIF), and immunoblotting against human cutaneous BP180 and BP180-NC16A. Results: Anti-BP180 autoantibodies were found in 14 (14.0%) patients with stroke and 5 (5.0%) of controls by ELISA (p < 0.05). Sera from 13 (13.0%) patients with stroke and 3 (3.0%) controls reacted with 180-kDa proteins from human epidermal extract (p < 0.05). 11 (11.0%) of stroke and 2 (2.0%) of control sera recognized the human recombinant full length BP180 and NC16A (p < 0.05). The anti-BP180-positive patients were significantly younger than the negative patients at the time of stroke (p < 0.001). Conclusion: Development of anti-BP180 autoantibodies occurs at a higher frequency after stroke, suggesting BP180 as a relatively common autoantigen after stroke and providing novel insights into BP pathogenesis in aging.

Mammalian Plakins, Giant Cytolinkers: Versatile Biological Functions and Roles in Cancer

Cancer is a highly lethal disease that is characterized by aberrant cell proliferation, migration, and adhesion, which are closely related to the dynamic changes of cytoskeletons and cytoskeletal-adhesion. These will further result in cell invasion and metastasis. Plakins are a family of giant cytolinkers that connect cytoskeletal elements with each other and to junctional complexes. With various isoforms composed of different domain structures, mammalian plakins are broadly expressed in numerous tissues. They play critical roles in many cellular processes, including cell proliferation, migration, adhesion, and signaling transduction. As these cellular processes are key steps in cancer development, mammalian plakins have in recent years attracted more and more attention for their potential roles in cancer. Current evidence shows the importance of mammalian plakins in various human cancers and demonstrates mammalian plakins as potential biomarkers for cancer. Here, we introduce the basic characteristics of mammalian plakins, review the recent advances in understanding their biological functions, and highlight their roles in human cancers, based on studies performed by us and others. This will provide researchers with a comprehensive understanding of mammalian plakins, new insights into the development of cancer, and novel targets for cancer diagnosis and therapy.

Advances in understanding the molecular basis of skin fragility

Skin fragility refers to a large group of conditions in which the ability of the skin to provide protection against trivial mechanical trauma is diminished, resulting in the formation of blisters, erosions, wounds, or scars. Acquired and physiological skin fragility is common; genetic disorders are rare but give insight into the molecular mechanisms ensuring skin stability. The paradigm is represented by inherited epidermolysis bullosa. This review is focused on recent advances in understanding the molecular basis of genetic skin fragility, including emerging concepts, controversies, unanswered questions, and opinions of the author. In spite of the advanced knowledge on the genetic causes of skin fragility, the molecular pathology is still expanding. Open questions in understanding the molecular basis of genetic skin fragility are the following: what are the causes of phenotypes which remain genetically unsolved, and what are the molecular modifiers which might explain phenotypic differences among individuals with similar mutations?  New mutational mechanisms and new genes have recently been discovered and are briefly described here. Comprehensive next-generation sequencing-based genetic testing improved mutation detection and facilitated the identification of the genetic basis of unclear and new phenotypes. Characterization of the biochemical and cell biological consequences of the genetic variants is challenging and laborious but may represent the basis for personalized therapeutic approaches. Molecular modifiers of skin fragility have been uncovered in particular animal and genetic models but not in larger cohorts of patients. This scientific progress is the basis for revisions of the epidermolysis bullosa classification and for innovative therapeutic approaches designed for this intractable condition.

The Association Between Frontotemporal Lobar Degeneration and Bullous Pemphigoid

Recent studies have shown an epidemiological and immunological association between bullous pemphigoid (BP) and several neurological or psychiatric diseases. Here, our aim was for the first time to specify whether an association exists between BP and frontotemporal lobar degeneration (FTLD). Medical histories of FTLD patients (N = 196) were screened for clinical comorbidity, and BP180 and BP230 autoantibodies were analyzed in the sera of FTLD patients (N = 70, including 24 C9orf72 repeat expansion carriers) by BP180-NC16A-ELISA and BP230-ELISA. One FTLD patient (C9orf72 repeat expansion carrier) had a comorbid diagnosis of BP. Increased levels of serum BP180 autoantibodies (cutoff value >9 U/ml) were detected more often in FTLD patients (10.0%) than in controls (4.9%). Moreover, elevated levels of both BP180 and BP230 autoantibodies were found more often in C9orf72 repeat expansion-carrying FTLD than non-carrying patients or controls. However, none of these differences reached a statistical significance likely due to our limited cohort size. In conclusion, our findings suggest that subset of FTLD patients especially with the C9orf72 repeat expansion may have an immunological association with BP.

