A novel splice-site mutation in the ATP2C1 gene of a Chinese family with Hailey-Hailey disease

Identification of novel compound heterozygous variants in the DNAH1 gene of a Chinese family with left-right asymmetry disorder

Most internal organs in humans and other vertebrates exhibit striking left-right asymmetry in position and structure. Variation of normal organ positioning results in left-right asymmetry disorders and presents as internal organ reversal or randomization. Up to date, at least 82 genes have been identified as the causative genetic factors of left-right asymmetry disorders. This study sought to discover potential pathogenic variants responsible for left-right asymmetry disorder present in a Han-Chinese family using whole exome sequencing combined with Sanger sequencing. Novel compound heterozygous variants, c.5690A>G (p.Asn1897Ser) and c.7759G>A (p.Val2587Met), in the dynein axonemal heavy chain 1 gene (DNAH1), were found in the proband and absent in unaffected family members. Conservation analysis has shown that the variants affect evolutionarily conserved residues, which may impact the tertiary structure of the DNAH1 protein. The novel compound heterozygous variants may potentially bear responsibility for left-right asymmetry disorder, which results from a perturbation of left-right axis coordination at the earliest embryonic development stages. This study broadens the variant spectrum of left-right asymmetry disorders and may be helpful for genetic counseling and healthcare management for the diagnosed individual, and promotes a greater understanding of the pathophysiology.

The Pathogenic Mechanism of the ATP2C1 p.Ala109_Gln120del Mutation in Hailey-Hailey Disease

Background

Hailey-Hailey disease (HHD) is an autosomal dominant cutaneous disorder that manifests as repeated blisters and erosions on flexural or intertriginous skin areas. The calcium-transporting ATPase type 2C member 1 gene (ATP2C1) encodes the secretory pathway Ca²⁺/Mn²⁺-ATPase 1 (SPCA1), whose deficiency is responsible for HHD. An ATP2C1 splice-site mutation (c.325-2A>G, p.Ala109_Gln120del) was previously identified in a Han Chinese family with HHD.

Methods

In this study, the identified ATP2C1 splice-site mutation (c.325-2A>G, p.Ala109_Gln120del) was investigated in transfected human embryonic kidney 293 cells to analyze its pathogenic mechanism in HHD patients by using cycloheximide chase assay, CCK8 assay and in silico modeling of SPCA1 mutant.

Results

Cycloheximide chase assay showed that the degradation rate of the SPCA1 mutant was not obviously faster than that of the normal SPCA1. CCK8 assay showed that cell proliferation rates in the wild-type, A109_Q120del, and empty vector control groups all decreased in the gradient Mn²⁺ solutions in a dose-dependent manner. The cell proliferation rate in the wild-type was lower than that in the A109_Q120del and empty vector control (both P < 0.01), indicating overexpression of normal SPCA1 may rather induce Golgi stress, and even cell death. The cell proliferation rate in the A109_Q120del was lower than that in the empty vector control (P < 0.01), indicating that overexpression of the mutated SPCA1 may decrease its detoxification capability. Three-dimensional (3D) structure model of SPCA1 built by SWISS-MODEL and PyMOL showed that absence of the 12 amino acids from p.Ala109 to p.Gln120 in the SPCA1 mutant can cause obviously shortened transmembrane 2, which may affect correct localization of SPCA1 on the Golgi.

Conclusion

These results demonstrate that the ATP2C1 mutation (c.325-2A>G, p.Ala109_Gln120del) may cause impaired SPCA1 capability to detoxify Mn²⁺ and abnormal SPCA1 structure, which reveals a new side for the pathogenesis of HHD.

BMSC-Derived Exosomal Egr2 Ameliorates Ischemic Stroke by Directly Upregulating SIRT6 to Suppress Notch Signaling

Exosomes generated by BMSCs contribute to functional recovery in ischemic stroke. However, the regulatory mechanism is largely unknown. Exosomes were isolated from BMSCs. Tube formation, MTT, TUNEL, and flow cytometry assays were applied to examine cell angiogenesis, viability, and apoptosis. Protein and DNA interaction was evaluated by ChIP and luciferase assays. LDH release into the culture medium was examined. Infarction area was evaluated by TTC staining. Immunofluorescence staining was applied to examine CD31 expression. A mouse model of MCAO/R was established. BMSC-derived exosomes attenuated neuronal cell damage and facilitated angiogenesis of brain endothelial cells in response to OGD/R, but these effects were abolished by the knockdown of Egr2. Egr2 directly bound to the promoter of SIRT6 to promote its expression. The incompetency of Egr2-silencing exosomes was reversed by overexpression of SIRT6. Furthermore, SIRT6 inhibited Notch signaling via suppressing Notch1. Overexpression of SIRT6 and inhibition of Notch signaling improved cell injury and angiogenesis in OGD/R-treated cells. BMSC-derived exosomal Egr2 ameliorated MCAO/R-induced brain damage via upregulating SIRT6 to suppress Notch signaling in mice. BMSC-derived exosomes ameliorate OGD/R-induced injury and MCAO/R-caused cerebral damage in mice by delivering Egr2 to promote SIRT6 expression and subsequently suppress Notch signaling. Our study provides a potential exosome-based therapy for ischemic stroke.

LncRNA THRIL promotes high glucose-induced proliferation and migration of human retina microvascular endothelial cells through enhancing autophagy

AIMS

Diabetes retinopathy (DR) is associated with retinal microvascular system injury induced by high glucose (HG). This study aims to explore the role and mechanism of long non-coding RNA THRIL in regulating cell proliferation and migration of human retina microvascular endothelial cells (hRMECs) under HG condition.

