Heme oxygenase-1 protects spinal cord neurons from hydrogen peroxide-induced apoptosis via suppression of Cdc42/MLK3/MKK7/JNK3 signaling

Metformin alleviates spinal cord injury by inhibiting nerve cell ferroptosis through upregulation of heme oxygenase-1 expression

JOURNAL/nrgr/04.03/01300535-202409000-00037/figure1/v/2024-01-16T170235Z/r/image-tiff Previous studies have reported upregulation of heme oxygenase-1 in different central nervous system injury models. Heme oxygenase-1 plays a critical anti-inflammatory role and is essential for regulating cellular redox homeostasis. Metformin is a classic drug used to treat type 2 diabetes that can inhibit ferroptosis. Previous studies have shown that, when used to treat cardiovascular and digestive system diseases, metformin can also upregulate heme oxygenase-1 expression. Therefore, we hypothesized that heme oxygenase-1 plays a significant role in mediating the beneficial effects of metformin on neuronal ferroptosis after spinal cord injury. To test this, we first performed a bioinformatics analysis based on the GEO database and found that heme oxygenase-1 was upregulated in the lesion of rats with spinal cord injury. Next, we confirmed this finding in a rat model of T9 spinal cord compression injury that exhibited spinal cord nerve cell ferroptosis. Continuous intraperitoneal injection of metformin for 14 days was found to both upregulate heme oxygenase-1 expression and reduce neuronal ferroptosis in rats with spinal cord injury. Subsequently, we used a lentivirus vector to knock down heme oxygenase-1 expression in the spinal cord, and found that this significantly reduced the effect of metformin on ferroptosis after spinal cord injury. Taken together, these findings suggest that metformin inhibits neuronal ferroptosis after spinal cord injury, and that this effect is partially dependent on upregulation of heme oxygenase-1.

Disrupting PIAS3-mediated SUMOylation of MLK3 ameliorates poststroke neuronal damage and deficits in cognitive and sensorimotor behaviors

Activated small ubiquitin-like modifiers (SUMOs) have been implicated in neuropathological processes following ischemic stroke. However, the target proteins of SUMOylation and their contribution to neuronal injury remain to be elucidated. MLK3 (mixed-lineage kinase 3), a member of the mitogen-activated protein kinase kinase kinase (MAPKKK) family, is a critical regulator of neuronal lesions following cerebral ischemia. Here, we found that SUMOylation of MLK3 increases in both global and focal ischemic rodent models and primary neuronal models of oxygen and glucose deprivation (OGD). SUMO1 conjugation at the Lys401 site of MLK3 promoted its activation, stimulated its downstream p38/c-Jun N-terminal kinase (JNK) cascades, and led to cell apoptosis. The interaction of MLK3 with PIAS3, a SUMO ligase, was elevated following ischemia and reperfusion. The PINIT domain of PIAS3 was involved in direct interactions with MLK3. Overexpression of the PINIT domain of PIAS3 disrupted the MLK3-PIAS3 interaction, inhibited SUMOylation of MLK3, suppressed downstream signaling, and reduced cell apoptosis and neurite damage. In rodent ischemic models, the overexpression of the PINIT domain reduced brain lesions and alleviated deficits in learning, memory, and sensorimotor functions. Our findings demonstrate that brain ischemia-induced MLK3 SUMOylation by PIAS3 is a potential target against poststroke neuronal lesions and behavioral impairments.

MLK3 localizes mainly to the cytoplasm and promotes oxidative stress injury via a positive feedback loop