Defenders and Challengers of Endothelial Barrier Function

Regulated vascular permeability is an essential feature of normal physiology and its dysfunction is associated with major human diseases ranging from cancer to inflammation and ischemic heart diseases. Integrity of endothelial cells also play a prominent role in the outcome of surgical procedures and organ transplant. Endothelial barrier function and integrity are regulated by a plethora of highly specialized transmembrane receptors, including claudin family proteins, occludin, junctional adhesion molecules (JAMs), vascular endothelial (VE)-cadherin, and the newly identified immunoglobulin (Ig) and proline-rich receptor-1 (IGPR-1) through various distinct mechanisms and signaling. On the other hand, vascular endothelial growth factor (VEGF) and its tyrosine kinase receptor, VEGF receptor-2, play a central role in the destabilization of endothelial barrier function. While claudins and occludin regulate cell-cell junction via recruitment of zonula occludens (ZO), cadherins via catenin proteins, and JAMs via ZO and afadin, IGPR-1 recruits bullous pemphigoid antigen 1 [also called dystonin (DST) and SH3 protein interacting with Nck90/WISH (SH3 protein interacting with Nck)]. Endothelial barrier function is moderated by the function of transmembrane receptors and signaling events that act to defend or destabilize it. Here, I highlight recent advances that have provided new insights into endothelial barrier function and mechanisms involved. Further investigation of these mechanisms could lead to the discovery of novel therapeutic targets for human diseases associated with endothelial dysfunction.

Structural proteins of the dermal-epidermal junction targeted by autoantibodies in pemphigoid diseases

The dermal-epidermal junction consists of a network of several interacting structural proteins that strengthen adhesion and mediate signalling events. This structural network consists of hemidesmosomal-anchoring filament complexes connecting the basal keratinocytes to the basement membrane. The anchoring filaments in turn interact with the anchoring fibrils to attach the basement membrane to the underlying dermis. Several of these structural proteins are recognized by autoantibodies in pemphigoid diseases, a heterogeneous group of clinically and immunopathologically diverse entities. Targeted proteins include the two intracellular plakins, plectin isoform 1a and BP230 (also called bullous pemphigoid antigen (BPAG) 1 isoform e (BPAG1e)). Plectin 1a and BP230 are connected to the intermediate filaments and to the cell surface receptor α6β4 integrin, which in turn is connected to laminin 332, a component of the anchoring filaments. Further essential adhesion proteins are BP180, a transmembrane protein, laminin γ1 and type VII collagen. Latter protein is the major constituent of the anchoring fibrils. Mutations in the corresponding genes of these adhesion molecules lead to inherited epidermolysis bullosa emphasizing the importance of these proteins for the integrity of the dermal-epidermal junction. This review will provide an overview on the structure and function of the proteins situated in the dermal-epidermal junction targeted by autoantibodies.

Neurological and psychiatric associations in bullous pemphigoid-more than skin deep?

In elderly patients, bullous pemphigoid (BP) is associated with several comorbidities; the strongest association occurs between BP and neurological diseases. Different types of dementia, Parkinson's disease, cerebrovascular disorders and epilepsy all have a significant association with BP, but patients with multiple sclerosis have the highest risk of BP. An existing neurological disorder appears to increase the risk for subsequent BP, but an increased risk for developing some neurological diseases has also been reported following BP diagnosis. BP seems to be associated with several psychiatric diseases such as schizophrenia, uni- and bipolar disorder, schizotypal and delusional disorders, and personality disorders, but the risk ratios are usually lower than with neurological diseases. In addition to the skin, the BP autoantigens BP180 and BP230 are expressed in the central nervous system. This finding together with the strong epidemiological association between neurological disorders and BP has led to an assumption that neurodegeneration or neuroinflammation could lead to a cross-reactive immunoresponse between neural and cutaneous antigens and the failure of self-tolerance. A subpopulation of patients with Alzheimer's disease or Parkinson's disease have circulating IgG autoantibodies against BP180, but currently their significance for the development of BP is unclear, because these antineural BP180 antibodies neither bind to the cutaneous basement membrane nor cause BP-like symptoms. Further studies analysing large and well-characterized populations of neurological and psychiatric patients are required to understand better the role of autoimmunization against neural BP autoantigens in the pathogenesis of BP.

