Silencing of the MEKK2/MEKK3 Pathway Protects against Spinal Cord Injury via the Hedgehog Pathway and the JNK Pathway

Tanshinone IIA protects motor neuron-like NSC-34 cells against lipopolysaccharide-induced cell injury by the regulation of the lncRNA TCTN2/miR-125a-5p/DUSP1 axis

Background

Tanshinone IIA (TSIIA) exerts a protective role in spinal cord injury (SCI). However, the mechanism of TSIIA activity in SCI remains to be elucidated.

Methods

Cell viability and apoptosis were gauged by CCK-8 assay and flow cytometry, respectively. The expression levels of lncRNA TCTN2, miR-125a-5p and DUSP1 were detected by qRT-PCR and western blot. Direct relationship between miR-125a-5p and TCTN2 or DUSP1 was verified by dual-luciferase reporter assay.

Results

In mouse NSC-34 cells, LPS reduced the expression of TCTN2. TSIIA alleviated cell injury induced by LPS and increased TCTN2 expression in LPS-exposed NSC-34 cells. TCTN2 was a downstream mediator of TSIIA activity. TCTN2 targeted miR-125a-5p, and TCTN2 over-expression attenuated LPS-induced cell damage in NSC-34 cells by down-regulating miR-125a-5p. TCTN2 functioned as a post-transcriptional regulator of DUSP1 expression through miR-125a-5p. DUSP1 was a functional target of miR-125a-5p in controlling NSC-34 cell injury induced by LPS. TSIIA inhibited miR-125a-5p expression and increased the level of DUSP1 protein in LPS-exposed NSC-34 cells.

Conclusion

Our study establishes a novel mechanism, the TCTN2/miR-125a-5p/DUSP1 axis, at least in part, for the protective activity of TSIIA in cell injury induced by LPS.

MDMA targets miR-124/MEKK3 via MALAT1 to promote Parkinson's disease progression

BACKGROUND

Parkinson's disease (PD) is a well-known neurodegenerative disease that is usually caused by the progressive loss of dopamine neurons and the formation of Lewy vesicles. 3,4-Methylenedioxymethamphetamine (MDMA) has been reported to cause damage to human substantia nigra neurons and an increased risk of PD, but the exact molecular mechanisms need further investigation.

METHODS

MPTP- and MPP+-induced PD cells and animal models were treated with Nissl staining to assess neuronal damage in the substantia nigra (SN) area; immunohistochemistry to detect TH expression in the SN; TUNEL staining to detect apoptosis in the SN area; Western blotting to detect the inflammatory factors NF-κB, TNF-α, IL-6 and mitogen-activated protein kinase kinase kinase 3 (MEKK3); Griess assay for NO; RT‒qPCR for metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and miR-124 expression; Cell proliferation was assessed by CCK-8. Dual luciferase reporter genes were used to verify targeting relationships.

RESULTS

MDMA promoted MALAT1 expression, and knockdown of MALAT1 alleviated the MDMA-induced inhibition of SH-SY5Y cell proliferation, inflammation, NO release, SN neuronal injury, and TH expression inhibition. Both inhibition of miR-124 and overexpression of MEKK3 reversed the neuroprotective effects exhibited by knockdown of MALAT1.

CONCLUSION

MDMA promotes MALAT1 expression and inhibits the targeted downregulation of MEKK3 by miR-124, resulting in upregulation of the expression of MEKK3 and finally jointly promoting PD progression.

Bestrophin3 Deficiency in Vascular Smooth Muscle Cells Activates MEKK2/3-MAPK Signaling to Trigger Spontaneous Aortic Dissection

BACKGROUND

Aortic dissection (AD) is a fatal cardiovascular disorder without effective medications due to unclear pathogenic mechanisms. Bestrophin3 (Best3), the predominant isoform of bestrophin family in vessels, has emerged as critical for vascular pathological processes. However, the contribution of Best3 to vascular diseases remains elusive.

