Updated mutational spectrum and genotype-phenotype correlations in ichthyosis patients with ABCA12 pathogenic variants.

Autosomal recessive congenital ichthyoses (ARCI) is a genetically heterogeneous condition that can be caused by pathogenic variants in at least 12 genes, including ABCA12. ARCI mainly consists of congenital ichthyosiform erythroderma (CIE), lamellar ichthyosis (LI) and harlequin ichthyosis (HI). The objective was to determine previously unreported pathogenic variants in ABCA12 and to update genotype-phenotype correlations for patients with pathogenic ABCA12 variants. Pathogenic variants in ABCA12 were detected using Sanger sequencing or a combination of Sanger sequencing and whole-exome sequencing. To verify the pathogenicity of a previously unreported large deletion and intron variant, cDNA analysis was performed using total RNA extracted from hair roots. Genetic analyses were performed on the patients with CIE, LI, HI and non-congenital ichthyosis with unusual phenotypes (NIUP), and 11 previously unreported ABCA12 variants were identified. Sequencing of cDNA confirmed the aberrant splicing of the variant ABCA12 in the patients with the previously unreported large deletion and intron variant. Our findings expand the phenotype spectrum of ichthyosis patients with ABCA12 pathogenic variants. The present missense variants in ABCA12 are considered to be heterogenous in pathogenicity, and they lead to varying disease severities in patients with ARCI and non-congenital ichthyosis with unusual phenotypes (NIUP).

Fusion with type 2 macrophages induces melanoma cell heterogeneity that potentiates immunological escape from cytotoxic T lymphocytes.

Evasion from immunity is a major obstacle to the achievement of successful cancer immunotherapy. Hybrids derived from cell-cell fusion are theoretically associated with tumor heterogeneity and progression by conferring novel properties on tumor cells, including drug resistance and metastatic capacity; however, their impact on immune evasion remains unknown. Here, we investigated the potency of tumor-macrophage hybrids in immune evasion. Hybrids were established by co-culture of a melanoma cell line (A375 cells) and type 2 macrophages. The hybrids showed greater migration ability and greater tumorigenicity than the parental melanoma cells. The hybrids showed heterogeneous sensitivity to New York esophageal squamous cell carcinoma-1 (NY-ESO-1)-specific T-cell receptor-transduced T (TCR-T) cells and two out of four hybrid clones showed less sensitivity to TCR-T compared with the parental cells. An in vitro tumor heterogeneity model revealed that the TCR-T cells preferentially killed the parental cells compared with the hybrids and the survival rate of the hybrids was higher than that of the parental cells, indicating that the hybrids evade killing by TCR-T cells efficiently. Analysis of a single-cell RNA sequencing dataset of patients with melanoma revealed that a few macrophages expressed RNA encoding melanoma differentiation antigens including melan A, tyrosinase, and premelanosome protein, which indicated the presence of hybrids in primary melanoma. In addition, the number of potential hybrids was correlated with a poorer response to immune checkpoint blockade. These results provide evidence that melanoma-macrophage fusion has a role in tumor heterogeneity and immune evasion. © 2023 The Pathological Society of Great Britain and Ireland.

Inclusion bodies are not uncommon in angioleiomyoma.

BACKGROUND: Leiomyomas with eosinophilic intracytoplasmic inclusion bodies have been described in the urinary bladder, brain, gastrointestinal tract, uterus, and oral cavity but not in the skin. Prompted by our recent experience with a case of cutaneous angioleiomyoma with many inclusion bodies, we hypothesized that similar cases might have been previously overlooked. METHODS: We retrospectively reviewed 30 cases of angioleiomyoma and 10 cases of piloleiomyoma focusing on inclusion bodies. RESULTS: More than 18 inclusion bodies per 250 µm squared were detected in five cases of angioleiomyoma, fewer than 11 bodies in 20 cases, and none in five cases. For the case with numerous inclusion bodies throughout the specimen, special staining was needed to make a diagnosis. No inclusion bodies were found in the piloleiomyomas. CONCLUSION: Inclusion bodies are relatively common in angioleiomyomas and can occasionally be numerous. They may serve as a point of distinction from piloleiomyomas. Because the presence of multiple eosinophilic intracytoplasmic inclusions can result in a rhabdoid appearance and make diagnosis challenging, we should be aware of this feature in angioleiomyomas.

