Super-enhancer-driven Sorting Nexin 5 expression promotes dopaminergic neuronal ferroptosis in Parkinson's disease models.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease worldwide. Recent studies revealed that the ferroptosis pathway is involved in the death process of dopaminergic neurons in PD. The aberrant endosomal sorting pathway, which results in aberrant iron level in eukaryotic cells, may serve a role in the ferroptosis pathway in PD condition. However, its specific molecular mechanisms remained unclear. In the present study, we performed chromatin immunoprecipitation (ChIP) assay, the rank ordering of super-enhancers (ROSE) algorithm, and RNA interference (RNAi) to explore the regulatory mechanism of PD-specific super-enhancer (SE) in the endosomal sorting pathway and ferroptosis pathway of 6-OHDA-lesioned rats and cells. The ChIP assay and ROSE algorithm results showed that there are specific SEs expression in 6-OHDA-lesioned SNc of PD rats, and the most significant expression gene is Sorting Nexin 5 (SNX5). SNX5 silencing by RNAi experiments significantly decreased the level of ferroptosis in 6-OHDA-lesioned PC12 cells, suggesting the correlation between the SNX5, ferroptosis, and PD. In conclusion, this study investigated the mechanism by which PD-specific SE driven SNX5 promoted the ferroptosis level in PD models. This study further improved the understanding of the mechanism of ferroptosis during PD injury and provided potential therapeutic targets and clinical diagnostic markers in PD condition.

Wedelolactone Promotes the Chondrogenic Differentiation of Mesenchymal Stem Cells by Suppressing EZH2.

Background and Objectives: Osteoarthritis (OA) is a degenerative disease that leads to the progressive destruction of articular cartilage. Current clinical therapeutic strategies are moderately effective at relieving OA-associated pain but cannot induce chondrocyte differentiation or achieve cartilage regeneration. We investigated the ability of wedelolactone, a biologically active natural product that occurs in Eclipta alba (false daisy), to promote chondrogenic differentiation. Methods and Results: Real-time reverse transcription-polymerase chain reaction, immunohistochemical staining, and immunofluorescence staining assays were used to evaluate the effects of wedelolactone on the chondrogenic differentiation of mesenchymal stem cells (MSCs). RNA sequencing, microRNA (miRNA) sequencing, and isobaric tags for relative and absolute quantitation analyses were performed to explore the mechanism by which wedelolactone promotes the chondrogenic differentiation of MSCs. We found that wedelolactone facilitates the chondrogenic differentiation of human induced pluripotent stem cell-derived MSCs and rat bone-marrow MSCs. Moreover, the forkhead box O (FOXO) signaling pathway was upregulated by wedelolactone during chondrogenic differentiation, and a FOXO1 inhibitor attenuated the effect of wedelolactone on chondrocyte differentiation. We determined that wedelolactone reduces enhancer of zeste homolog 2 (EZH2)-mediated histone H3 lysine 27 trimethylation of the promoter region of FOXO1 to upregulate its transcription. Additionally, we found that wedelolactone represses miR-1271-5p expression, and that miR-1271-5p post-transcriptionally suppresses the expression of FOXO1 that is dependent on the binding of miR-1271-5p to the FOXO1 3'-untranscribed region. Conclusions: These results indicate that wedelolactone suppresses the activity of EZH2 to facilitate the chondrogenic differentiation of MSCs by activating the FOXO1 signaling pathway. Wedelolactone may therefore improve cartilage regeneration in diseases characterized by inflammatory tissue destruction, such as OA.

Atractylodes lancea volatile oils target ADAR2-miR-181a-5p signaling to mesenchymal stem cell chondrogenic differentiation.

Atractylodeslancea Rhizoma (Rhizoma atractylodis [RA]) has long been recommended for the treatment of arthritis in traditional Chinese medicine, but its mechanism of action is still unclear. RA contains a large amount of Atractylodes lancea volatile oils (Atr). In this study, we investigated whether Atr can promote mesenchymal stem cells (MSCs) chondrogenic differentiation. The Atr were extracted from RA by steam distillation method, and the effect of Atr on MSCs was detected by the CCK8 assay. The optimal concentration of Atr for MSCs cultivation was 3 µg/ml. The differentially expressed miR-181a-5p was screened by miRNA microarray assay, and its mimics and inhibitors were transfected into MSCs. It was found that the inhibitor of miR-181a-5p could upregulate cartilage-specific genes such as SOX9, COL2A1, and ACAN. Meanwhile, we also found that the expression of gene editing enzyme ADAR2 was significantly increased in the chondrogenic differentiation of MSCs induced by Atr, and the bases of precursor sequence of miR-181a-5p were changed from A to G. After ADAR2 deletion, the expression of cartilage-specific genes was significantly down-regulated and the precursor sequence bases of miR-181a-5p were not changed. Bioinformatics analysis revealed that the predicted target gene of miR-181a-5p was yingyang1 (YY1), and the targeting relationship was verified by dual-luciferase reporter assay. After deleting YY1, the expression of cartilage-specific genes was significantly down-regulated. In conclusion, our study demonstrated that Atr can promote chondrogenic differentiation of MSC through regulation of the ADAR2-miR-181a-5p signaling pathway. This may provide a new insight into the possible mechanism of traditional Chinese medicine (Atr) in treating inflammatory joint diseases.

