Astroglial Activation Is Exacerbated in a Down Syndrome Mouse Model.

Down syndrome (DS), also known as trisomy 21, is one of the most common chromosomal disorders associated with intellectual disability. Mouse models are valuable for mechanistic and therapeutic intervention studies. The purpose of this study was to investigate astroglial anomalies in Dp16, a widely used DS mouse model. Brain sections were prepared from one-month-old Dp16 mice and their littermates, immunostained with an anti-GFAP or anti-S100B antibody, and imaged to reconstruct astroglial morphology in three dimensions. No significant difference in the number of astrocytes was found in either the hippocampal CA1 region or cortex between Dp16 and WT mice. However, the average astroglial volume in Dp16 was significantly (P < 0.05) greater than that in WT, suggesting the astroglial activation. Reanalysis of the single-nucleus RNA sequencing data indicated that the genes differentially expressed between WT and Dp16 astrocytes were associated with synapse organization and neuronal projection. In contrast, in vitro cultured neonatal astrocytes did not exhibit significant morphological changes. The expression of Gfap in in vitro cultured Dp16 astrocytes was not increased as it was in in vivo hippocampal tissue. However, after treatment with lipopolysaccharides, the inflammatory response gene IFNß increased significantly more in Dp16 astrocytes than in WT astrocytes. Overall, our results showed that the increase in astrogliogenesis in DS was not apparent in the early life of Dp16 mice, while astrocyte activation, which may be partly caused by increased responses to inflammatory stimulation, was significant. The inflammatory response of astrocytes might be a potential therapeutic target for DS intellectual disability.

Establishment and characterization of ZJUCHi003: an induced pluripotent stem cell line from a patient with Temple-Baraitser/Zimmermann-Laband syndrome carrying KCNH1 c.1070G > A (p.R357Q) variant.

Pathogenic variants of the KCNH1 gene can cause dominant-inherited Temple-Baraitser/Zimmermann-Laband syndrome with severe mental retardation, seizure, gingival hyperplasia and nail hypoplasia. This study established an induced pluripotent stem cell (iPSC) line using urinary cells from a girl with KCNH1 recurrent/hotspot pathogenic variant c.1070G > A (p.R357Q). The cell identity, pluripotency, karyotypic integrity, absence of reprogramming virus and mycoplasma contamination, and differential potential to three germ layers of the iPSC line, named as ZJUCHi003, were characterized and confirmed. Furthermore, ZJUCHi003-derived neurons manifested slower action potential repolarization process and wider action potential half-width than the normal neurons. This cell line will be useful for investigating the pathogenic mechanisms of KCNH1 variants-associated symptoms, as well as for evaluating novel therapeutic approaches.

Single-nucleus RNA sequencing reveals cell type-specific transcriptome alterations of Down syndrome hippocampus using the Dp16 mouse model.

BACKGROUND: Down syndrome (DS), the most frequently occurring human chromosomal disorder, is caused by trisomy 21. The exact molecular effects of trisomy on certain cell populations in the brain remain poorly understood. OBJECTIVE: The purpose of this study was to investigate the effects of trisomy on the transcriptomes of various types of neurons and nonneuronal cells in the hippocampus. METHODS: A total of 8993 nuclei from the WT and 6445 nuclei from the Dp16 hippocampus were analyzed by single-nucleus RNA sequencing (snRNA-seq). Cell clustering was achieved by the Seurat program. RESULTS: Hippocampal cells were grouped into multiple neuronal and nonneuronal populations. Only a limited number of trisomic genes were upregulated (q < 0.001) over 1.25-fold in a specific type of hippocampal cell. Specifically, deregulation of genes associated with synaptic signaling and organization was observed in multiple cell populations, including excitatory neurons, oligodendrocytes, and microglia. This observation suggests the potential importance of synapse deficits in DS. Interestingly, GO annotation of the upregulated genes suggested potential activation of the immune system by hippocampal excitatory neurons. Fewer trisomic genes were altered in nonneuronal cells than in neurons. Notably, microglial transcriptome analysis revealed significantly (q < 0.001) increased expression of C1qb and C1qc, which suggested potential involvement of complement-mediated synapse loss mediated by microglia in DS. CONCLUSION: The trisomy-related hippocampal deficits should be driven by a small amount, not all, of the trisomic genes in a specific type of cell. Our work may help to narrow down both the molecular and cellular targets for future gene therapies in DS.