Activation of mixed lineage kinase 3 (MLK3) by phosphorylation at Thr277/Ser281 stimulates downstream apoptotic pathways and ultimately leads to cell injury. MLK3 is reported to localize to both the cytoplasm and nucleus in human ovarian cancer cells and immortalized ovarian epithelial cells (T80 and T90 cells), and phosphorylation at Thr477 is required for the cytoplasmic retention of MLK3 in T80 cells. However, the subcellular distribution of MLK3 in other cell types has rarely been reported, and whether phosphorylation of MLK3 at Thr277/Ser281 affects its subcellular distribution is unknown. Here, our bioinformatics analysis predicted that MLK3 was mainly distributed in the cytoplasm and nucleus. In the human HEK293T embryonic kidney cell line and murine HT22 hippocampal neuronal cell line, endogenous MLK3 was more abundant in the cytoplasm and less abundant in the nucleus. In addition, overexpressed Myc-tagged MLK3 and EGFP-tagged MLK3 were also observed to localize mainly to the cytoplasm. MLK3 that was activated by phosphorylation at Thr277/Ser281 was mainly distributed in the cytoplasm, and phosphorylation deficient (T277A/S281A) and mimic (T277E/S281E) mutants both showed distributions similar to that of wild type (wt) MLK3, further proving that phosphorylation at Thr277/Ser281 was not involved in regulating MLK3 subcellular localization. In HEK293T cells, H2O2 stimulation accelerated MLK3 phosphorylation (activation), and this phosphorylation was reduced by the antioxidant N-acetylcysteine in a dose-dependent manner. Overexpressing wt MLK3 promoted the production of intracellular reactive oxygen species and increased cell apoptosis, both of which were enhanced by the phosphorylation-mimic (T277E/S281E) MLK3 variant but not by the phosphorylation-deficient (T277A/S281A) MLK3 variant. These findings provided additional evidence for the cytoplasmic and nuclear distribution of MLK3 in HEK293T cells or HT22 cells and revealed the pivotal role of MLK3 in the positive feedback loop of oxidative stress injury.

MicroRNA-137-mediated lysine demethylase 4A regulates the recovery of spinal cord injury via the SFRP4-Wnt/β-Catenin axis

OBJECTIVE

Spinal cord injury (SCI) causes great harm to the normal life of patients. Histone demethylase is involved in many biological processes, including SCI. Hence, this study explored the role and mechanism of histone lysine demethylase 4A (KDM4A) in SCI.

METHODS

The acute SCI (ASCI) rat model was established after spinal compression and the SCI neuronal model was induced via treating PC12 cells with lipopolysaccharide (LPS). KDM4A expression during SCI was detected. The microRNA (miRNA) targeting KDM4A was predicted and verified. The miRNA and KDM4A expression patterns were intervened in LPS-stimulated PC12 cells to evaluate their combined effects on neuronal cells in SCI. The downstream pathways of KDM4A were predicted, and SFRP4 and H3K9me3 expressions were determined. After the intervention of SFRP4 in LPS-treated cells, β-Catenin expression and the effect of SFRP4 on neuronal cells in SCI were detected. Finally, the effectiveness of the miR-137/KDM4A/SFRP4/Wnt/β-Catenin axis was verified in vivo.

RESULTS

KDM4A was abnormally elevated in SCI. miR-137 targeted KDM4A. miR-137 effectively inhibited the apoptosis of LPS-challenged PC12 cells, which could be reversed after overexpressing KDM4A. KDM4A promoted SFRP4 expression through demethylation of H3K9me3. Overexpression of SFRP4 blocked the Wnt/β-Catenin pathway and promoted apoptosis of LPS-stimulated cells. In vivo, miR-137 overexpression remarkably improved SCI symptoms, accompanied by obviously increased β-Catenin expression and notably decreased KDM4A and SFRP4 expressions, while overexpressed KDM4A treatment showed the opposite trend in the presence of miR-137.

CONCLUSION

We demonstrated that miR-137 targeted KDM4A and then downregulated SFRP4 to ameliorate SCI in a Wnt/β-Catenin-dependent manner.

Guan Xin Dan Shen formulation protects db/db mice against diabetic cardiomyopathy via activation of Nrf2 signaling