Aluminum Chloride-Induced Apoptosis Leads to Keratinization Arrest and Granular Parakeratosis.

Aluminum chloride (AlCl3) is the main active ingredient in commonly used antiperspirant. Antiperspirant use may cause a rare keratinization disease, granular parakeratosis (GP), then AlCl3 may be associated with the etiology of GP. The objective of this study is to elucidate the skin effect of topical aluminum application using a mouse model. We sprayed 20% aluminum chloride every day on the depilated mice skin and analyzed the skin clinically, histopathologically, and immunohistologically. We have succeeded in the histological replication of GP on mouse skin. The basophilic granules in the stratum corneum contained filaggrin, and processing of profilaggrin to filaggrin was disrupted in aluminum-treated mouse skin (Al-mouse). In Al-mouse, cytochrome c and cleaved-caspase 3 were upregulated mainly in the granular layer, and caspase 3 p20 subunit was upregulated. TUNEL-positive cells increased significantly in the Al-mouse from the granular to the horny layer. Caspase 3 inhibitor inhibited granular parakeratotic change of Al-mouse. Our results indicated that aluminum-induced apoptosis leads to keratinization arrest and acceleration of nuclear degradation before completion of profilaggrin processing. This could lead to retention of the basophilic granules composed of underprocessed profilaggrin in the horny layer of Al-mouse skin, the hallmark of GP.

[Initial Experiences of Dynamic Sentinel Lymph Node Biopsy (DSNB) in Patients with Penile Cancer].

We present 2 cases of penile cancer in which the inguinal lymph node was not palpable and inguinal lymph node dissection (ILND) could be safely avoided by conducting dynamic sentinel lymph node biopsy (DSNB). The first case was in a 54-year-old man complaining of penile tumor for at least 3 months. We performed partial penectomy and DSNB. The pathological diagnosis was squamous cell carcinoma (SCC), pT2-3. There was no cancer metastasis in sentinel nodes (0/2). There has been no recurrence for 6 years after operation. The second case was 65-year-old man suffering from penile tumor for at least 6 months. We performed partial penectomy and DSNB. The pathological diagnosis was SCC,pT2. There was no cancer metastasis in sentinel nodes (0/3). There has been no recurrence for 1 year after operation. ILND has been recommended for intermediate and high-risk penile cancer even in patients with non-palpable inguinal lymph nodes. However,the complication of ILND is very high. DSNB has the potential to avoid ILND if there is no cancer metastasis in sentinel nodes.

Molecular basis of the skin barrier structures revealed by electron microscopy.

The barrier function of skin is indispensable for terrestrial animals. This function is mainly carried out by the epidermis, more specifically by its granular and cornified layers. The major structural components associated with this function are the intercellular lipid layer, desmosomes, corneodesmosomes, tight junctions, cornified cell envelope and keratin filaments. In this review, we discuss the current knowledge of their ultrastructure, their molecular basis and their relevance to skin disease.

Intracytoplasmic eosinophilic inclusion bodies with embryonic folliculosebaceous-apocrine unit differentiation in syringocystadenoma papilliferum.

We describe a case of syringocystadenoma papilliferum (SCAP) with a unique histopathology. A 50-year-old Japanese woman presented with a pedunculated tumor in the pubic region. Histopathological examination showed that the tumor was composed of basaloid cell proliferation interconnecting from the epidermis to the dermis. Ductal structures in the tumor were lined by club-shaped columnar cells with apical snouts. Interestingly, numerous vacuolated cells with hyaline globule-like cytoplasmic inclusions were present among the columnar cells, the content of which was identified as sialomucin. Electron microscopy revealed that the vacuolated cytosol of luminal cells represented intracytoplasmic lumens with a structure similar to embryonic apocrine ducts. We assumed that this case represents a rare variant of SCAP that had differentiated toward the embryonic folliculosebaceous-apocrine unit.

Histopathological Findings and Increased D-Dimer Are Predictive Factors of Systemic Thromboses in Eosinophilic Granulomatosis With Polyangiitis.

