YTHDF2-Mediated m6A methylation inhibition by miR27a as a protective mechanism against hormonal osteonecrosis in BMSCs.

BACKGROUND: With the increasing incidence of steroid-induced necrosis of the femoral head (SNFH), numerous scholars have investigated its pathogenesis. Current evidence suggests that the imbalance between lipogenesis and osteoblast differentiation in bone marrow mesenchymal stem cells (BMSCs) is a key pathological feature of SNFH. MicroRNAs (miRNAs) have strong gene regulatory effects and can influence the direction of cell differentiation. N6-methyladenosine (m6A) is a prevalent epigenetic modification involved in diverse pathophysiological processes. However, knowledge of how miRNAs regulate m6A-related factors that affect BMSC differentiation is limited. OBJECTIVE: We aimed to investigate the role of miR27a in regulating the expression of YTHDF2 in BMSCs. METHODS: We compared miR27a, YTHDF2, and total m6A mRNA levels in SNFH-affected and control BMSCs. CCK-8 and TUNEL assays were used to assess BMSC proliferation and apoptosis. Western blotting and qRT‒PCR were used to measure the expression of osteogenic (ALP, RUNX2, and OCN) and lipogenic (PPARγ and C/EBPα) markers. Alizarin Red and Oil Red O staining were used to quantify osteogenic and lipogenic differentiation, respectively. miR27a was knocked down or overexpressed to evaluate its impact on BMSC differentiation and its relationship with YTHDF2. Bioinformatics analyses identified YTHDF2 as a differentially expressed gene in SNFH (ROC analysis) and revealed potential signaling pathways through GSEA. The effects of YTHDF2 silencing on the lipogenic and osteogenic functions of BMSCs were assessed. RESULTS: miR27a downregulation and YTHDF2 upregulation were observed in the SNFH BMSCs. miR27a knockdown/overexpression modulated YTHDF2 expression, impacting BMSC differentiation. miR27a silencing decreased m6A methylation and promoted osteogenic differentiation, while YTHDF2 silencing exerted similar effects. GSEA suggested potential signaling pathways associated with YTHDF2 in SNFH. CONCLUSION: miR27a regulates BMSC differentiation through YTHDF2, affecting m6A methylation and promoting osteogenesis. This finding suggests a potential therapeutic target for SNFH.

Serum metabolomics analysis of biomarkers and metabolic pathways in patients with colorectal cancer associated with spleen-deficiency and qi-stagnation syndrome or damp-heat syndrome: a prospective cohort study.

Objective: To profile the serum metabolites and metabolic pathways in colorectal cancer (CRC) patients associated with spleen-deficiency and qi-stagnation syndrome (SDQSS) or damp-heat syndrome (DHS). Methods: From May 2020 to January 2021, CRC patients diagnosed with traditional Chinese medicine (TCM) syndromes of SDQSS or DHS were enrolled. The clinicopathological data of the SDQSS and DHS groups were compared. The serum samples were analyzed by liquid chromatography-mass spectrometry (LC-MS). The variable importance in the projection >1, fold change ≥3 or ≤0.333, and P value ≤0.05 were used to identify differential metabolites between the two groups. Furthermore, areas under the receiver operating characteristic (ROC) curve > 0.9 were applied to select biomarkers with good predictive performance. The enrichment metabolic pathways were searched through the database of Kyoto Encyclopedia of Genes and Genomes. Results: 60 CRC patients were included (30 SDQSS and 30 DHS). The level of alanine aminotransferase was marginally significantly higher in the DHS group than the SDQSS group (P = 0.051). The other baseline clinicopathological characteristics were all comparable between the two groups. 23 differential serum metabolites were identified, among which 16 were significantly up-regulated and 7 were significantly down-regulated in the SDQSS group compared with the DHS group. ROC curve analysis showed that (S)-3-methyl-2-oxopentanoic acid, neocembrene, 1-aminocyclopropanecarboxylic acid, 3-methyl-3-hydroxypentanedioate, and nicotine were symbolic differential metabolites with higher predictive power. The top five enrichment signalling pathways were valine, leucine and isoleucine biosynthesis; lysosome; nicotine addiction; fructose and mannose metabolism; and pertussis. Conclusion: Our study identifies the differential metabolites and characteristic metabolic pathways among CRC patients with SDQSS or DHS, offering the possibility of accurate and objective syndrome differentiation and TCM treatment for CRC patients.

The potential effect of BMSCs with miR-27a in improving steroid-induced osteonecrosis of the femoral head.

Steroid induced osteonecrosis of the femoral head (ONFH) frequently leads to femoral head collapse and subsequent hip arthritis. This study aimed to investigate the potential therapeutic mechanism of miR-27a on steroid-induced ONFH. Levels of IL-6, TNF-α, miR-27a, Runx2, PPAR-γ and ApoA5 were first examined in bone marrow tissues from steroid-induced ONFH and controls. Subsequently, we overexpressed or knocked down miR-27a in bone marrow mesenchymal stem cells (BMSCs) and detected cell proliferation, osteogenic differentiation, adipogenic differentiation. In addition, miR-27a mimics and BMSCs were injected into the established steroid-induced ONFH rats, and the osteoprotective effects of both were evaluated. Dual luciferase reporter was used to test the targeting effect of miR-27a-3p and PPARG. miR-27a and Runx2 were lowly expressed in steroid-induced ONFH, PPAR-γ and ApoA5 were highly expressed. Overexpression of miR-27a in BMSCs promoted cell proliferation and osteogenic differentiation, inhibited adipogenic differentiation. Furthermore, increasing miR-27a and BMSCs obviously reduced bone loss in steroid induced ONFH rats. The expressions of Runx2 in BMSCs and steroid-induced ONFH rats was significantly up-regulated, while IL-6, TNF-α, PPAR-γ and ApoA5 were down-regulated with miR-27a overexpression. Additionally, PPARG was the target of miR-27a-3p. The results of the present study reveal a role for miR-27a in promoting osteogenesis and may have a synergistic effect with BMSCs.

