Intervertebral disc (IVD) degeneration contributes largely to pathoanatomical and degenerative changes of spinal structure that increase the risk of low back pain. Apoptosis in nucleus pulposus (NP) can aggravate IVD degeneration, and increasing studies have shown that interventions targeting NP cell apoptosis can ameliorate IVD degeneration, exhibiting their potential for use as therapeutic strategies. Recent data have shown that advanced glycation end products (AGEs) accumulate in NP tissues in parallel with the progression of IVD degeneration and form a microenvironment of oxidative stress. This study examined whether AGEs accumulation aggravates NP cell apoptosis and IVD degeneration, and explored the mechanisms underlying these effects. We observed that the viability and proliferation of human NP cells were significantly suppressed by AGEs treatment, mainly due to apoptosis. Furthermore, activation of the mitochondrial apoptosis pathway was detected after AGEs treatment. In addition, the molecular data showed that AGEs could significantly aggravate the generation of mitochondrial reactive oxygen species and prolonged activation of the mitochondrial permeability transition pore, as well as the increased level of Bax protein and decreased level of Bcl-2 protein in mitochondria. These effects could be reduced by antioxidant (2-(2,2,6,6-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride (MitoTEMPO) and Visomitin (SKQ1). Importantly, we identified that impairment of Sirtuin3 (SIRT3) function and the mitochondrial antioxidant network were vital mechanisms in AGEs-induced oxidative stress and secondary human NP cell apoptosis. Finally, based on findings that nicotinamide mononucleotide (NMN) could restore SIRT3 function and rescue human NP cell apoptosis through adenosine monophosphate-activated protein kinase and peroxisome proliferator-activated receptor-γ coactivator 1α (AMPK-PGC-1α) pathway in vitro, we confirmed its protective effect on AGEs-induced IVD degeneration in vivo. In conclusion, our data demonstrate that SIRT3 protects against AGEs-induced human NP cell apoptosis and IVD degeneration. Targeting SIRT3 to improve mitochondrial redox homeostasis may represent a potential therapeutic strategy for attenuating AGEs-associated IVD degeneration.
Abstract N6 methyladenosine (m 6 A) is one of the most prevalent epitranscriptomic modifications of mRNAs, and plays a critical role in various bioprocesses. Bone-derived mesenchymal stem cells (BMSCs) can attenuate apoptosis of nucleus pulposus cells (NPCs) under compression; however, the underlying mechanisms are poorly understood. This study showed that the level of m 6 A mRNA modifications was decreased, and the autophagic flux was increased in NPCs under compression when they were cocultured with BMSCs. We report that under coculture conditions, RNA demethylase ALKBH5-mediated FIP200 mRNA demethylation enhanced autophagic flux and attenuated the apoptosis of NPCs under compression. Specific silencing of ALKBH5 results in impaired autophagic flux and a higher proportion of apoptotic NPCs under compression, even when cocultured with BMSCs. Mechanistically, we further identify that the m 6 A “reader” YTHDF2 is likely to be involved in the regulation of autophagy, and lower m 6 A levels in the coding region of FIP200 lead to a reduction in YTHDF2-mediated mRNA degradation of FIP200, a core molecular component of the ULK1 complex that participates in the initiating process of autophagy. Taken together, our study reveals the roles of ALKBH5-mediated FIP200 mRNA demethylation in enhancing autophagy and reducing apoptosis in NPCs when cocultured with BMSCs.
Chronic low back pain (LBP) is a significant global health concern, often linked to vertebral bone marrow lesions (BML), particularly fatty replacement (FR). This study aims to explore the relationship between the gut microbiome, serum metabolome, and FR in chronic LBP patients. Serum metabolomic profiling and gut microbiome analysis were conducted in chronic LBP patients with and without FR (LBP + FR, n = 40; LBP, n = 40) and Healthy Controls (HC, n = 31). The study investigates alterations in branched-chain amino acids (BCAAs) levels and identifies key microbial species associated with BCAA metabolism. In vitro experiments elucidate the role of BCAAs in adipogenesis of bone marrow mesenchymal stem cells (BM-MSCs) via the SIRT4 pathway. Chronic LBP patients with FR exhibit depleted BCAA levels in their serum metabolome, along with alterations in the gut microbiome. Specific microbial species, including Ruminococcus gnavus, Roseburia hominis, and Lachnospiraceae bacterium 8 1 57FAA, are identified as influential in BCAA metabolism and BM-MSCs metabolism. In vitro experiments demonstrate the ability of BCAAs to induce BM-MSCs adipogenesis through SIRT4 pathway activation. This study sheds light on the intricate relationship between the disturbed gut ecosystem, serum metabolites, and FR in chronic LBP. Dysbiosis in the gut microbiome may contribute to altered BCAA degradation, subsequently promoting BM-MSCs adipogenesis and FR. Understanding these interactions provides insights for targeted therapeutic strategies to mitigate chronic LBP associated with FR by restoring gut microbial balance and modulating serum metabolite profiles.
Intervertebral disc degeneration (IVDD) has been reported to be the most prevalent contributor to low back pain, posing a significant strain on the healthcare systems on a global scale. Currently, there are no approved therapies available for the prevention of the progressive degeneration of intervertebral disc (IVD); however, emerging regenerative strategies that aim to restore the normal structure of the disc have been fundamentally promising. In the last decade, mesenchymal stem cells (MSCs) have received a significant deal of interest for the treatment of IVDD due to their differentiation potential, immunoregulatory capabilities, and capability to be cultured and regulated in a favorable environment. Recent investigations show that the pleiotropic impacts of MSCs are regulated by the production of soluble paracrine factors. Exosomes play an important role in regulating such effects. In this review, we have summarized the current treatments for disc degenerative diseases and their limitations and highlighted the therapeutic role and its underlying mechanism of MSC-derived exosomes in IVDD, as well as the possible future developments for exosomes.