Berberine blocks inflammasome activation and alleviates diabetic cardiomyopathy via the miR­18a­3p/Gsdmd pathway.

Diabetic cardiomyopathy (DCM) is a cardiovascular disease which has been reported as a major cause of mortality worldwide for several years. Berberine (BBR) is a natural compound extracted from a Chinese herb, with a clinically reported anti­DCM effect; however, its molecular mechanisms have not yet been fully elucidated. The present study indicated that BBR markedly alleviated DCM by inhibiting IL­1ß secretion and the expression of gasdermin D (Gsdmd) at the post­transcriptional level. Considering the importance of microRNAs (miRNAs/miRs) in the regulation of the post­transcriptional process of specific genes, the ability of BBR to upregulate the expression levels of miR­18a­3p by activating its promoter (­1,000/­500) was examined. Notably, miR­18a­3p targeted Gsdmd and abated pyroptosis in high glucose­treated H9C2 cells. Moreover, miR­18a­3p overexpression inhibited Gsdmd expression and improved biomarkers of cardiac function in a rat model of DCM. On the whole, the findings of the present study indicate that BBR alleviates DCM by inhibiting miR­18a­3p­mediated Gsdmd activation; thus, BBR may be considered a potential therapeutic agent for the treatment of DCM.

Nsun4 and Mettl3 mediated translational reprogramming of Sox9 promotes BMSC chondrogenic differentiation.

The chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) has been used in the treatment and repair of cartilage defects; however, the in-depth regulatory mechanisms by which RNA modifications are involved in this process are still poorly understood. Here, we found that Sox9, a critical transcription factor that mediates chondrogenic differentiation, exhibited enhanced translation by ribosome sequencing in chondrogenic pellets, which was accompanied by increased 5-methylcytosine (m5C) and N6-methyladenosine (m6A) levels. Nsun4-mediated m5C and Mettl3-mediated m6A modifications were required for Sox9-regulated chondrogenic differentiation. Interestingly, we showed that in the 3'UTR of Sox9 mRNA, Nsun4 catalyzed the m5C modification and Mettl3 catalyzed the m6A modification. Furthermore, we found that Nsun4 and Mettl3 co-regulated the translational reprogramming of Sox9 via the formation of a complex. Surface plasmon resonance (SPR) assays showed that this complex was assembled along with the recruitment of Ythdf2 and eEF1α-1. Moreover, BMSCs overexpressing Mettl3 and Nsun4 can promote the repair of cartilage defects in vivo. Taken together, our study demonstrates that m5C and m6A co-regulate the translation of Sox9 during the chondrogenic differentiation of BMSCs, which provides a therapeutic target for clinical implications.

Moxibustion Protects Dopaminergic Neurons in Parkinson's Disease through Antiferroptosis.

Ferroptosis is associated with neural degeneration of dopaminergic neurons in Parkinson's disease (PD). However, how to control the level of ferroptosis in PD remains unclear. Clinically, moxibustion has been used to treat PD and has an apparent therapeutic effect on improving the motor symptoms of PD. In the present study, the PD rat model was constructed by two-point stereotactic 6-hydroxydopamine injection. Then, moxibustion was used to treat the PD rats. The expression of glutathione peroxidase 4 (GPX4) and Ferritin Heavy Chain 1 (FTH1), the level of reactive oxygen species (ROS), and the morphology of mitochondrial were detected to evaluate the level of ferroptosis. The results showed that moxibustion treatment of Shi's moxa sticks could reduce the behavioral score, alleviate the level of ferroptosis, decrease mitochondrial damage, and improve dopaminergic neuron survival. In conclusion, the present study results indicated that Shi's moxa sticks could effectively suppress the level of ferroptosis, thereby improving the survival of dopaminergic neurons in the SNpc of PD rats, which may provide a promising complementary and alternative therapy for PD patients.

