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*

Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.

Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.

Objective To identify the clinical characteristics and prognostic factors of young patients with sporadic rectal cancer liver metastasis(RCLM).Methods The clinical data of young RCLM patients at 45 years or under(n=40,as younger patient group)in Peking University First Hospital from January 2016 to January 2021 were reviewed,meanwhile,elder RCLM patient group were comprised of 82 patients older than 45-year-old in a 1:2 ratio.Proportions of categorical variables were compared between young patients and old patients.The clinicopathologic parameters were analyzed with univariate and multivariate Cox regression models and Kaplan-Meier method for demonstrating survival differences between the maximum diameter of liver metastasis and local therapy.Results One hundred and twenty-two RCLM patients were identified,the 1-,3-and 5-year survival rates of young patient group were 97.5%,47.5%,15.0%,those of elder patient group were 84.1%,26.8%,9.8%,respectively.The differences in BMI(P=0.008),primary tumor with obstruction and bleeding(P=0.006),synchronous rectal cancer liver metastases(P=0.005),the maximum diameter of liver metastasis>3 cm(P=0.019)were statistically significant between the two groups.And univariate and multivariate analyses showed that age(P=0.003),N stage(P=0.007),local therapy for liver metastases(P=0.047)and the maximum diameter of liver metastasis(P=0.030)were independent risk factors for influencing the prognosis of RCLM patients;curative resection or not of primary tumor(P=0.035)and the maximum diameter of liver metastasis(P=0.041)were independent risk factors for influencing the prognosis of young RCLM patients.Kaplan-Maier curve demonstrated survival differences between the maximum diameter of liver metastasis and local therapy for liver metastasis in RCLM patients(log-rank P=0.000).Conclusions Although with later staging of initial tumor station,young RCLM patients may obtain better survival benefit compared with old patients.Higher degree of lymph node metastasis,local therapy for liver metastases and the maximum diameter of liver metastasis>3 cm indicates poor prognosis in RCLM patients,and without curative resection of primary tumor and maximum diameter of liver metastasis are also considered as the independent poor prognostic factors of young RCLM patients.Local therapy for liver metastases appears to play an important role in the treatment strategy of RCLM patients.

Objective To investigate the incidence rate,clinical characteristics,and prognosis of neonatal stroke in Shenzhen,China.Methods Led by Shenzhen Children's Hospital,the Shenzhen Neonatal Data Collaboration Network organized 21 institutions to collect 36 cases of neonatal stroke from January 2020 to December 2022.The incidence,clinical characteristics,treatment,and prognosis of neonatal stroke in Shenzhen were analyzed.Results The incidence rate of neonatal stroke in 21 hospitals from 2020 to 2022 was 1/15 137,1/6 060,and 1/7 704,respectively.Ischemic stroke accounted for 75％(27/36);boys accounted for 64％(23/36).Among the 36 neonates,31(86％)had disease onset within 3 days after birth,and 19(53％)had convulsion as the initial presentation.Cerebral MRI showed that 22 neonates(61％)had left cerebral infarction and 13(36％)had basal ganglia infarction.Magnetic resonance angiography was performed for 12 neonates,among whom 9(75％)had involvement of the middle cerebral artery.Electroencephalography was performed for 29 neonates,with sharp waves in 21 neonates(72％)and seizures in 10 neonates(34％).Symptomatic/supportive treatment varied across different hospitals.Neonatal Behavioral Neurological Assessment was performed for 12 neonates(33％,12/36),with a mean score of(32±4)points.The prognosis of 27 neonates was followed up to around 12 months of age,with 44％(12/27)of the neonates having a good prognosis.Conclusions Ischemic stroke is the main type of neonatal stroke,often with convulsions as the initial presentation,involvement of the middle cerebral artery,sharp waves on electroencephalography,and a relatively low neurodevelopment score.Symptomatic/supportive treatment is the main treatment method,and some neonates tend to have a poor prognosis.