METHODS

Smooth muscle cell-specific and endothelial cell-specific Best3 knockout mice (Best3SMKO and Best3ECKO, respectively) were engineered to investigate the role of Best3 in vascular pathophysiology. Functional studies, single-cell RNA sequencing, proteomics analysis, and coimmunoprecipitation coupled with mass spectrometry were performed to evaluate the function of Best3 in vessels.

RESULTS

Best3 expression in aortas of human AD samples and mouse AD models was decreased. Best3SMKO but not Best3ECKO mice spontaneously developed AD with age, and the incidence reached 48% at 72 weeks of age. Reanalysis of single-cell transcriptome data revealed that reduction of fibromyocytes, a fibroblast-like smooth muscle cell cluster, was a typical feature of human ascending AD and aneurysm. Consistently, Best3 deficiency in smooth muscle cells decreased the number of fibromyocytes. Mechanistically, Best3 interacted with both MEKK2 and MEKK3, and this interaction inhibited phosphorylation of MEKK2 at serine153 and MEKK3 at serine61. Best3 deficiency induced phosphorylation-dependent inhibition of ubiquitination and protein turnover of MEKK2/3, thereby activating the downstream mitogen-activated protein kinase signaling cascade. Furthermore, restoration of Best3 or inhibition of MEKK2/3 prevented AD progression in angiotensin II-infused Best3SMKO and ApoE-/- mice.

CONCLUSIONS

These findings unveil a critical role of Best3 in regulating smooth muscle cell phenotypic switch and aortic structural integrity through controlling MEKK2/3 degradation. Best3-MEKK2/3 signaling represents a novel therapeutic target for AD.

MicroRNAs in septic acute kidney injury

Sepsis is a potentially fatal complication of burns and trauma that can cause acute kidney injury (AKI) with substantial morbidity and mortality, but this disease is poorly understood. Despite medical advances, effective therapeutic regimens for septic AKI remain uncommon. MicroRNAs (miRNAs) are endogenous non-coding RNAs that influence the translation of target messenger RNAs in a variety of biological processes. Emerging evidence has shown that miRNAs are intimately associated with septic AKI. The goal of this review was to summarize recent advances in the profound understanding of the functional role of miRNAs in septic AKI, as well as to provide new insights into miRNAs as feasible biomarkers and therapeutic targets for septic AKI.

Acupuncture combined with moxibustion promote the recovery of spinal cord injury in correlation with Shh/Gli-1 signaling pathway

Objective: Acupuncture combined with moxibustion (AM) therapy has been applied to treat spinal cord injury (SCI), but the underlying mechanism is unclear. The present study aimed to confirm the effect and mechanism of AM treatment on the recovery of SCI.Design: Male Sprague-Dawley rats were used to establish the SCI model by impact method. SCI rat models were subjected to AM treatment at Dazhui (GV14) and Jiaji points (T7-T12), Yaoyangguan (GV3), Zusanli (ST36) and Ciliao (BL32).Outcome measures: Motor function and cell apoptosis in rats after SCI. The mRNA and protein expression levels of Shh and Gli-1 were determined by real-time quantitative polymerase chain reaction, western blot and immunohistochemistry.Results: After AM treatment, the hindlimb motor function of SCI rats was significantly increased than the SCI group at 7, 9, 11, 14 days (P < 0.05). AM treatment 7 d and 14 d significantly preserved the nissl-stained positive neurons and significantly decreased number of apoptotic cells, compared to that of SCI 7 and 14 d groups (P < 0.05). AM treatment improved the mRNA protein levels of Shh and Gli-1 after 7 and 14 days treatment compared to the SCI group (P < 0.05).Conclusion: AM could improve the expression of Shh and Gli-1 in injured spinal cord of rats. That could be part of underlying mechanisms of AM treatment including recover motor function and preserve the neuron cells and alleviate the apoptosis of nerve cells in rats after SCI.