Laparoscopic Proximally Extended Colorectal Resection With Two-Stage Turnbull-Cutait Pull-Through Coloanal Anastomosis for Late Complications of Chronic Radiation Proctopathy.

Background: Chronic radiation proctopathy (CRP) is a common complication after radiation therapy for pelvic malignancies. Compared with diversion surgery, resection surgery removes the damaged tissue completely to avoid the risks of recurrence and improve patients' outcome. Hence, resection surgery could be an optimal surgical approach when CRP is complicated by late complications. This study aimed to describe a modified surgical procedure of resection surgery and report its preliminary efficacy and safety in treating patients with CRP with late complications. Methods: We retrospectively reviewed the patients who were diagnosed with CRP with late complications and underwent the modified surgical procedure of laparoscopic proximally extended colorectal resection with two-Stage Turnbull-Cutait pull-through coloanal anastomosis (PE-Bacon) between November 2019 and October 2020 in the Sixth Affiliated Hospital of Sun Yat-sen University. Results: A total of 15 patients were performed the modified laparoscopic procedure of PE-Bacon, of which 1 patient underwent conversion from laparoscopic to open operation for intraoperative massive hemorrhage. Overall, the major (Clavien-Dindo III-V) postoperative complications occurred in 1 patient, anastomotic leakage was observed in 2 (13.3%) patients, and anastomotic stricture was observed in 4 (26.7%) patients. No patient had to be reoperated and died. Up to now, at the average follow-up of (524.40 ± 108.39) days, the preoperative symptoms of 93.3% (14/15) patients were relieved, with nine patients achieved complete remission, five patients only suffered minor symptoms. Because of the progression of radiation uropathy, one patient still had a vesicovaginal fistula as pre-operative complication. Colostomy reversal has been performed on 8 (53.3%) patients at an average postoperative duration of 299.5 ± 92.68 days, among whom only 2 patients suffered from major Low Anterior Resection Syndrome (LARS) until now. Conclusions: Laparoscopic PE-Bacon surgery is a safe and feasible surgical procedure for late complications of CRP with low morbidity and high symptom remission rate.

Lin28b is involved in curcumin-reversed paclitaxel chemoresistance and associated with poor prognosis in hepatocellular carcinoma.

Chemoresistance remains a big challenge in hepatocellular carcinoma (HCC) treatment. Several studies indicated that RNA-binding protein Lin28B serves an oncogenic role in HCC, but its activity in HCC chemotherapy has never been assessed. In this study, we found that overexpression of Lin28B significantly increased the paclitaxel chemoresistance in two different HCC cells lines while silencing Lin28B reduced the chemoresistance in paclitaxel-resistance HCC cells. Curcumin, a natural anti-cancer agent, increased the sensitivity of HCC cells to paclitaxel through inhibiting NF-κB stimulated Lin28B expression both in vitro and in vivo. Furthermore, by analyzing TCGA (The Cancer Genome Atlas) LIHC (liver hepatocellular carcinoma) and GSE14520 databases, we found that Lin28B was highly upregulated in HCC tissue compared with that in normal tissue and associated with α­fetoprotein levels, and that patients with Lin28B higher expression had a significant shorter overall survival time than those with Lin28B lower expression. Our data reveal that Lin28B may serve as a predictive biomarker and a treatment target to reverse HCC chemotherapy resistance in future clinical practice.