Eosinophilic granulomatosis with polyangiitis (EGPA; ie, Churg-Strauss syndrome) is one of the antineutrophil cytoplasmic antibody-associated vasculitis syndromes. Although extravascular granulomatoses are a well-known histopathological feature, the diverse histopathologic spectrum of cutaneous lesions has not been described in detail. Thus, this study sought to investigate the possible correlation between the clinical features and histopathology of cutaneous lesions in EGPA cases, focusing on systemic thrombogenic conditions, such as visceral infarction and deep vein thrombosis. Fourteen cases of EGPA diagnosed at the Department of Dermatology in Asahikawa Medical University from 1977 to 2017 were clinically and histopathologically reviewed. In 6 (43%) cases, skin lesions were the initial manifestation of EGPA. Among the cutaneous lesions, purpura and erythema were the most common. Persistent proteinuria and macrohematuria were observed in only 2 myeloperoxidase-antineutrophil cytoplasmic antibody-positive cases. Systemic thrombotic symptoms, such as cerebral infarction and deep vein thrombosis, were detected in 5 (36%) cases, and, in 3 of those cases, thromboses in dermal or subcutaneous vessels were observed histopathologically. Elevation of plasma D-dimer level (>2.5 µg/mL) was significantly correlated with concomitant systemic thrombotic symptoms (P = 0.0152, Fischer exact test). The histopathological finding of thrombotic features and increased plasma D-dimer were predictive factors of EGPA accompanied with systemic thromboses, such as deep vein thromboses and cerebral infarction.

Intratumoral injection of IFN-ß induces chemokine production in melanoma and augments the therapeutic efficacy of anti-PD-L1 mAb.

Despite recent advances in treatment for melanoma patients through using immune checkpoint inhibitors, these monotherapies have limitations and additional treatments have been explored. Type I IFNs have been used to treat melanoma and possess immunomodulatory effects including enhancement of T-cell infiltration. T-cell plays a critical role in immune checkpoint therapies via restoration of effector functions and tumor infiltration by T-cells predicts longer survival in a variety of cancer types. Moreover, tumor-infiltrating T-cells are associated with the expression of chemokines such as CCL5 and CXCR3 ligands in tumor tissues. We therefore investigated whether intratumoral injection of IFN-ß induces the expression of CCL5 and CXCR3 ligands in melanoma cells and has additional antitumor effects when combined with anti-PD-L1 mAb treatment. IFN-ß treatment enhanced CD8+ T-cell infiltration into tumors and CCL5 and CXCR3 ligand expression. In vivo studies using a mouse model showed that monotherapy with IFN-ß, but not with anti-PD-L1 mAb, inhibited tumor growth in comparison to control. However, the therapeutic efficacy of IFN-ß was significantly enhanced by the addition of anti-PD-L1 mAb. This antitumor response of combination therapy was abrogated by anti-CD8 mAb and IFN-ß augmented the neoantigen-specific T-cell response of anti-PD-L1 mAb. Our findings suggest that IFN-ß induces the expression of CCL5 and CXCR3 ligands in melanoma, which could play a role in T-cell recruitment, and enhances the efficacy of anti-PD-L1 mAb treatment in a CD8-dependent manner.

SVEP1 plays a crucial role in epidermal differentiation.

SVEP1 is a recently identified multidomain cell adhesion protein, homologous to the mouse polydom protein, which has been shown to mediate cell-cell adhesion in an integrin-dependent manner in osteogenic cells. In this study, we characterized SVEP1 function in the epidermis. SVEP1 was found by qRT-PCR to be ubiquitously expressed in human tissues, including the skin. Confocal microscopy revealed that SVEP1 is normally mostly expressed in the cytoplasm of basal and suprabasal epidermal cells. Downregulation of SVEP1 expression in primary keratinocytes resulted in decreased expression of major epidermal differentiation markers. Similarly, SVEP1 downregulation was associated with disturbed differentiation and marked epidermal acanthosis in three-dimensional skin equivalents. In contrast, the dispase assay failed to demonstrate significant differences in adhesion between keratinocytes expressing normal vs low levels of SVEP1. Homozygous Svep1 knockout mice were embryonic lethal. Thus, to assess the importance of SVEP1 for normal skin homoeostasis in vivo, we downregulated SVEP1 in zebrafish embryos with a Svep1-specific splice morpholino. Scanning electron microscopy revealed a rugged epidermis with perturbed microridge formation in the centre of the keratinocytes of morphant larvae. Transmission electron microscopy analysis demonstrated abnormal epidermal cell-cell adhesion with disadhesion between cells in Svep1-deficient morphant larvae compared to controls. In summary, our results indicate that SVEP1 plays a critical role during epidermal differentiation.

