Objective:To investigate the effect of the transcriptional coactivator Mediator 1 (Med1) on mouse hair regeneration, and to explore potential mechanisms.Methods:Med1 flox/flox C57BL/6J mice were mated with K14-Cre mice, and the mice with epidermis-specific knockout of Med1 gene, namely K14-Cre-expressing Med1 flox/flox mice (knockout group) , were obtained by using the Cre-Loxp system, while Med1 flox/flox mice without K14-Cre expression served as control group. Mice in the two groups (3 mice in each group) were raised together for 8 weeks followed by dorsal hair removal. Hair regeneration was observed for 12 consecutive days after hair removal. After 12 days, all mice in the two groups were sacrificed, their depilated and non-depilated dorsal skin tissues were resected, and total RNA was extracted from the tissues. Real-time quantitative PCR was performed to determine the mRNA expression of hair keratin genes, vitamin D receptor/β-catenin pathway-related genes, and genes associated with maintenance of hair follicle stem cell proliferation and quiescence. Paraffin-embedded sections of depilated and non-depilated mouse skin tissues were prepared, and immunofluorescence staining was conducted to determine the number of stem cells in the hair follicle bulge. Two-independent-sample t test was used for comparisons between two groups. Results:From days 0 to 12 after depilation, hair regeneration was delayed in the depilated skin area in the knockout group compared with the control group. Real-time quantitative PCR showed significantly decreased mRNA relative expression levels of hair keratin genes Ha1 and Krt2-16, vitamin D receptor/β-catenin pathway-related genes S100a3, Dlx3 and Tubb3, and genes associated with maintenance of hair follicle stem cell proliferation and quiescence including Lhx2, Sox9 and Nfatc1 in the depilated skin tissues in the knockout group (22.09 ± 12.32, 2.07 ± 0.20, 0.02 ± 0.01, 12.36 ± 2.12, 1.75 ± 0.46, 0.39 ± 0.02, 4.42 ± 0.76, 0.44 ± 0.07, respectively) compared with the control group (70.53 ± 9.46, 7.76 ± 0.49, 0.05 ± 0.01, 26.16 ± 2.96, 2.60 ± 0.14, 0.71 ± 0.09, 11.93 ± 0.42, 0.75 ± 0.04, respectively; t = 5.40, 18.64, 3.89, 6.57, 3.04, 6.10, 15.03, 6.18, respectively, all P < 0.05) . Immunofluorescence staining showed that the number of CD34 +K15 + hair follicle stem cells in the hair follicle bulge in both depilated and non-depilated skin tissues was significantly lower in the knockout group than in the control group. Conclusion:Med1 gene knockout may down-regulate the expression of downstream genes of the vitamin D receptor/β-catenin pathway and genes associated with maintenance of hair follicle stem cell proliferation and quiescence (Sox9, Nfatc1 and Lhx2) , and reduce the number of hair follicle stem cells, leading to hair follicle differentiation disorder and hair regeneration delay.

Objective:To explore the risk factors and outcomes of central nervous system(CNS)complications associated with hematopoietic stem cell transplantation(HSCT).Methods:A total of 550 recipient after HSCT in the department of hematology of Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology from January 1 2019 to August 31 2021were enrolled.According to the occurrence of CNS complications, they were divided into the CNS group(24 cases)and the non CNS group(526 cases). The clinical information and prognosis were compared.We further analyzed the risk factors associated with CNS complications, and conducted multivariate logistic regression on statistically significant indicators.Cox regression analysis is conducted on prognostic factors such as age, gender and risk degree.Results:A total of 550 recipients were enrolled, of which 330 underwent allo-HSCT, and others received auto-HSCT.A total of 24 cases (4.36%)had CNS complications, of which 4 cases had 2 types of CNS complications.The type of CNS complications included intracranial infection(8 cases, 28.57%), transplantation-associated thrombotic microangiopathy(TA-TMA)(6 cases, 21.43%), central tumor invasion(4 cases, 14.29%), intracranial hemorrhage(4 cases, 14.29%), leucodystrophy(2 cases, 7.14%)and unexplained encephalopathy(4 cases, 14.29%). Logistic regression analysis of risk factors related to CNS complications showed that, Platelet implantation time( β=0.084, OR=1.088, P=0.048), CMV infection( β=1.295, OR=3.65, P=0.008)is positively correlated with the occurrence of CNS complications in HSCT recipients but age( β=-0.052, OR=0.949, P=0.004)is negatively correlated with it.Nine of the 24 cases(37.50%)who experienced CNS complications died, including 3 cases of intracranial infection, 3 cases of cerebral hemorrhage, 2 cases of TMA, and 1 case of unexplained encephalopathy.Platelet implantation time is an independent risk factor for poor prognosis of CNS complications in HSCT recipients. Conclusions:Our results indicated that, age, CMV infection and platelet implantation time were associated with the occurrence of CNS complications after HSCT.Platelet implantation time is an independent risk factor for poor prognosis of CNS complications in HSCT recipients.