Multivalley dark solitons in multicomponent Bose-Einstein condensates with repulsive interactions.

We obtain multivalley dark soliton solutions with asymmetric or symmetric profiles in multicomponent repulsive Bose-Einstein condensates by developing the Darboux transformation method. We demonstrate that the width-dependent parameters of solitons significantly affect the velocity ranges and phase jump regions of multivalley dark solitons, in sharp contrast to scalar dark solitons. For double-valley dark solitons, we find that the phase jump is in the range [0,2π], which is quite different from that of the usual single-valley dark soliton. Based on our results, we argue that the phase jump of an n-valley dark soliton could be in the range [0,nπ], supported by our analysis extending up to five-component condensates. The interaction between a double-valley dark soliton and a single-valley dark soliton is further investigated, and we reveal a striking collision process in which the double-valley dark soliton is transformed into a breather after colliding with the single-valley dark soliton. Our analyses suggest that this breather transition exists widely in the collision processes involving multivalley dark solitons. The possibilities for observing these multivalley dark solitons in related Bose-Einstein condensates experiments are discussed.

Diagnosis of a case of homozygous constitutional MMR-deficiency by the use of a gene-panel in a non-consanguineous family: A case report.

Constitutional MMR-deficiency syndrome (CMMRD) is a rare but severe hereditary syndrome of pediatric cancer caused by bi-allelic pathogenic variants in one of the mismatch DNA repair genes (MMR): MLH1, MSH2, MSH6, and PMS2. This syndrome occurs when patients inherit altered alleles from both of their heterozygote parents affected by Lynch syndrome. In total, ~150 patients have been identified at present, the majority of which were Caucasian. The present case report described the diagnosis of CMMRD in a Chinese boy with atypical clinical features caused by a homozygous pathogenic variant in MSH6 gene, identified by the use of a gene-panel. This is the first case diagnosed in a Chinese (Asian) population. These data indicated that CMMRD affects patients of any ethnic origin, implying a potentially high prevalence. Notably, the homozygous bi-allelic inactivation was caused by a random event in an apparently closed population, as opposed to a consanguineous marriage, additionally suggesting a high risk of CMMRD for individuals living in relatively closed populations.

Physical simulation and theoretical evolution for ground fissures triggered by underground coal mining.

Underground coal mining activities are prone to cause movement and breakage in geological strata and also lead to mining subsidence and even ground fissures. Along the direction working panel advancing, ground fissures may occur in roof in front and/or behind working panel. However, the investigations of previous similarity tests in lab only emphasize on the region behind working panel. By improving strata material property in construction and mounting artificial pressure devices, two physical simulation tests were conducted and successfully investigated the simulated results. Then, the mechanical model of "cantilever beam and elastic foundation beam" was proposed to calculate the stress distribution and the crack initiation angle in overlying strata and it well explains the mechanisms of ground fissures generation and propagation. Results show that, the maximum internal force in roof always occurred in front of working panel. However, because the void space in gob due to excavation is large enough to cause the bend and rotation of roof strata, compare to the triaxially compressed region in front of working panel, the roof always broke off at some positions above gob since the stress concentration resulting from such bend and rotation of strata could easily reach the limit strength of strata rocks. Also, the length of cantilever beam changed dynamically as respect to the panel advancing and the breakage intervals. Thus, the breakage position where the internal force first reached the limit tensile strength is not fixed and there will be two different kinds of relative positions between the crack initiation point and the working panel. The crack initiation direction is always perpendicular to the internal force, and the crack propagation direction is affected by the initiation angle, overburden-separation degree and the position of the hydraulic shields. If there is no overburden-separation or less, the roofs will break off as a composite beam and the propagation direction will be roughly along the central line between the initial broken point and the support position. Otherwise, the roof strata will bend with the support shields moving forward, then the fracture angle will be close to the initiation angle and the fault surface will be stepped.

[Subtotal colectomy with cecorectal end-side anastomosis in the treatment of slow transit constipation].

OBJECTIVE: To study the feasibility of subtotal colectomy with cecorectal end-side anastomosis for slow transit constipation. METHODS: Retrospective analysis was performed on 23 patients with colon slow transit constipation treated by subtotal colectomy with cecorectal end-side anastomosis in our department from March 2006 to April 2013. The main measure outcome was the curative effect on constipation by this type of surgery. RESULTS: Twenty-three patients were successfully treated. Anastomotic leakage occurred in one case, and urinary retention in 1 case, while no anastomotic stricture, abdominal bleeding, abdominal hernia, incontinence and other complications occurred. During follow-up of 2 months to 7 years, defecation frequency was 1-4 times a day with no need of antidiarrheal agents. Each time of defecation was less than 5 min. All the patients had no recurrence of constipation. CONCLUSION: Subtotal colectomy with cecorectal end-side anastomosis can be used to treat colon slow transit constipation, while accurate preoperative evaluation and strict indications for the surgery is the key to success.