MYCT1 inhibits hematopoiesis in diffuse large B-cell lymphoma by suppressing RUNX1 transcription.

BACKGROUND: The abnormality of chromosomal karyotype is one factor causing poor prognosis of lymphoma. In the analysis of abnormal karyotype of lymphoma patients, three smallest overlap regions were found, in which MYCT1 was located. MYCT1 is the first tumor suppressor gene cloned by our research team, but its studies relating to the occurrence and development of lymphoma have not been reported. METHODS: R banding analyses were employed to screen the abnormality of chromosomal karyotype in clinical specimen and MYCT1 over-expression cell lines. FISH was to monitor MYCT1 copy number aberration. RT-PCR and Western blot were to detect the mRNA and protein levels of the MYCT1 and RUNX1 genes, respectively. The MYCT1 and RUNX1 protein levels in clinical specimen were evaluated by immunohistochemical DAB staining. The interaction between MYCT1 and MAX proteins was identified via Co-IP and IF. The binding of MAX on the promoter of the RUNX1 gene was detected by ChIP and Dual-luciferase reporter assay, respectively. Flow cytometry and CCK-8 assay were to explore the effects of MYCT1 and RUNX1 on the cell cycle and proliferation, respectively. RESULTS: MYCT1 was located in one of three smallest overlap regions of diffuse large B-cell lymphoma, it altered chromosomal instability of diffuse large B-cell lymphoma cells. MYCT1 negatively correlated with RUNX1 in lymphoma tissues of the patients. MAX directly promoted the RUNX1 gene transcription by binding to its promoter region. MYCT1 may represses RUNX1 transcription by binding MAX in diffuse large B-cell lymphoma cells. MYCT1 binding to MAX probably suppressed RUNX1 transcription, leading to the inhibition of proliferation and cell cycle of the diffuse large B-cell lymphoma cells. CONCLUSION: This study finds that there is a MYCT1-MAX-RUNX1 signaling pathway in diffuse large B-cell lymphoma. And the study provides clues and basis for the in-depth studies of MYCT1 in the diagnosis, treatment and prognosis of lymphoma.

Endothelial Cell-Derived Let-7c-Induced TLR7 Activation on Smooth Muscle Cell Mediate Vascular Wall Remodeling in Moyamoya Disease.

Moyamoya disease (MMD) is characterized by frequent migration and phenotypic transformation of vascular smooth muscle cells (VSMCs) in the intima layer of blood vessels. However, the underlying mechanism is unclear. Toll-like receptor (TLR) 7 is abundantly expressed in smooth muscle cells (SMCs) in multiple vascular diseases, which might be linked to the disease-associated vascular remodeling. In the present study, the expression of TLR7 in MMD vessels was examined using the superficial temporal artery (STA) and middle cerebral artery (MCA) from MMD patients. Furthermore, the effect of TLR7 activation on the VSMC phenotype switch in vitro and vascular remodeling in vivo was assessed using a 9.4Tesla MRI. Our results demonstrated that the TLR7 and microRNA Let-7c expression are upregulated in VSMCs and the plasma of MMD patients, respectively. Additionally, TLR7 stimulation by Let-7c or Imiquimod induces a synthetic phenotype switch in VSMCs. Mechanistic studies revealed that Akt/mTOR signaling is responsible for this TLR-induced VSMC phenotypic switch. The Let-7c or Imiquimod treatment also resulted in reduced blood flow of internal carotid arteries (ICAs) in an in vivo model, while TLR7 inhibition attenuated the ICA stenosis. Besides, Let-7c was also found to be elevated in the hypoxic endothelial cells. Taken together, our study demonstrates that Let-7c released by endothelial cells under hypoxic conditions may activate TLR7 on VSMCs, ultimately leading to the phenotype switch and vascular wall remodeling. These findings thus elucidate the putative mechanisms underlying progressive stenosis of blood vessels in MMD and provide prospective therapeutic targets for further exploration.

Construction and validation of a fatty acid metabolism risk signature for predicting prognosis in acute myeloid leukemia.