miR­335 promotes ferroptosis by targeting ferritin heavy chain 1 in in vivo and in vitro models of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease characterized by the selective loss of dopaminergic neurons in the substantia nigra (SN). In a previous study, the authors demonstrated that ferritin heavy chain 1 (FTH1) inhibited ferroptosis in a model of 6­hydroxydopamine (6­OHDA)­induced PD. However, whether and how microRNAs (miRNAs/miRs) modulate FTH1 in PD ferroptosis is not yet well understood. In the present study, in vivo and in vitro models of PD induced by 6­OHDA were established. The results in vivo and in vitro revealed that the levels of the ferroptosis marker protein, glutathione peroxidase 4 (GPX4), and the PD marker protein, tyrosine hydroxylase (TH), were decreased in the model group, associated with a decreased FTH1 expression and the upregulation of miR­335. In both the in vivo and in vitro models, miR­335 mimic led to a lower FTH1 expression, exacerbated ferroptosis and an enhanced PD pathology. The luciferase 3'­untranslated region reporter results identified FTH1 as the direct target of miR­335. The silencing of FTH1 in 6­OHDA­stimulated cells enhanced the effects of miR­335 on ferroptosis and promoted PD pathology. Mechanistically, miR­335 enhanced ferroptosis through the degradation of FTH1 to increase iron release, lipid peroxidation and reactive oxygen species (ROS) accumulation, and to decrease mitochondrial membrane potential (MMP). On the whole, the findings of the present study reveal that miR­335 promotes ferroptosis by targeting FTH1 in in vitro and in vivo models of PD, providing a potential therapeutic target for the treatment of PD.

RNA Binding Protein Motif 3 Inhibits Oxygen-Glucose Deprivation/Reoxygenation-Induced Apoptosis Through Promoting Stress Granules Formation in PC12 Cells and Rat Primary Cortical Neurons.

As a sensitive cold-shock protein, RNA binding protein motif 3 (RBM3) exhibits a neuroprotective function in the condition of brain injury. However, how RBM3 is involved in acute ischemic stroke by affecting stress granules (SGs) remains unclear. Here, we established an oxygen-glucose deprivation/reperfusion (OGD/R) model in rat primary cortical neurons and PC12 cells to explore the potential mechanism between RBM3 and SG formation in acute ischemic/reperfusion (I/R) condition. The immunofluorescence results showed that the SG formation significantly decreased in rat primary cortical neurons and PC12 cells during the reperfusion period after 6 h of OGD stimulation. The western blot results, flow cytometry analysis, and cell viability assessment showed that the RBM3 expression and ratio of cell viability significantly decreased, while the rate of apoptosis increased in PC12 cells during the reperfusion period after 6 h of OGD stimulation. Co-immunoprecipitation (Co-IP) and immunofluorescence indicated that RBM3 and GTPase-activating protein-binding protein 1 (G3BP1) colocalized cytoplasm of PC12 cells after 6 h of OGD stimulation when the SGs formation reached the highest level. Besides, overexpression and knockdown of the RBM3 were achieved via plasmid transfection and CRISPR-Cas9 technology, respectively. The results of overexpression and knockdown of RBM3 gene illustrated the pivotal role of RBM3 in affecting SG formation and apoptosis level in OGD-treated PC12 cells. In conclusion, RBM3 could combine with G3BP1 resulted in increasing stress granules generation in rat primary cortical neurons and PC12 cells after 6 h of oxygen-glucose deprivation (OGD) injury, which ultimately reduced the apoptosis in OGD-induced cells. Our study may enable a new promising target for alleviating ischemia-reperfusion injury in cells.

Methyltransferase 3 Mediated miRNA m6A Methylation Promotes Stress Granule Formation in the Early Stage of Acute Ischemic Stroke.