Guan Xin Dan Shen formulation (GXDSF) is a widely used treatment for the management of coronary heart disease in China and is composed of three primary components: Dalbergiae odoriferae Lignum, Salviae miltiorrhizae Radix et Rhizoma and Panax notoginseng Radix et Rhizoma. However, the potential use of GXDSF for the management of diabetic cardiomyopathy (DCM) has not been previously assessed. The present study aimed to assess the effects of GXDSF on DCM, as well as the underlying mechanism. In the present study, db/db mice were used. Following treatment with GXDSF for 10 weeks, fasting blood glucose, insulin sensitivity, serum lipid levels and cardiac enzyme levels were detected. Cardiac pathological alterations and cardiac function were assessed by performing hematoxylin and eosin staining and echocardiograms, respectively. TUNEL assays were conducted to assess cardiomyocyte apoptosis. Additionally, reverse transcription‑quantitative PCR and western blotting were performed to evaluate the expression of apoptosis‑associated genes and proteins, respectively. In the model group, the db/db mice displayed obesity, hyperlipidemia and hyperglycemia, accompanied by noticeable myocardial hypertrophy and diastolic dysfunction. Following treatment with GXDSF for 10 weeks, serum triglyceride levels were lower and insulin sensitivity was enhanced in db/db mice compared with the model group, which indicated improvement in condition. Cardiac hypertrophy and dysfunction were also improved in db/db mice following treatment with GXDSF, resulting in significantly increased left ventricular ejection fraction and fractional shortening compared with the model group. Following treatment with metformin or GXDSF, model‑induced increases in levels of myocardial enzymes were decreased in the moderate and high dose groups. Moreover, the results indicated that, compared with the model group, GXDSF significantly inhibited cardiomyocyte apoptosis in diabetic heart tissues by increasing Bcl‑2 expression and decreasing the expression levels of Bax, cleaved caspase‑3 and cleaved caspase‑9. Mechanistically, GXDSF enhanced Akt phosphorylation, which upregulated antioxidant enzymes mediated by nuclear factor erythroid 2‑related factor 2 (Nrf2) signaling. Collectively, the results of the present study indicated that GXDSF attenuated cardiac dysfunction and inhibited cardiomyocyte apoptosis in diabetic mice via activation of Akt/Nrf2 signaling. Therefore, GXDSF may serve as a potential therapeutic agent for the management of DCM.

EGCG treats ICH via up-regulating miR-137-3p and inhibiting Parthanatos

Intracranial hemorrhage (ICH) causes high mortality and disability without effective treatment in the clinical setting. (-)-Epigallocatechin-3-gallate (EGCG) exerts an essential role in the central nervous system and offers a promising therapeutic agent for the treatment of oxidative damage-related diseases. MiR-137 can inhibit the oxidative stress and apoptosis to attenuate neuronal injury. However, the role of EGCG in regulating miR-137-3p and neuronal Parthanatos remains to be unclear. In the present study, we build the ICH mice model to investigate the antioxidant effects of EGCG via upregulating miR-137-3p and inhibiting neuronal Parthanatos. We revealed that EGCG upregulated miR-137-3p and inhibited neuronal Parthanatos, and promoted the functional recovery, alleviated ICH-induced brain injury, and reduced oxidative stress in mice following ICH. However, following the inhibition of miR-137-3p and activation of Parthanatos, EGCG was unable to exert neuroprotective roles. These combined results suggest that EGCG may upregulate miR-137-3p and inhibit neuronal Parthanatos to accelerate functional recovery in mice after ICH, laying the foundation for EGCG to be a novel strategy for the treatment of neuronal injuries related to Parthanatos.

Melatonin Enhances Autophagy and Reduces Apoptosis to Promote Locomotor Recovery in Spinal Cord Injury via the PI3K/AKT/mTOR Signaling Pathway

Spinal cord injury (SCI) leads to neuronal death resulting in central nervous system (CNS) dysfunction; however, the pathogenesis is still poorly understood. Melatonin (MT), a hormone secreted mainly by the pineal gland, is associated with neuroprotective effects against SCI. Enhanced autophagy can promote the recovery of locomotor function and reduce apoptosis after SCI. Interestingly, MT increases autophagy in SCI in vivo. Nevertheless, the ability of MT to increase autophagy and decrease apoptosis, and the potential effects on the recovery of motor neurons in the anterior horn after SCI remain to be clarified. In this study, we discovered that MT treatment improved motor function recovery in a rat SCI model. Indeed, MT upregulated the expression of the phosphatidylinositol 3-kinase (PI3K), while expression of protein kinase B (AKT) and mammalian target of rapamycin (mTOR) was downregulated after SCI. Additionally, MT increased the expression of autophagy-activating proteins, while the expression of apoptosis-activating proteins in neurons was decreased following SCI. Furthermore, autophagy was inhibited, while apoptosis was induced in SCI model rats and lipopolysaccharide (LPS)-stimulated primary neurons by treatment with MT, the PI3K inhibitor 3-methyladenine (3-MA) and mTOR inhibitor Rapamycin (Rapa). Collectively, our results suggest that MT can improve the recovery of locomotor function by enhancing autophagy as well as reducing apoptosis after SCI in rats, probably via the PI3K/AKT/mTOR signaling pathway.