BACKGROUND: Fatty acid metabolism has been reported to play important roles in the development of acute myeloid leukemia (AML), but there are no prognostic signatures composed of fatty acid metabolism-related genes. As the current prognostic evaluation system has limitations due to the heterogeneity of AML patients, it is necessary to develop a new signature based on fatty acid metabolism to better guide prognosis prediction and treatment selection. METHODS: We analyzed the RNA sequencing and clinical data of The Cancer Genome Atlas (TCGA) and Vizome cohorts. The analyses were performed with GraphPad 7, the R language and SPSS. RESULTS: We selected nine significant genes in the fatty acid metabolism gene set through univariate Cox analysis and the log-rank test. Then, a fatty acid metabolism signature was established based on these genes. We found that the signature was as an independent unfavourable prognostic factor and increased the precision of prediction when combined with classic factors in a nomogram. Gene Ontology (GO) and gene set enrichment analysis (GSEA) showed that the risk signature was closely associated with mitochondrial metabolism and that the high-risk group had an enhanced immune response. CONCLUSION: The fatty acid metabolism signature is a new independent factor for predicting the clinical outcomes of AML patients.

BAY61­3606 attenuates neuroinflammation and neurofunctional damage by inhibiting microglial Mincle/Syk signaling response after traumatic brain injury.

Neuroinflammatory processes mediated by microglial activation and subsequent neuronal damage are the hallmarks of traumatic brain injury (TBI). As an inhibitor of the macrophage­inducible C­type lectin (Mincle)/spleen tyrosine kinase (Syk) signaling pathway, BAY61­3606 (BAY) has previously demonstrated anti­inflammatory effects on some pathological processes, such as acute kidney injury, by suppressing the inflammatory macrophage response. In the present study, the potential effects of BAY on microglial phenotype and neuroinflammation after TBI were investigated. BAY (3 mg/kg) was first administered into mice by intraperitoneal injection after TBI induction in vivo and microglia were also treated with BAY (2 µM) in vitro. The levels of inflammatory factors in microglia were assessed using reverse transcription­quantitative PCR and ELISA. Cortical neuron, myelin sheath, astrocyte and cerebrovascular endothelial cell markers were detected using immunofluorescence. The levels of components of the Mincle/Syk/NF­κB signaling pathway [Mincle, phosphorylated (p)­Syk and NF­κB], in addition to proteins associated with inflammation (ASC, caspase­1, TNF­α, IL­1ß and IL­6), apoptosis (Bax and Bim) and tight junctions (Claudin­5), were measured via western blotting and ELISA. Migration and chemotaxis of microglial cells were evaluated using Transwell and agarose spot assays. Neurological functions of the mice were determined in vivo using the modified neurological severity scoring system and a Morris water maze. The results of the present study revealed that the expression levels of proteins in the Mincle/Syk/NF­κB signaling pathway (including Mincle, p­Syk and p­NF­κB), inflammatory cytokines (TNF­α, IL­1ß and IL­6), proteins involved in inflammation (ASC and caspase­1), apoptotic markers (Bax and Bim) and the tight junction protein Claudin­5 were significantly altered post­TBI. BAY treatment reversed these effects in both the cerebral cortex extract­induced cell model and the controlled cortical impact mouse model. BAY was also revealed to suppress activation of the microglial proinflammatory phenotype and microglial migration. In addition, BAY effectively attenuated TBI­induced neurovascular unit damage and neurological function deficits. Taken together, these findings provided evidence that BAY may inhibit the Mincle/Syk/NF­κB signaling pathway in microglia; this in turn could attenuate microglia­mediated neuroinflammation and improve neurological deficits following TBI.

The Prognostic Value and Function of HOXB5 in Acute Myeloid Leukemia.