Ocular features of multiple system atrophy

The aim of this paper is to gain better understanding of the ocular manifestations of multiple system atrophy (MSA), a neurodegenerative disorder rarely studied in terms of its ophthalmologic features. We performed a retrospective case series (1/1/05-12/31/14) to search for patients seen at Mayo Clinic, Rochester, MN, who had mention of MSA in the medical record and an eye examination, which yielded 285 cases. Of the 285, we identified 39 cases of true MSA. Each of these 39 patients was further reviewed for ocular abnormalities potentially related to MSA. Ocular findings potentially attributable to MSA were found in 64% of patients. Most common were dry eye (N = 14), conjugate eye movement abnormalities (N = 13), and ocular misalignment (N = 7). One patient had dry eye and monocular diplopia from trichiasis due to cicatricial pemphigoid, one had bilateral optic atrophy, and one had Adie's tonic pupil. Conjugate eye movement abnormalities (33%) and ocular misalignment (18%) were more common in patients with MSA-C. Patients with ocular findings, excluding dry eye, had a significantly shorter lifespan from time of initial neurologic symptoms to death. Our study confirms conjugate eye movement abnormalities and misalignment are common ocular findings in patients with MSA. Bilateral optic atrophy and cicatricial pemphigoid are possibly attributable to the disease. Ocular manifestations in MSA predict a poor prognosis as these patients have a significantly shorter lifespan. Therefore, we recommend patients with MSA have a comprehensive neuro-ophthalmologic exam at time of diagnosis, and thereafter, to screen for eye findings that may indicate a shorter lifespan.

Spectraplakin family proteins - cytoskeletal crosslinkers with versatile roles

The different cytoskeletal networks in a cell are responsible for many fundamental cellular processes. Current studies have shown that spectraplakins, cytoskeletal crosslinkers that combine features of both the spectrin and plakin families of crosslinkers, have a critical role in integrating these different cytoskeletal networks. Spectraplakin genes give rise to a variety of isoforms that have distinct functions. Importantly, all spectraplakin isoforms are uniquely able to associate with all three elements of the cytoskeleton, namely, F-actin, microtubules and intermediate filaments. In this Review, we will highlight recent studies that have unraveled their function in a wide range of different processes, from regulating cell adhesion in skin keratinocytes to neuronal cell migration. Taken together, this work has revealed a diverse and indispensable role for orchestrating the function of different cytoskeletal elements in vivo.

BPAG1 in muscles: Structure and function in skeletal, cardiac and smooth muscle

BPAG1, also known as Dystonin or BP230, belongs to the plakin family of proteins, which has multiple cytoskeleton-binding domains. Several BPAG1 isoforms are produced by a single BPAG1 genomic locus using different promoters and exons. For example, BPAG1a, BPAG1b, and BPAG1e are predominantly expressed in the nervous system, muscle, and skin, respectively. Among BPAG1 isoforms, BPAG1e is well studied because it was first identified as an autoantigen in patients with bullous pemphigoid, an autoimmune skin disease. BPAG1e is a component of hemidesmosomes, the adhesion complexes that promote dermal-epidermal cohesion. In the nervous system, the role of BPAG1a is also well studied because disruption of BPAG1a results in a phenotype identical to that of Dystonia musculorum (dt) mutants, which show progressive motor disorder. However, the expression and function of BPAG1 in muscles is not well studied. The aim of this review is to provide an overview of and highlight some recent findings on the expression and function of BPAG1 in muscles, which can assist future studies designed to delineate the role and regulation of BPAG1 in the dt mouse phenotype and in human hereditary sensory and autonomic neuropathy type 6 (HSAN6).