An extracellular matrix damage sensor signals through membrane-associated kinase DRL-1 to mediate cytoprotective responses in Caenorhabditis elegans

We and others previously identified circumferential bands of collagen named annular furrows as key components of a damage sensor in the cuticle of Caenorhabditis elegans that regulates cytoprotective genes. Mutation or loss of non-collagen secreted proteins OSM-7, OSM-8, and OSM-11 activate the same cytoprotective responses without obvious changes to the cuticle indicating that other extracellular proteins are involved. Here, we used RNAi screening to identify protein kinase DRL-1 as a key modulator of cytoprotective gene expression and stress resistance in furrow and extracellular OSM protein mutants. DRL-1 functions downstream from furrow disruption and is expressed in cells that induce cytoprotective genes. DRL-1 is not required for expression of cytoprotective genes under basal or oxidative stress conditions consistent with specificity to extracellular signals. DRL-1 was previously shown to regulate longevity via a 'Dietary Restriction-Like' state, but it functions downstream from furrow disruption by a distinct mechanism. The kinase domain of DRL-1 is related to mammalian MEKK3, and MEKK3 is recruited to a plasma membrane osmosensor complex by a scaffold protein. In C. elegans, DRL-1 contains an atypical hydrophobic C-terminus with predicted transmembrane domains and is constitutively expressed at or near the plasma membrane where it could function to receive extracellular damage signals for cells that mount cytoprotective responses.

Repair of spinal cord injury in rats via exosomes from bone mesenchymal stem cells requires sonic hedgehog

Objective

The loss of neural ability leading to subsequent diminishing of motor function and the impairment below the location of the injury is a result of the SCI (Spinal Cord Injury). Among the many therapeutic agents for SCI, the exosomes considered as extracellular vesicles seem to be the most promising. Sonic Hedgehog (Shh) is an exosome-carrying protein. This Study's purpose was to identify whether Shh is required for exosomes from BMSCs (mesenchymal stem cells of the bone) and plays a protective effect on SCI.

Methods

Spinal cord injection with shRNA Shh-adeno associated virus (sh-Shh-AAV) were used to silence Shh. Exosomes were extracted from BMSCs. Rats that had suffered SCI were given intravenous injections of exosomes through the veins of the tail. Immunohistochemistry was used to identify the expression of Shh glycoprotein molecule as well as the expression of Gli-1 (glioma-associated oncogene homolog 1) in the rat spinal cord tissues. Western blot was performed to measure the levels of growth associated protein-43 (GAP-43). The BBB (Basso Beattie Bresnahan) score was used to assess the motor functions of the hind legs. In the same manner, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling or TUNEL and Nissl Staining was deployed to assess the level of regeneration of neurons and assess the level of histopathological damage in the tissues of the Spinal Cord.

Results

In the case of the rats with SCI, the levels of display of Gli-1 and Shh showed dramatic improvement after the BMSCs exosome injections. In comparison to rats with SCI, the subjects of BMSCs exosomes group showed an improvement in their SCI, including a higher BBB score and Nissl body count, increasing GAP-43 expression, along with a much-decreased number of cells that suffered apoptosis. While the exosome effect on Spinal Cord Injury was completely ineffective in rats that had Shh silencing.

Conclusions

Exosomes secreted from BMSCs showed great effectiveness in the SCI healing with a vital involvement of Shh in this repair.

Exosomes secreted from sonic hedgehog-modified bone mesenchymal stem cells facilitate the repair of rat spinal cord injuries

BACKGROUND

Spinal cord injuries (SCIs) can cause a loss of neurons and associated sensory and motor functionality below the injured site. No approaches to treating SCIs in humans have been developed to date. Exosomes are extracellular vesicles that hold promise as a potential therapeutic modality when treating such injuries. The present study was thus designed to determine whether sonic hedgehog (Shh)-overexpressing bone mesenchymal stem cell (BMSC)-derived exosomes were protective in the context of SCIs.