Bone mesenchymal stem cell-conditioned medium attenuates the effect of oxidative stress injury on NSCs by inhibiting the Notch1 signaling pathway

Numerous studies have demonstrated the therapeutic effect of bone mesenchymal stem cells on spinal cord injury (SCI), especially on neural stem cells (NSCs). However, the predominant mechanisms of bone mesenchymal stem cells (BMSCs) are unclear. Recently, some researchers have found that paracrine signaling plays a key role in the therapeutic capacity of BMSCs and emphasized that the protective effect of BMSCs may be due to paracrine factors. In this study, we aimed to investigate the potential mechanisms of BMSCs to protect NSCs. NSCs were identified by immunocytochemistry. The oxidative stress environment was simulated by H₂ O₂ (50, 100, 200 μM) for 2 h. The apoptotic rate of the NSCs was detected via flow cytometry. Lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) activity were evaluated via corresponding assay kits. Western blot was used to detect the expressions of Notch1, HES1, caspase-3, cleave caspase-3, Bax, and Bcl-2. We found that H₂ O₂ could significantly induce the apoptosis of NSCs, increase LDH, MDA levels, and decrease SOD activity by activating the Notch1 signaling pathway. DAPT (the specific blocker of Notch1) and BMSC-conditioned medium (BMSC-CM) could significantly prevent the apoptotic effect and oxidative stress injury on NSCs that were treated with H₂ O₂ . We also revealed that BMSC-CM could decrease the expression of Notch1, Hes1, cleave caspase-3, Bax, and increases the expression of Bcl-2 in NSCs, which was induced by H₂ O₂ . These results have revealed that BMSC-CM can neutralize the effect against oxidative stress injury on the apoptosis of NSCs by inhibiting the Notch1 signaling pathway.

Melatonin Enhances Autophagy and Reduces Apoptosis to Promote Locomotor Recovery in Spinal Cord Injury via the PI3K/AKT/mTOR Signaling Pathway

Spinal cord injury (SCI) leads to neuronal death resulting in central nervous system (CNS) dysfunction; however, the pathogenesis is still poorly understood. Melatonin (MT), a hormone secreted mainly by the pineal gland, is associated with neuroprotective effects against SCI. Enhanced autophagy can promote the recovery of locomotor function and reduce apoptosis after SCI. Interestingly, MT increases autophagy in SCI in vivo. Nevertheless, the ability of MT to increase autophagy and decrease apoptosis, and the potential effects on the recovery of motor neurons in the anterior horn after SCI remain to be clarified. In this study, we discovered that MT treatment improved motor function recovery in a rat SCI model. Indeed, MT upregulated the expression of the phosphatidylinositol 3-kinase (PI3K), while expression of protein kinase B (AKT) and mammalian target of rapamycin (mTOR) was downregulated after SCI. Additionally, MT increased the expression of autophagy-activating proteins, while the expression of apoptosis-activating proteins in neurons was decreased following SCI. Furthermore, autophagy was inhibited, while apoptosis was induced in SCI model rats and lipopolysaccharide (LPS)-stimulated primary neurons by treatment with MT, the PI3K inhibitor 3-methyladenine (3-MA) and mTOR inhibitor Rapamycin (Rapa). Collectively, our results suggest that MT can improve the recovery of locomotor function by enhancing autophagy as well as reducing apoptosis after SCI in rats, probably via the PI3K/AKT/mTOR signaling pathway.

Curcumin alleviates LPS-induced inflammation and oxidative stress in mouse microglial BV2 cells by targeting miR-137-3p/NeuroD1

Curcumin has been reported to exert protective effects on inflammation-related diseases, including spinal cord injury (SCI).

CD30 expression and survival in extranodal NK/T-cell lymphoma: a systematic review and meta-analysis

Background

The paradoxical reports about the prognostic value of the CD30 expression in extranodal NK/T-cell lymphoma (ENKTL) have restricted its further applications in clinical practice. To identify the common effects and the variation, we conducted this systematic review and meta-analysis.

Methods

PubMed, MEDLINE, Embase, and Web of Science were searched between January 1975 and 31 January 2017. The pooled hazard ratio was used to estimate the effect of the CD30 expression on overall survival. Bias was assessed by prespecified criteria referring to Reporting Recommendations for Tumor Marker Prognostic Studies and Newcastle-Ottawa Scale.