Objective This study aimed to understand the infection rates of Leishmania parasites in sandflies,dogs,and humans in Wangping Street,Mentougou District,Beijing,to provide decision-making recommendations for the prevention and control of the Leishmania infection(Kala-Azar).Methods From early April to late November 2021,sandflies were trapped to screen for Leishmania parasites using Leishmania-specific PCR in Mentougou District,Beijing.Simultaneously,residents and suspected dogs were tested to detect possible Leishmania infections using the rk39 immunochromatographic test strip and Leishmania-specific PCR tests.Results A total of 4 280 Phlebotomus chinensis were captured from Mentougou District and no Leishmania parasites were detected.Nine of 36 suspected sick dogs tested positive for Leishmania parasites.No positive human blood samples were obtained from the 73 residents around the index patient's activity area.Conclusions A canine Kala-Azar outbreak occurred in Wangping town.Timely surveillance and control measures are urgently needed in the Mentougou District.

Humans ; Mpox (monkeypox) ; China

In this study, the mechanism of Xiaoyan Lidan formula (XYLDF) against 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-collidine (DDC)-induced chronic intrahepatic cholestasis (CIHC) in mice was investigated based on metabolomics, molecular docking and pharmacological methods. In the pharmacodynamics study, a dosage of 5 g·kg^-1 (clinical equivalent) XYLDF was administered in DDC-induced mice, then the effect of XYLDF against CIHC was evaluated by measuring the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP) as well as total bilirubin (TBIL) in serum and observing liver histopathological changes. All experiments were approved by the Ethical Committee Experimental Animal Center of Guangzhou University of Chinese Medicine (ZYD-2021-001). The serum metabolites of mice in each group were detected and identified based on ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry, and the relevant biological pathways and molecular key targets were further enriched. Molecular docking technology was used to further evaluate the binding activity of the main active ingredients of XYLDF with potential targets. Subsequently, the in vitro experiment was conducted for the validation of the vital target. The results showed that compared with the model group, XYLDF significantly decreased the levels of ALT, AST, AKP and TBIL in the serum of CIHC mice, as well as alleviated inflammatory infiltration and hepatocyte necrosis in liver tissue. According to the metabonomic study, a total of 35 differential metabolites was identified as biomarkers associated with cholestasis, 12 of which were significantly recovered by XYLDF treatment. These biomarkers were involved in the pathways of primary bile acid biosynthesis and linoleic metabolism, which are closely related to the mechanism of XYLDF against CIHC. Protein-protein interaction network indicated that cytochrome P450 3A4 (CYP3A4) and cytochrome P450 1A1 (CYP1A1) are significant potential targets with good binding properties with six major active ingredients of XYLDF. Furthermore, it was found that 4-methoxy-5-hydroxycanthin-6-one, dehydroandrographolide and isodocarpin, three of the main active components in XYLDF, markedly induced the expression of CYP3A4 mRNA in vitro. This study revealed that XYLDF mainly mediates the biosynthesis of bile acids in CIHC mice to improve liver tissue lesions and bile efflux disorders, among which, CYP3A4 is the key target in the protection of XYLDF against CIHC. This research provides a reference for further elucidation of the pharmacological mechanism of XYLDF.

A blood-brain barrier microfluidic chip platform for studying the permeability of active components in traditional Chinese medicine was developed. This model used primary human brain microvascular endothelial cells on a microfluidic chip consisting of two perpendicularly-crossing channels and a single layer porous polycarbonate membrane. The physiological shear stress in the human vasculature was also modeled in this device. Cell viability on the chip was monitored by cell staining and immunofluorescence staining. The cells spread well and the structure of an intercellular adhesion protein was satisfactory. The permeability of fluorescent tracers and three model drugs and the functional expression of P-glycoprotein (P-gp)on the blood-brain barrier were investigated. The results show that the apparent permeability coefficients (P_app) of the fluorescent tracers and three model drugs were consistent with those reported in the literature, and P-gp on the chip showed normal function, indicating that there was a complete structure and a functional BBB. The permeability of six active components of traditional Chinese medicine was investigated through this microfluidic chip and the drug concentration was determined by HPLC-MS/MS to obtain the P_app of each component. The P_app of corydaline was (4.51 ± 1.90)×10^-7 cm·s^-1, the P_app of tetrahydropalmatine was (9.10 ± 6.59)×10^-7 cm·s^-1, and the P_app of imperatorin was (9.38 ± 2.53)×10^-7 cm·s^-1; the concentration of isoimperatorin, baicalin and chlorogenic acid was below the limit of quantification, which suggested that isoimperatorin, baicalin and chlorogenic acid have poor permeability in this BBB chip. This blood-brain barrier microfluidic platform possesses a complete barrier function and near-physiological conditions and could be a valuable in vitro tool for drug permeability evaluation.