iRHOM2-dependent regulation of ADAM17 in cutaneous disease and epidermal barrier function.

iRHOM2 is a highly conserved, catalytically inactive member of the Rhomboid family, which has recently been shown to regulate the maturation of the multi-substrate ectodomain sheddase enzyme ADAM17 (TACE) in macrophages. Dominant iRHOM2 mutations are the cause of the inherited cutaneous and oesophageal cancer-susceptibility syndrome tylosis with oesophageal cancer (TOC), suggesting a role for this protein in epithelial cells. Here, using tissues derived from TOC patients, we demonstrate that TOC-associated mutations in iRHOM2 cause an increase in the maturation and activity of ADAM17 in epidermal keratinocytes, resulting in significantly upregulated shedding of ADAM17 substrates, including EGF-family growth factors and pro-inflammatory cytokines. This activity is accompanied by increased EGFR activity, increased desmosome processing and the presence of immature epidermal desmosomes, upregulated epidermal transglutaminase activity and heightened resistance to Staphylococcal infection in TOC keratinocytes. Many of these features are consistent with the presence of a constitutive wound-healing-like phenotype in TOC epidermis, which may shed light on a novel pathway in skin repair, regeneration and inflammation.

Cole Disease Results from Mutations in ENPP1.

The coexistence of abnormal keratinization and aberrant pigmentation in a number of cornification disorders has long suggested a mechanistic link between these two processes. Here, we deciphered the genetic basis of Cole disease, a rare autosomal-dominant genodermatosis featuring punctate keratoderma, patchy hypopigmentation, and uncommonly, cutaneous calcifications. Using a combination of exome and direct sequencing, we showed complete cosegregation of the disease phenotype with three heterozygous ENPP1 mutations in three unrelated families. All mutations were found to affect cysteine residues in the somatomedin-B-like 2 (SMB2) domain in the encoded protein, which has been implicated in insulin signaling. ENPP1 encodes ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), which is responsible for the generation of inorganic pyrophosphate, a natural inhibitor of mineralization. Previously, biallelic mutations in ENPP1 were shown to underlie a number of recessive conditions characterized by ectopic calcification, thus providing evidence of profound phenotypic heterogeneity in ENPP1-associated genetic diseases.

Short stature, onychodysplasia, facial dysmorphism, and hypotrichosis syndrome is caused by a POC1A mutation.

Disproportionate short stature refers to a heterogeneous group of hereditary disorders that are classified according to their mode of inheritance, clinical skeletal and nonskeletal manifestations, and radiological characteristics. In the present study, we report on an autosomal-recessive osteocutaneous disorder that we termed SOFT (short stature, onychodysplasia, facial dysmorphism, and hypotrichosis) syndrome. We employed homozygosity mapping to locate the disease-causing mutation to region 3p21.1-3p21.31. Using whole-exome-sequencing analysis complemented with Sanger direct sequencing of poorly covered regions, we identified a homozygous point mutation (c.512T>C [p.Leu171Pro]) in POC1A (centriolar protein homolog A). This mutation was found to cosegregate with the disease phenotype in two families. The p.Leu171Pro substitution affects a highly conserved amino acid residue and is predicted to interfere with protein function. Poc1, a POC1A ortholog, was previously found to have a role in centrosome stability in unicellular organisms. Accordingly, although centrosome structure was preserved, the number of centrosomes and their distribution were abnormal in affected cells. In addition, the Golgi apparatus presented a dispersed morphology, cholera-toxin trafficking from the plasma membrane to the Golgi was aberrant, and large vesicles accumulated in the cytosol. Collectively, our data underscore the importance of POC1A for proper bone, hair, and nail formation and highlight the importance of normal centrosomes in Golgi assembly and trafficking from the plasma membrane to the Golgi apparatus.