METHODS

Exosomes were extracted from control or Shh lentivirus-transduced BMSCs, yielding respective BMSC-Exo and BMSC-Shh-Exo preparations which were intravenously injected into SCI model rats. Shh expression in spinal cord tissues in these animals was then assessed via immunohistochemical staining, while Basso-Beattie-Bresnahan (BBB) scores were utilized to measure high limb motor function. Neuronal damage and regeneration within the spinal cord were additionally evaluated via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Nissl, hematoxylin and eosin, and immunofluorescent staining.

RESULTS

Both BMSC-Exo and BMSC-Shh-Exo preparations significantly increased Shh expression in the spinal cord of SCI model rats and improved BBB scores in these treated animals, while also increasing the frequencies of Nissl- and NeuN-positive neurons are reducing the numbers of apoptotic and GFAP-positive neurons. While both treatments yielded some degree of benefit to treated animals relative to untreated controls, BMSC-Shh-Exos were more beneficial than were control BMSC-Exos.

CONCLUSIONS

Shh-overexpressing BMSC-derived exosomes represent an effective treatment that can facilitate SCI repair in rats.

MiR-150-5p protects against septic acute kidney injury via repressing the MEKK3/JNK pathway

BACKGROUND

Septic acute kidney injury (AKI) is associated with increased morbidity and mortality in critically ill patients. MicroRNA is reportedly involved in sepsis-induced organ dysfunction, while the role of miR-150 in septic AKI remains ambiguous.

METHODS

Quantitative real-time PCR (qRT-PCR) was carried out to examine miR-150-5p expression in both septic AKI patients and volunteers without septic AKI. Lipopolysaccharide (LPS) was used to treat renal tubular epithelial cell line HK-2 and C57/BL6 mice to establish in vitro and in vivo sepsis-induced AKI models. Cell apoptosis was determined using TdT-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry. Cell viability was tested using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Renal pathological changes were examined via Hematoxylin-Eosin (H&E) staining, and renal function was measured via blood urea nitrogen (BUN) and creatinine (Cre) measurements. The MEKK3/JNK profile and oxidative stress markers (including COX2 and iNOS) were examined by immunoblot analysis, and the expression levels of inflammatory cytokines (TNF-α, IL-6, and IL-1β) and oxidative stress markers (MDA, SOD, and CAT) were evaluated by ELISA.

RESULTS

MiR-150-5p was down-regulated in the serum of patients with septic AKI (compared to healthy volunteers). Moreover, miR-150-5p levels were lower in LPS-treated HK-2 cell lines and in the septic AKI mouse model. Additionally, Stat-3 activation mediated the decrease of miR-150-5p. Functionally, miR-150-5p agomir attenuated LPS-induced apoptosis in HK-2 cells, in addition to renal inflammatory responses and oxidative stress. In contrast, inhibition of miR-150-5p aggravated LPS-induced apoptosis, inflammatory reactions and oxidative stress. Furthermore, miR-150-5p agomir decreased BUN and Scr levels in the septic AKI mice model repressed TNF-α, IL-6 and IL-1β, and up-regulated SOD and CAT down-regulated MDA in the kidney tissues. Moreover, miR-150-5p was identified as a target gene for Stat3, and the overexpression of Stat3 partially promoted the effect of down-regulating miR-150-5p on LPS-induced HK2 cell injury. Mechanistically, the MEKK3/JNK pathway was identified as a functional target of miR-150-5p, and the knockdown of MEKK3 showed protective effects against LPS mediated HK-2 cell apoptosis.

CONCLUSION

Stat3-mediated miR-150-5p exerted protective effects in sepsis-induced acute kidney injury by regulating the MEKK3/JNK pathway.

