Accurate timing of myelination is crucial for the proper functioning of the central nervous system. Here, we identified a de novo heterozygous mutation in TMEM63A (c.1894G>A; p. Ala632Thr) in a 7-year-old boy exhibiting hypomyelination. A Ca²⁺ influx assay suggested that this is a loss-of-function mutation. To explore how TMEM63A deficiency causes hypomyelination, we generated Tmem63a knockout mice. Genetic deletion of TMEM63A resulted in hypomyelination at postnatal day 14 (P14) arising from impaired differentiation of oligodendrocyte precursor cells (OPCs). Notably, the myelin dysplasia was transient, returning to normal levels by P28. Primary cultures of Tmem63a^-/- OPCs presented delayed differentiation. Lentivirus-based expression of TMEM63A but not TMEM63A_A632T rescued the differentiation of Tmem63a^-/- OPCs in vitro and myelination in Tmem63a^-/- mice. These data thus support the conclusion that the mutation in TMEM63A is the pathogenesis of the hypomyelination in the patient. Our study further demonstrated that TMEM63A-mediated Ca²⁺ influx plays critical roles in the early development of myelin and oligodendrocyte differentiation.
Animals ; Cell Differentiation/physiology* ; Oligodendroglia/metabolism* ; Mice, Knockout ; Mice ; Male ; Myelin Sheath/metabolism* ; Humans ; Child ; Cells, Cultured ; Oligodendrocyte Precursor Cells/metabolism*

Humans ; Consensus ; Hypersensitivity ; Desensitization, Immunologic/adverse effects* ; Immunotherapy/adverse effects* ; Injections, Subcutaneous ; Allergens

BACKGROUNDEstrogen is involved in suppression of colon cancer development and exerts its function via estrogen receptors alpha and beta (ERalpha, ERbeta). The recently identified ERalpha46 resulted from exon 1-deletion from the 66-kDa full length form of ERalpha66 is devoid of the transactivation domain AF-1, whose function remains largely unknown.

METHODSIn this study, we compared the expression of ERalpha46 mRNA in 32 normal colorectal tissues and their matched colorectal cancer tissues by real-time quantitative polymerase chain reaction (PCR). Human colon adenocarcinoma cell HT-29, that has low endogenous expression of ERalpha46, was transfected with ERalpha46-expression vector; methyl thiazolyl tetrazolium (MTT) assay, flow cytometry, DNA fragmentation and TUNEL staining were used to evaluate the proliferation and apoptosis status of the cells in the presence of 17beta-oestradiol.

RESULTSHigher ERalpha46 mRNA levels were observed in normal colorectal tissues than in the corresponding cancer tissues. ERalpha46-transfected cells showed a significantly decreased growth rate than control cells and an accumulation of cells in the G(0/1) phase and a reduced proportion of cells in G(2)/M phase after exposed to 10(-8) mol/L 17beta-oestradiol. There were also more positive TUNEL stained cells in ERalpha46-transfected cells than the control cells in the presence of 17beta-oestradiol (P < 0.05).

CONCLUSIONSThese data suggest that ERalpha46 may be involved in the development and/or progression of colorectal cancer via mediating growth inhibition and apoptosis of cancer cells in the presence of 17beta-oestradiol.

Adult ; Aged ; Apoptosis ; Colorectal Neoplasms ; genetics ; pathology ; Estradiol ; pharmacology ; Estrogen Receptor alpha ; genetics ; Female ; G1 Phase ; HT29 Cells ; Humans ; Male ; Middle Aged ; Mutation