METHOD

The gene and protein expression were detetced by RT-PCR and western blot, respectively. Cell proliferation and migration of hRMECs were examined using MTT assay and Transwell assay, respectively. The interaction between miR-125b-5p and THRIL or autophagy-related gene 4D (ATG4D) was analyzed using luciferase activity assay.

RESULTS

THRIL expression was induced by HG in hRMECs. THRIL overexpression enhanced the proliferation and migration of hRMECs induced by HG, whereas THRIL silencing yielded the opposite results. Furthermore, THRIL overexpression induced autophagy activation, and inhibition of autophagy by 3-methyladenine abrogated the promotory effects of THRIL overexpression on cell proliferation and migration of hRMECs. Mechanismly, THRIL inhibited miR-125b-5p to upregulate the expression of ATG4D (an important autophagy-related gene), thereby promoting autophagy. Moreover, miR-125b-5p overexpression or ATG4D silencing alone abolished the promoting effects of THRIL overexpression on HG-induced autophagy, proliferation and migration of hRMECs.

CONCLUSIONS

THRIL promotes HG-induced cell proliferation and migration of hRMECs through activation of autophagy via the miR-125b-5p/ATG4D axis. THRIL may serve as a potential therapeutic target for DR.

Extracellular Vesicle Application as a Novel Therapeutic Strategy for Ischemic Stroke

Ischemic stroke (IS) accounts for most of the cases of stroke onset, and due to short therapeutic time window for thrombolysis and numerous limited treatment measures and contraindications, lots of patients cannot receive satisfying therapeutic effects resulting in high disability and mortality worldly. In recent years, extracellular vesicles (EVs), as nanosized membrane-structured vesicles secreted from almost all cells, especially from stem/progenitor cells, have been reported to exert significant beneficial effects on IS from multiple approaches and notably ameliorate neurological outcome. Moreover, based on nano-size and lipid bilayer structure, EVs can easily penetrate the blood-brain barrier and migrate into the brain. In this review, we mainly systematically summarize the therapeutic effects of EVs on IS and explore their potential applications. Simultaneously, we also discuss administration routines, dosages, experimental observation time, and some key issues of EV application during IS treatment. It contributes to a comprehensive understanding of the progress of EV treatment for IS and providing confident evidence for further EV clinical application widely.

Two Novel Variants and One Previously Reported Variant in the ATP2C1 Gene in Chinese Hailey-Hailey Disease Patients

Hailey-Hailey disease (HHD) is a rare autosomal dominant genodermatosis. It is characterized clinically by recurrent erosions, blisters and erythematous plaques at the sites of friction and intertriginous areas. The pathogenic gene of HHD was reported to be the ATPase calcium-transporting type 2C member 1 gene (ATP2C1). In this study, genomic DNA polymerase chain reaction (PCR) and direct sequencing of ATP2C1 were performed from 3 Chinese pedigrees and 4 sporadic cases of HHD. We detected 3 heterozygous mutations, including 2 novel mutations (c.1673_1674insGTTG and c.2225A>G) and 1 recurrent nonsense mutation (c.1402C>T; NM_014382.4). The ATP2C1 gene was also screened in the asymptomatic members of pedigrees. Our results would further expand the mutation spectrum of the ATP2C1 gene and be helpful in the genetic counseling of patients with HHD.

Novel and recurrent variants of ATP2C1 identified in patients with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is a rare, late-onset autosomal dominant genodermatosis characterized by blisters, vesicular lesions, crusted erosions, and erythematous scaly plaques predominantly in intertriginous regions. HHD is caused by ATP2C1 mutations. About 180 distinct mutations have been identified so far; however, data of only few cases from Central Europe are available. The aim was to analyze the ATP2C1 gene in a cohort of Polish HHD patients. A group of 18 patients was enrolled in the study based on specific clinical symptoms. Mutations were detected using Sanger or next generation sequencing. In silico analysis was performed by prediction algorisms and dynamic structural modeling. In two cases, mRNA analysis was performed to confirm aberrant splicing. We detected 13 different mutations, including 8 novel, 2 recurrent (p.Gly850Ter and c.325-3 T > G), and 6 sporadic (c.423-1G > T, c.899 + 1G > A, p.Leu539Pro, p.Thr808TyrfsTer16, p.Gln855Arg and a complex allele: c.[1610C > G;1741 + 3A > G]). In silico analysis shows that all novel missense variants are pathogenic or likely pathogenic. We confirmed pathogenic status for two novel variants c.325-3 T > G and c.[1610C > G;1741 + 3A > G] by mRNA analysis. Our results broaden the knowledge about genetic heterogeneity in Central European patients with ATP2C1 mutations and also give further evidence that careful and multifactorial evaluation of variant pathogenicity status is essential.

Review of 52 cases with Hailey-Hailey disease identified 25 novel mutations in Chinese Han population

Hailey-Hailey disease (HHD) is a rare autosomal dominant inherited keratosis caused by mutations in ATP2C1. The aim of our study was to identify and analyze the features of the mutations in HHD. We examined 52 Chinese Han cases which were diagnosed as HHD based on their clinical and histological findings. Genomic DNA polymerase chain reaction and direct sequencing of ATP2C1 were performed from peripheral blood samples of the patients and 100 unrelated healthy controls. Twenty-five novel mutations and 14 recurrent mutations were identified, including 11 (28.2%) missense mutations, nine (23.1%) frame-shift deletion mutations, eight (20.5%) nonsense mutations, seven (17.9%) splicing mutations and four (10.3%) frame-shift insertion mutations. Together with ours, all 209 mutations showed a uniform distribution without hotspots or clusters. In addition, there is no specific genotype-phenotype correlation in HHD. Our findings update the spectrum of mutations in ATP2C1.