BACKGROUND: Currently, cytogenetic and genetic markers are the most important for risk stratification and treatment of patients with acute myeloid leukemia (AML). Despite the identification of many prognostic factors, relatively few have made their way into clinical practice. Therefore, the identification of new AML biomarkers is useful in the prognosis and monitoring of AML and contributes to a better understanding of the molecular basis of the disease. Homeobox (HOX) genes are transcription factors that lead to cell differentiation blockade and malignant self-renewal. However, the roles of HOX genes in AML are still not fully understood and need further exploration, which may provide new strategies for the prognosis and monitoring of AML. METHODS: We analyzed the RNA sequencing and clinical data from The Cancer Genome Atlas (TCGA), VIZOME, GSE13159, and GSE9476 cohorts. Analyses were performed with GraphPad 7, the R language, and several online databases. We applied quantitative polymerase chain reaction, Western Blotting, CCK8 cell proliferation assays, and flow cytometry to verify the conclusions of the bioinformatics analysis. RESULTS: We identified HOXB5 as the only gene among the HOX family that was not only elevated in AML but also a significant prognostic marker in AML patients. HOXB5 was highly expressed in AML patients with NPM1, FLT3, or DNMT3A mutations and was expressed at the highest level in patients with NPM1-FLT3-DNMT3A triple-mutant AML. Gene Ontology analysis and gene set enrichment analysis revealed that HOXB5 showed a negative correlation with the myeloid cell differentiation signature and that the tumor necrosis factor/nuclear factor κB signaling pathway was involved in the molecular mechanism. Moreover, we performed in silico protein-protein interaction analysis and 450K TCGA DNA methylation data analysis and found that HOXB5 interacted with two HOX genes (HOXA7 and HOXB4) that were commonly regulated by DNA methylation levels. CONCLUSION: HOXB5 is associated with the malignant development of AML and may be a treatment target and biomarker for AML prognosis prediction.

The clinical characteristics and prognosis of COVID-19 patients with cerebral stroke: A retrospective study of 113 cases from one single-centre.

To explore the clinical characteristics and prognosis of COVID-19 patients with cerebral stroke. A total of 2,474 COVID-19 patients from February 10th to March 24th, 2020 were admitted and treated in two branches (Optic Valley and Sino-French New City branch) of the Tongji Hospital. Data on the clinical characteristics, laboratory parameters and prognosis of COVID-19 patients with or without cerebral stroke were collected and comparatively analysed. Of the 2,474 COVID-19 patients, 113 (4.7%) patients had cerebral stroke and 25 (1.0%) patients had new-onset stroke. Eighty-eight (77.9%) patients in the previous-stroke group had cerebral ischaemia, while 25 (22.1%) patients in the new-onset stroke group had cerebral ischaemia. Most COVID-19 patients with stroke were elderly with more comorbidities such as hypertension, diabetes and heart diseases than patients without stroke. Laboratory examinations showed hypercoagulation and elevated serum parameters such as IL-6, cTnI, NT pro-BNP and BUN. Consciousness disorders, a long disease course and poor prognosis were also more commonly observed in stroke patients. The mortality rate of stroke patients was almost double (12.4% vs. 6.9%) that of patients without stroke. In addition, age, male sex and hypertension were independent predictors for new cerebral stroke in COVID-19 patients. In conclusion, the high risk of new-onset stroke must be taken into consideration when treating COVID-19 patients with an elderly age combined with a history of hypertension. These patients are more vulnerable to multiorgan dysfunction and an overactivated inflammatory response, in turn leading to an unfavourable outcome and higher mortality rate.

MYCT1 inhibits the EMT and migration of laryngeal cancer cells via the SP1/miR-629-3p/ESRP2 pathway.

MYCT1 has an inhibitory effect on the migration of laryngeal cancer cells, although the underlying molecular mechanism remains unknown. In this study, we aimed to explore the mechanism of MYCT1 in the epithelial-mesenchymal transition (EMT) and migration of laryngeal cancer cells. We found that MYCT1 significantly decreased the expression of miR-629-3p but increased the expression of ESRP2 in laryngeal cancer cells. The expression of miR-629-3p and ESRP2 in laryngeal cancer tissues showed significantly positive and negative correlations with patient metastasis, respectively. miR-629-3p was confirmed to repress the expression of ESRP2 by targeting its 3'UTR. SP1 was verified to be a direct transcription factor for miR-629-3p and a downstream target of MYCT1. Moreover, MYCT1 inhibited the EMT and migration of laryngeal cancer cells through the SP1/miR-629-3p/ESRP2 pathway. Taken together, our results establish a novel MYCT1 signaling pathway in the EMT and migration of laryngeal cancer cells, thus providing important insights for further studying the pathway in the diagnosis and treatment of laryngeal cancer.