A sensitive, specific method has been developed for simultaneous determination of neoeriocitrin and naringin in rat plasma using liquid chromatography-tandem mass spectrometry. With hesperidin as the internal standard, plasma samples were prepared by protein precipitation with methanol. Analysis was carried out on an ACQUITY UPLC BEH C18 column using acetonitrile-water (20:80, v/v) as the mobile phase. Detection was performed by means of electrospray ionization mass spectrometry in negative ion mode with multiple reaction monitoring. Linear calibration curves of neoeriocitrin and naringin were obtained over the concentration ranges of 15.0-960 ng/mL and 12.0-1200 ng/mL, respectively. The intra- and inter-day precisions were within 9.7% and 7.6% for neoeriocitrin and 7.8% and 12.9% for naringin. The accuracy was from -4.3% to 0.43% for neoeriocitrin and from -3.8% to 3.0% for naringin. The validated method was successfully applied to the pharmacokinetic study of neoeriocitrin and naringin in rats after oral administration of a Chinese compound formulation, gushudan.
This study aims to explore the high-risk factors of carbapenem-resistant Enterobacteriaceae (CRE) infection of hospitalised patients in high-risk departments. This study is a multicentre, retrospective study. CRE screening positive patients from 1 January 2016 to 31 December 2018 of high-risk departments in five tertiary first-class teaching hospitals in Beijing collect the patients' CRE test specimen information, CRE infection information and outcomes. The patients were divided into a colonisation group and an infection group for comparative analysis. A logistic regression model was established to explore the risk factors of CRE infection. Subgroup analysis was conducted according to invasive procedures and the type of the infection. In total, 344 patients were included in this study, including 85 (24.71%) colonisation and 259 (75.29%) infection; 36.09% CRE colonisation converted to infection, and the mean conversion time from colonisation to infection was 6.5 (4.0, 18.8) days. Renal disease, granulocytosis, invasive procedures and the time from hospital stay to positive CRE were the risk factors for CRE infection. The subgroup analysis showed that the rate of CRE infection in the invasive group was higher than in the non-invasive group (P < 0.001), and the rate of exacerbation or death in the invasive group was also higher than in the non-invasive group (P = 0.019). The average length of ICU and hospitalisation in the healthcare-associated infection group were significantly higher than those in the community infection group, but there was no difference in the proportion of final exacerbation or death between them (P = 0.727). Kidney disease, granulocytosis, invasive procedures and CRE detection time are the risk factors for CRE infection. Carrying out CRE screening in patients as early as possible and taking effective intervention measures in time to avoid adverse consequences is all important.
Mitochondrial biogenesis and function are controlled by anterograde regulatory pathways involving more than 1000 nuclear-encoded proteins. Transcriptional networks controlling the nuclear-encoded mitochondrial genes remain to be fully elucidated. Here, we show that histone demethylase LSD1 KO from adult mouse liver (LSD1-LKO) reduces the expression of one-third of all nuclear-encoded mitochondrial genes and decreases mitochondrial biogenesis and function. LSD1-modulated histone methylation epigenetically regulates nuclear-encoded mitochondrial genes. Furthermore, LSD1 regulates gene expression and protein methylation of nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1), which controls the final step of NAD+ synthesis and limits NAD+ availability in the nucleus. Lsd1 KO reduces NAD+-dependent SIRT1 and SIRT7 deacetylase activity, leading to hyperacetylation and hypofunctioning of GABPβ and PGC-1α, the major transcriptional factor/cofactor for nuclear-encoded mitochondrial genes. Despite the reduced mitochondrial function in the liver, LSD1-LKO mice are protected from diet-induced hepatic steatosis and glucose intolerance, partially due to induction of hepatokine FGF21. Thus, LSD1 orchestrates a core regulatory network involving epigenetic modifications and NAD+ synthesis to control mitochondrial function and hepatokine production.
Additional file 1. Correlation analysis of the six deacetylation genes, CHD3, HDAC9, LYPLA1, HDAC3, LYPLAL1 and SIRT5 with the DEGs from the GSE56081 dataset.
The present study is to evaluate the clinical outcomes of the sequential correction of severe and rigid kyphoscoliosis.Between January 2014 and December 2020, 27 adults with severe and rigid kyphoscoliosis underwent sequential correction combined with posterior grade 4 or grade 5 spinal osteotomy. Radiological parameters, including the major curve Cobb angle, kyphotic angle, coronal imbalance, and sagittal vertical axis (SVA), were compared. Patient self-reported health-related quality of life (HRQOL) scores were used to evaluate clinical outcomes.The mean major curve Cobb angle improved from 134.30 ± 13.24° to 44.48 ± 9.34° immediately after surgery and to 46.11 ± 8.94° at the final follow-up. The mean kyphotic angle improved from 112.15 ± 20.28° to 38.63 ± 15.00° immediately after surgery and to 39.85 ± 14.92° at the final follow-up. The mean preoperative major curve Cobb angle of grade 5 spinal osteotomy group was higher than that of grade 4 spinal osteotomy group. Coronal imbalance and SVA slightly improved. The patient self-reported HRQOL scores improved postoperatively and at the final follow-up. Activity, appearance and total scores of the SRS-22 of the grade 5 spinal osteotomy group at the final follow-up were significantly better than those of the grade 4 spinal osteotomy group.Sequential correction combined with posterior grade 4 or grade 5 spinal osteotomies is an excellent and safe treatment for severe and rigid kyphoscoliosis in adults. Sequential correction combined with posterior grade 5 spinal osteotomies can be used to correct severe and rigid kyphoscoliosis with higher major curve Cobb angle.
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