The modification of methyltransferase-like (METTL) enzymes plays important roles in various cellular responses by regulating microRNA expression. However, how m6A modification is involved in stress granule (SG) formation in the early stage of acute ischemic stroke by affecting the biogenesis processing of microRNAs remains unclear. Here, we established a middle cerebral artery occlusion (MCAO) model in rats and an oxygen-glucose deprivation/reperfusion (OGD/R) model in primary cortical neurons and PC12 cells to explore the potential mechanism between m6A modification and SG formation. The in vivo results showed that the level of infarction and apoptosis increased while SG formation decreased significantly within the ischemic cortex with improved reperfusion time after 2 h of ischemia. Consistent with the in vivo data, an inverse association between the apoptosis level and SG formation was observed in PC12 cells during the reperfusion period after 6 h of OGD stimulation. Both in vivo and in vitro results showed that the expression of METTL3 protein, m6A and miR-335 was significantly decreased with the reperfusion period. Overexpression of the METTL3 and METTL3 gene-knockdown in PC12 cells were achieved via plasmid transfection and CRISPR-Cas9 technology, respectively. Overexpression or knockdown of METTL3 in oxygen-glucose deprivation of PC12 cells resulted in functional maturation of miR-335, SG formation and apoptosis levels. In addition, we found that miR-335 enhanced SG formation through degradation of the mRNA of the eukaryotic translation termination factor (Erf1). In conclusion, we found that METTL3-mediated m6A methylation increases the maturation of miR-335, which promotes SG formation and reduces the apoptosis level of injury neurons and cells, and provides a potential therapeutic strategy for AIS.

Wedelolactone facilitates Ser/Thr phosphorylation of NLRP3 dependent on PKA signalling to block inflammasome activation and pyroptosis.

OBJECTIVES: Wedelolactone exhibits regulatory effects on some inflammatory diseases. However, the anti-inflammatory mechanism of wedelolactone has not been entirely unravelled. Therefore, the present study focuses on investigating the mechanism of wedelolactone on NLRP3 inflammasome in macrophages and its influence on MSU-induced inflammation. MATERIALS AND METHODS: BMDM, J774A.1 and PMA-differentiated THP-1 macrophages were primed with LPS and then stimulated with ATP or nigericin or MSU crystal in the presence or absence of wedelolactone. The cell lysates and supernatants were collected to detect NLRP3 inflammasome components such as NLRP3, ASC and caspase 1, as well as pyroptosis and IL-1ß production. In addition, the anti-inflammatory effects of wedelolactone on MSU-induced peritonitis and arthritis mice were also evaluated. RESULTS: We found that wedelolactone broadly inhibited NLRP3 inflammasome activation and pyroptosis and IL-1ß secretion. Wedelolactone also block ASC oligomerization and speck formation. The inhibitory effects of wedelolactone were abrogated by PKA inhibitor H89, which also attenuated wedelolactone-enhanced Ser/Thr phosphorylation of NLRP3 at PKA-specific sites. Importantly, wedelolactone could abate MSU-induced IL-1ß production and neutrophils migration into peritoneal cavity, and reduced caspase 1 (p20) and IL-1ß expression in the joint tissue of MSU-induced arthritis. CONCLUSION: Our results indicate that wedelolactone promotes the Ser/Thr phosphorylation of NLRP3 to inhibit inflammasome activation and pyroptosis partly through potentiating PKA signalling, thus identifying its potential use for treating MSU-induced peritonitis and gouty arthritis.

miR­335 promotes stress granule formation to inhibit apoptosis by targeting ROCK2 in acute ischemic stroke.

Under harmful environmental conditions, stress granules (SGs), macromolecular aggregates that are associated with cell survival and death, are produced in the eukaryotic cytoplasm. However, whether and how microRNAs (miRNAs/miRs) modulate SG formation induced by acute ischemic stroke has not been investigated. In the present study, a rat model of middle cerebral artery occlusion (MCAO) was utilized and miRNA array profiling and reverse transcription­quantitative polymerase chain reaction were performed. The results revealed that miR­335 was downregulated during acute ischemic stroke, which was concomitant with reduced SG formation, enhanced apoptosis levels and increased Rho associated protein kinase 2 (ROCK2) expression. In the MCAO rat and serum­free cell models, miR­335 treatment upregulated SG formation, alleviated the ischemia­induced infarction, and decreased ROCK2 protein expression and apoptosis levels. By contrast, when compared with miR­335 treatment, the inhibition of miR­335 resulted in reduced SG formation and higher ROCK2 expression and apoptosis levels. Target prediction analysis and luciferase 3'­untranslated region reporter assay identified ROCK2 as the direct target of miR­335. Furthermore, ROCK2 silencing enhanced SG formation and attenuated the level of apoptosis in the serum­free cell model. In addition, ROCK2 silencing markedly inhibited the effect of miR­335 on SG formation and apoptosis levels. Unexpectedly, the phosphorylation of T­cell intracellular antigen­1 was significantly inhibited by miR­335 in the MCAO rat model, which provides a reasonable explanation for the promotional effect of miR­335 on SG formation by specifically targeting ROCK2. In conclusion, these results demonstrate that miR­335 promotes SG formation and inhibits apoptosis by reducing ROCK2 expression in acute ischemic stroke, which provides a possible therapeutic target for brain injury.