Interleukin 4 inhibits high mobility group box-1 protein-mediated NLRP3 inflammasome formation by activating peroxisome proliferator-activated receptor-γ in astrocytes.

High mobility group box-1 protein (HMGB-1) is one of the most important DAMPs and has been previously shown to promote the formation of the NOD-like receptor with pyrin domain containing-3 (NLRP3) inflammasome in microglia. Interleukin 4 (IL4) is a Th2-derived cytokine that plays a significant role in the function of various immune cells. However, the underlying molecular mechanism by which IL4 signaling antagonizes NLRP3 inflammasome is poorly characterized. In particular, whether IL4 could modulate NLRP3 inflammasome in astrocytes remains unknown. In the present study, we elucidated this phenomenon and the mechanism by which IL4 inhibits HMGB1-mediated NLRP3 inflammasome formation in astrocytes. For this purpose, we cultured and extracted primary astrocytes, setup different concentrations of HMGB1, and used immunofluorescence and western blotting to detect NLRP3 inflammasome formation, including NLRP3, ASC and caspase-1, and signaling changes in the nuclear factor κB (NF-κB). Meanwhile, BAY 11-7082 and IL4 were added with HMGB1 to observe the NLRP3 inflammasome and changes in NF-κB expression. Our data showed that HMGB1 could effectively promote NLRP3 inflammasome formation by activating NF-κB in astrocytes. This effect can be inhibited by BAY 11-7082, a NF-κB inhibitor. Meanwhile, IL4 could activate PPARγ via the STAT6 singling pathway and inhibit NF-κB activation, significantly decreasing formation of the NLRP3 inflammasome complex. Our study demonstrated that the NLRP3 inflammasome complex is also expressed in astrocytes, and IL4 could inhibit HMGB1-mediated NLRP3 inflammasome formation, through negative regulation of NF-κB activity and promotion of PPARγ activation.

TLR4 signal ablation attenuated neurological deficits by regulating microglial M1/M2 phenotype after traumatic brain injury in mice.

Traumatic brain injury (TBI) initiates inflammatory responses that result in an enduring cascade of secondary neuronal loss and behavioural impairment. Toll-like receptor 4 (TLR4), predominantly expressed by microglia, recognizes damage-associated molecular patterns (DAMPs) and regulates inflammatory processes. Interestingly, the switch of microglial M1/M2 phenotypes after TBI is highly important regarding damage and restoration of neurological function. Therefore, we investigated the role and mechanisms of the TLR4 signalling pathway in regulating microglial M1/M2 phenotypes. Using a controlled cortical impact (CCI) model, we found that TLR4 knockout (KO) mice exhibited decreased infarct volumes and improved outcomes in behavioural tests. In addition, mice lacking TLR4 had higher expression of M2 phenotype biomarkers but lower expression of M1 phenotype biomarkers. Compared with microglia derived from wild-type (WT) mice, increased expression of M2 phenotype biomarkers and decreased expression of M1 phenotype biomarkers were also noted in primary cultures of microglia from TLR4 KO mice. In TLR4 KO mice, the expression levels of downstream signalling molecules of TLR4, such as active Rac-1 and phospho-AKT, were higher, while MyD88 and phospho-NF-κB p65 expression levels were lower than in WT mice. Our results demonstrate that the absence of TLR4 induces microglial polarization toward the M2 phenotype and promotes microglial migration and, in turn, alleviates the development of neuroinflammation, which indicates potential neuroprotective effects in the TBI mouse model. Furthermore, up-regulation of IL-4 expression in TLR4 KO mice could contribute to anti-inflammatory functions and promote microglial polarization toward the M2 phenotype, which might be mediated by active Rac-1 expression. Taken together, TLR4 deficiency contributes to regulating microglia to switch to the M2 phenotype, which ameliorates neurological impairment after TBI.