Results

Ten retrospective cohort studies with 310 patients are included. CD30 is associated with better overall survival significantly (HR 0.71, 95% CI 0.51 to 0.99, I² = 0%). A greater effect is observed among studies including participants predominant in regional involvement (HR 0.31, 95%CI 0.13 to 0.76, I² = 0%) compared with those in systemic involvement.

Conclusions

This study indicates that the CD30 expression is significantly associated with better prognosis in ENKTL, especially for patients with regional lymphoma involvement.

Electroacupuncture Restores Locomotor Functions After Mouse Spinal Cord Injury in Correlation With Reduction of PTEN and p53 Expression

Background: We previously showed that electroacupuncture (EA) at Jiaji points promotes expression of adhesion molecule L1 in spinal cord tissue after mouse spinal cord injury (SCI) and contributes to recovery of neural functions. Objective: We investigated the effects of EA on downstream signaling molecules of L1 and molecules relevant to apoptosis with the aim to understand the underlying molecular mechanisms. Methods: Female C57BL/6 mice were divided into a sham group, injury group, injury+acupuncture (AP) group and injury+EA group. We investigated the changes in cognate L1-triggered signaling molecules after SCI by immunofluorescence staining and immunoblot analysis. Results: Protein levels of phosphatase and tensin homolog (PTEN) and p53 were decreased by EA at different time points after injury, whereas the levels of phosphorylated mammalian target of rapamycin (pmTOR), p-Akt and phosphorylated extracellular signal-regulatedkinase (p-Erk) were increased. Also, levels of myelin basic protein (MBP) were increased by EA. AP alone showed less pronounced changes in expression of the investigated molecules, when compared to EA. Conclusion: We propose that EA contributes to neuroprotection by inhibiting PTEN and p53 expression and by increasing the levels of pmTOR/Akt/Erk and of MBP after SCI. These observations allow novel insights into the beneficial effects of EA via L1-triggered signaling molecules after injury.

The microglial activation profile and associated factors after experimental spinal cord injury in rats

BACKGROUND

Spinal cord injury (SCI) has imposed a great impact on the quality of life of patients due to its relatively young age of onset. The pathophysiology of SCI has been proven to be complicated. Microglia plays an important role in neuroinflammation and second injuries after SCI. Different environment and other factors may determine the microglial activation profile and what role they play. However, neither accurate time-course profiles of microglial activation nor influence factors have been demonstrated in varied SCI models.

METHODS

A rat compressive SCI model was used. Microglial activation profile and contents of inflammatory factors including IL-1β, IL-6 and TNF-α were detected. Myelination status as well as levels of iron and glutamate concentration, adenosine triphosphate (ATP) and potassium are also assessed.

RESULTS

Our results showed that the activated microglia participating in immune-mediated responses peaked at day 7 post SCI and gradually decreased during the following 3 weeks. Contrarily, myelination and oligodendroglia showed an opposite trend, indicating that microglia may be a key factor partly through inflammatory reaction. Iron and glutamate concentration were found to be the highest at day 7 after SCI while both ATP and potassium reached a low valley at the same time.

CONCLUSION

These findings showed a microglial activation profile and the alterations of associated factors after experiment SCI model. Moreover, our data suggest that high iron and glutamate concentration may be released by damaged oligodendroglia and contribute to the activation of microglial after SCI.

MiR-137 inhibited inflammatory response and apoptosis after spinal cord injury via targeting of MK2

Spinal cord injuries are common and troublesome disorder, which is mediated by various signal pathways and mechanisms. MK2 is also involved in numerous inflammatory diseases including spinal cord injury. The role of microRNA-137 (miR-137) and its detailed working mechanism in spinal cord injuries remain unclear. In the present study, we found that an elevated MK2 but a decreased miR-137 was expressed in serum specimens of patients with spinal cord injury and in hydrogen peroxide-treated C8-D1A and C8-B4 cells. Meanwhile, we suggested that upregulation of miR-137 could inhibit the expression of TNF-α and IL-6, two markers of inflammatory response after SCI, and apoptosis in hydrogen peroxide-treated C8-D1A and C8-B4 cells. Furthermore, we verified that MK2 was a direct target of miR-137 thorough a constructed luciferase assay. Even further, we elucidated that miR-137 could suppress the inflammatory response and apoptosis via negative regulation of MK2. Finally, through an animal model trial performed using mice, we demonstrated the protective effect of how miR-137 works on inflammatory response and apoptosis after spinal cord injury. Considering all the forementioned, our findings revealed that miR-137 inhibited inflammatory response and apoptosis after spinal cord injury via the targeting of MK2. The outcomes of the present study might indicate a new target in molecular treatment of SCI.