The biology and regulation of corneodesmosomes.

The stratum corneum of the epidermis is composed of stacked dead corneocytes embedded in lipid layers and is the main protective shield of the skin. The thickness of the stratum corneum is maintained fairly constantly through the balance between new cell creation and old cell removal. Corneodesmosomes are the main intercellular adhesive structures in the stratum corneum. They are transformed from desmosomes at the most superficial layer of the stratum granulosum of the epidermis. The major compositional distinction from desmosomes is the presence of corneodesmosin in the extracellular portion. Furthermore, corneodesmosomes are structurally different from desmosomes in that (1) they do not have a tri-lamellar desmoglea but rather one that is homogeneously electron-dense and (2) attachment plaques are integrated into a part of the cornified cell envelopes. When the extracellular regions of corneodesmosomes are fully degraded, desquamation occurs. The degradation process of corneodesmosomes is carefully controlled by a number of proteases and their inhibitors. The most important proteases involved in this process are the kallikrein-related peptidases. Their main inhibitor is the lympho-epithelial Kazal-type related inhibitor. Other regulators of this process include matriptase, meprin and mesotrypsin.

Inflammatory peeling skin syndrome caused by homozygous genomic deletion in the PSORS1 region encompassing the CDSN gene.

Peeling skin syndrome (PSS) type B is a rare recessive genodermatosis characterized by lifelong widespread, reddish peeling of the skin with pruritus. The disease is caused by small-scale mutations in the Corneodesmosin gene (CDSN) leading to premature termination codons. We report for the first time a Japanese case resulting from complete deletion of CDSN. Corneodesmosin was undetectable in the epidermis, and CDSN was unamplifiable by PCR. QMPSF analysis demonstrated deletion of CDSN exons inherited from each parent. Deletion mapping using microsatellite haplotyping, CGH array and PCR analysis established that the genomic deletion spanned 49-72 kb between HCG22 and TCF19, removing CDSN as well as five other genes within the psoriasis susceptibility region 1 (PSORS1) on 6p21.33. This observation widens the spectrum of molecular defects underlying PSS type B and shows that loss of these five genes from the PSORS1 region does not result in an additional cutaneous phenotype.

A homozygous nonsense mutation in the gene for Tmem79, a component for the lamellar granule secretory system, produces spontaneous eczema in an experimental model of atopic dermatitis.

BACKGROUND: Flaky tail (ma/ma Flg(ft/ft)) mice have a frameshift mutation in the filaggrin (Flg(ft)) gene and are widely used as a model of human atopic dermatitis associated with FLG mutations. These mice possess another recessive hair mutation, matted (ma), and develop spontaneous dermatitis under specific pathogen-free conditions, whereas genetically engineered Flg(-/-) mice do not. OBJECTIVE: We identified and characterized the gene responsible for the matted hair and dermatitis phenotype in flaky tail mice. METHODS: We narrowed down the responsible region by backcrossing ma/ma mice with wild-type mice and identified the mutation using next-generation DNA sequencing. We attempted to rescue the matted phenotype by introducing the wild-type matted transgene. We characterized the responsible gene product by using whole-mount immunostaining of epidermal sheets. RESULTS: We demonstrated that ma, but not Flg(ft), was responsible for the dermatitis phenotype and corresponded to a Tmem79 gene nonsense mutation (c.840C>G, p.Y280*), which encoded a 5-transmembrane protein. Exogenous Tmem79 expression rescued the matted hair and dermatitis phenotype of Tmem79(ma/ma) mice. Tmem79 was mainly expressed in the trans-Golgi network in stratum granulosum cells in the epidermis in both mice and humans. The Tmem79(ma/ma) mutation impaired the lamellar granule secretory system, which resulted in altered stratum corneum formation and a subsequent spontaneous dermatitis phenotype. CONCLUSIONS: The Tmem79(ma/ma) mutation is responsible for the spontaneous dermatitis phenotype in matted mice, probably as a result of impaired lamellar granule secretory system and altered stratum corneum barrier function.