Establishment of a Mouse Model for Porokeratosis Due to Mevalonate Diphosphate Decarboxylase Deficiency.

INTRODUCTION: Porokeratosis (PK) is an autoinflammatory keratinization disease (AIKD) characterized by circular or annular skin lesions with a hyperkeratotic rim, pathologically shown as the cornoid lamella. Four genes that cause PK are associated with the mevalonate (MV) pathway. In Chinese PK patients, mevalonate diphosphate decarboxylase (MVD) is the most common causative gene. The lack of an animal model has greatly limited research on PK pathogenesis. MATERIALS AND METHODS: In this research, we constructed K14-CreERT2-Mvdfl/fl mice using the Cre-LoxP system to create a mouse model for in-depth studies of PK. The Epidermal Mvd gene was knocked out by intraperitoneal injection of Tamoxifen (TAM). Pathology, immunohistochemistry, RNA-seq, and Western Blot analysis were performed. RESULTS: Skin lesions appeared following Mvd deficiency, and pathological examination revealed the characteristic cornoid lamella, as well as cutaneous inflammation. Furthermore, we observed elevated levels of IL-17A and IL-1ß, and a decreased Loricrin level in epidermal Mvd-deficient mice. Compared with the wild-type (WT) group, Mvd deficiency activated the expression of lipid metabolism-related proteins. CONCLUSION: We developed the first mouse model for PK research, enabling further studies on disease development and treatment approaches.

Decreased Imiquimod-Induced Psoriasis-Like Skin Inflammation in a Novel MvdF250S/+ Knock-In Mouse Model.

The mevalonate-diphosphate decarboxylase (MVD) gene, a member of the mevalonate pathway, plays a critical role in regulating the biosynthesis of cholesterol, steroid hormones, and non-steroid isoprenoids. Previous studies have suggested that the MVD c.746 T > C mutation is a major pathogenic gene of porokeratosis (PK), an autoinflammatory keratinization disease (AIKD) with unclear pathogenesis, few effective treatments, and no suitable animal model. To investigate the function of MvdF250S/+ mutation, we developed a novel MvdF250S/+ mouse model carrying an equivalent point mutation to the most common genetic variation among Chinese PK patients (MVDF249S/+) using CRISPR/Cas9 technology, which exhibited reduced cutaneous expression of Mvd protein. In the absence of external stimulation, MvdF250S/+ mice did not display specific phenotypes. However, upon induction with imiquimod (IMQ), MvdF250S/+ mice exhibited decreased susceptibility to skin acute inflammation compared to wild-type (WT) mice, as evidenced by reduced cutaneous proliferation and lower protein levels of IL-17a and IL-1ß. Additionally, after IMQ induction, the MvdF250S/+mice exhibited downregulated collagen generation and upregulated expression of Fabp3 compared to WT mice, whereas no significant changes in the key genes related to cholesterol regulation were found. Furthermore, the MvdF250S/+ mutation activated autophagy. Our findings provided insights into the biological function of MVD in the skin.

Elevated Expressions of BTN3A1 and RhoB in Psoriasis Vulgaris Lesions by an Immunohistochemical Study.

Psoriasis is a chronic, immune-mediated inflammatory disease which pathogenesis is closely linked to γδ T cells. Recently, a critical role for butyrophilin 3A1 (BTN3A1) in mediating the activation of Vγ9Vδ2 T cells, which are reported to redistribute from blood to the perturbed skin lesions in psoriasis, has been proposed. Additional molecular partners, including RhoB and periplakin, have also been speculated to interact with BTN3A1 in modulating Vγ9Vδ2 T-cell activation. Immunohistochemical staining was performed to examine the expressions of BTN3A1, RhoB, and the plakin family members, including periplakin, epiplakin, and envoplakin in the psoriasis vulgaris lesions as compared with the normal control. The expressions of BTN3A1 and RhoB were found significantly upregulated in the psoriatic lesions. Besides, a downregulation of periplakin and an upregulation of epiplakin were noticed in the psoriasis vulgaris lesions. Our data suggest that BTN3A1 and RhoB might participate in the pathogenesis of psoriasis through Vγ9Vδ2 T-cell responses. In addition, a potential involvement of the plakin protein family, especially periplakin and epiplakin, in psoriasis pathology was proposed.

Mvda is required for zebrafish early development.

BACKGROUND: The MVD gene mutations are identified in porokeratosis, which is considered a skin-specific autoinflammatory keratinization disease. However, the biological function of MVD gene remains largely unknown. Therefore, we analyzed the function of mvda gene, orthologous to the human MVD gene, in developing zebrafish. METHODS: Morpholino antisense oligonucleotide technique was used to generate mvda loss-of-function phenotypes. Knockdown of mvda was confirmed by RT-PCR and Sanger sequencing. Scanning and transmission electron microscopy were performed to analyze the morphology of the epidermis. Angiogenesis study was presented using the Tg(fli1a:EGFP)y1 transgenic strain. In addition, acridine orange staining was used to examine the apoptotic cells in vivo. RESULTS: As expected, the mvda morphants showed abnormal morphology of the epidermis. Moreover, we observed ectopic sprouts in trunk angiogenesis and impaired formation of the caudal vein plexus in the mvda-deficient zebrafish. Besides, increased apoptosis was found throughout the tail, heart, and eyes in mvda zebrafish morphants. CONCLUSIONS: These findings indicated the essential role of mvda in the early development of zebrafish. This was the first in vivo knockdown study of the zebrafish mvda gene, which might offer insight into the biological function of the human MVD gene.

Mvda is required for zebrafish early development

BACKGROUND: The MVD gene mutations are identified in porokeratosis, which is considered a skin-specific autoin- flammatory keratinization disease. However, the biological function of MVD gene remains largely unknown. Therefore, we analyzed the function of mvda gene, orthologous to the human MVD gene, in developing zebrafish. METHODS: Morpholino antisense oligonucleotide technique was used to generate mvda loss-of-function phenotypes. Knockdown of mvda was confirmed by RT-PCR and Sanger sequencing. Scanning and transmission electron microscopy were performed to analyze the morphology of the epidermis. Angiogenesis study was presented using the Tg(fli1a:EGFP)yl transgenic strain. In addition, acridine orange staining was used to examine the apoptotic cells in vivo. RESULTS: As expected, the mvda morphants showed abnormal morphology of the epidermis. Moreover, we observed ectopic sprouts in trunk angiogenesis and impaired formation of the caudal vein plexus in the mvda-deficient zebrafish. Besides, increased apoptosis was found throughout the tail, heart, and eyes in mvda zebrafish morphants. CONCLUSIONS: These findings indicated the essential role of mvda in the early development of zebrafish. This was the first in vivo knockdown study of the zebrafish mvda gene, which might offer insight into the biological function of the human MVD gene.