A plasma mir-125a-5p as a novel biomarker for Kawasaki disease and induces apoptosis in HUVECs

Background

Kawasaki disease (KD) is a childhood systemic vasculitis that exhibits a specific preference for the coronary arteries. The aetiology remains unknown and there are no especially diagnostic tests. microRNAs (miRNAs) are 18 to 23 nucleotides non-coding RNAs that are negative regulator of gene expression and play a crucial role in the regulatory network of the genome. Recently, circulating miRNAs have been found presentation in human plasma and displayed some characteristics of the ideal biomarker. However, few researches explored differentially expressed miRNAs in the plasma of KD patients. Our study is to identify circulating miRNAs in KD plasma which can serve as potential biomarkers of KD diagnosis.

Materials and methods

The total of five pairs of acute KD and normal plasma samples were analyzed using ABI miRNAs TLDA Assay chip. Differentially expression of miR-125a-5p in plasma were confirmed by quantitative real-time PCR (qRT-PCR) in independent cohort (acute KD = 30, convalescent KD = 30 and healthy control = 32). After bioinformatics prediction, miR-125a-5p vector and inhibitor were transfected into HUVECs respectively, to observe MKK7 expression as a potential target gene. Flow cytometry was used to analyze apoptosis. The mRNA and protein levels of desired genes including MKK7, Caspase-3, Bax and Bcl2 were detected by qRT-PCR and western blotting.

Results

Eighteen miRNAs were differentially expressed in acute KD’s plasma compared with healthy control. miR-125a-5p was significantly increased in plasma of KD patients (p = 0.000), but no variation between acute and convalescent KD (p = 0.357). Moreover, the results from the gain and loss functions of miR-125a-5p in HUVECs have shown that miR-125a-5p remarkably suppressed MKK7 expression, as a novel target gene. Importantly, miR-125a-5p also induced apoptosis in HUVECs through inhibition MKK7 levels to regulate Bax/Bcl2 pathway resulting to activate Caspase-3.

Conclusion

Our study indicated that the circulating miR-125a-5p levels in KD’s plasma have remarkably evaluated compared with healthy individuals. miR-125a-5p might play a role in the development of KD by regulating target gene MKK7 to induce apoptosis in vascular endothelial cells. Therefore, our findings have suggested that detected miR-125a-5p levels in plasma could be used as a potential biomarker in early KD diagnosis.

Myosin IIA-related Actomyosin Contractility Mediates Oxidative Stress-induced Neuronal Apoptosis

Oxidative stress-induced neuronal apoptosis plays an important role in the progression of central nervous system (CNS) diseases. In our study, when neuronal cells were exposed to hydrogen peroxide (H₂O₂), an exogenous oxidant, cell apoptosis was observed with typical morphological changes including membrane blebbing, neurite retraction and cell contraction. The actomyosin system is considered to be responsible for the morphological changes, but how exactly it regulates oxidative stress-induced neuronal apoptosis and the distinctive functions of different myosin II isoforms remain unclear. We demonstrate that myosin IIA was required for neuronal contraction, while myosin IIB was required for neuronal outgrowth in normal conditions. During H₂O₂-induced neuronal apoptosis, myosin IIA, rather than IIB, interacted with actin filaments to generate contractile forces that lead to morphological changes. Moreover, myosin IIA knockout using clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease (CRISPR/Cas9) reduced H₂O₂-induced neuronal apoptosis and the associated morphological changes. We further demonstrate that caspase-3/Rho-associated kinase 1 (ROCK1) dependent phosphorylation of myosin light chain (MLC) was required for the formation of the myosin IIA-actin complex. Meanwhile, either inhibition of myosin II ATPase with blebbistatin or knockdown of myosin IIA with siRNA reversely attenuated caspase-3 activation, suggesting a positive feedback loop during oxidative stress-induced apoptosis. Based on our observation, myosin IIA-actin complex contributes to actomyosin contractility and is associated with the positive feedback loop of caspase-3/ROCK1/MLC pathway. This study unravels the biochemical and mechanistic mechanisms during oxidative stress-induced neuronal apoptosis and may be applicable for the development of therapies for CNS diseases.