Allicin regulates Treg/Th17 balance in mice with collagen-induced arthritis by increasing the expression of MEKK2 protein

To study the role of Allicin in regulating Treg/Th17 ratio in splenic lymphocyte by increasing the expression of MEKK2 protein in MAPK signaling pathway, and to explore the mechanism of immune response in mice with collagen-induced arthritis (CIA). Mouse CIA model was induced by chicken collagen type II, and experimental mice were randomly divided into NC group, Model group, and Allicin group. HE staining was used to compare the degree of joint pathological damage in mice of each group, and Masson staining to observe the proliferation of collagen tissue in each group. Flow cytometry detected Treg/Th17 ratio in splenic lymphocytes. Furthermore, RT-PCR and WB were used to detect the mRNA and protein expression of related transcription factors and inflammatory factors Foxp3, ROR-γt, and IL-17A, as well as MEK2 protein expression in splenic lymphocytes. The results showed that Allicin treatment could reduce the severity of arthritis and the proliferation of collagen fibers on the surface of cartilage and bone joints in CIA mice. Compared with NC group, Treg decreased and Th17 increased in spleen lymphocyte of Model group (p < .01); after Allicin treatment, Treg increased while Th17 decreased significantly (p < .01). Meanwhile, MEKK2 protein expression in spleen lymphocyte of Model group decreased compared to that in NC group (p < .01), and MEK2 protein expression increased significantly after Allicin treatment (p < .01). To sum up, the present study suggests that MEKK2 protein plays an important role in the pathogenesis of CIA model. In terms of mechanism, Allicin may play a therapeutic role in rheumatoid arthritis (RA) by increasing the expression of MEKK2 protein and affecting Treg/Th17 ratio.

Deubiquitinase USP18 regulates reactive astrogliosis by stabilizing SOX9

Reactive astrogliosis is a pathological feature of spinal cord injury (SCI). The ubiquitin-proteasome system plays a crucial role in maintaining protein homeostasis and has been widely studied in neuroscience. Little, however, is known about the underlying function of deubiquitinating enzymes in reactive astrogliosis following SCI. Here, we found that ubiquitin-specific protease 18 (USP18) was significantly upregulated in astrocytes following scratch injury, and in the injured spinal cord in mice. Knockdown of USP18 in vitro and conditional knockout of USP18 in astrocytes (USP18 CKO) in vivo significantly attenuated reactive astrogliosis. In mice, this led to widespread inflammation and poor functional recovery following SCI. In contrast, overexpression of USP18 in mice injected with adeno-associated virus (AAV)-USP18 had beneficial effects following SCI. We showed that USP18 binds, deubiquitinates, and thus, stabilizes SRY-box transcription factor 9 (SOX9), thereby regulating reactive astrogliosis. We also showed that the Hedgehog (Hh) signaling pathway induces expression of USP18 through Gli2-mediated transcriptional activation after SCI. Administration of the Hh pathway activator SAG significantly increased reactive astrogliosis, reduced lesion area and promoted functional recovery in mice following SCI. Our results demonstrate that USP18 positively regulates reactive astrogliosis by stabilizing SOX9 and identify USP18 as a promising target for the treatment of SCI.

MiR-132-3p Modulates MEKK3-Dependent NF-κB and p38/JNK Signaling Pathways to Alleviate Spinal Cord Ischemia-Reperfusion Injury by Hindering M1 Polarization of Macrophages

Spinal cord ischemia-reperfusion (SCIR) injury is a serious complication of open surgical and endovascular aortic procedures. MicroRNA-132-3p (miR-132-3p) has been reported to be involved in the progression of various diseases, but its role in SCIR injury is unclear. Thus, we aimed in this study to investigate the mechanism of miR-132-3p in SCIR injury and explore its pathway as a therapeutic target for SCIR injury. We first constructed a SCIR injury rat model and documented motor function in the model. Reverse transcription quantitative polymerase chain reaction (RT-qPC)R and Western blot analysis were used to detect the expression of miR-132-3p and mitogen-activated protein kinase kinase kinase 3 (MEKK3) in SCIR injury rats. The interaction between miR-132-3p and MEKK3 was identified by dual-luciferase reporter gene assay. Then, the effects of miR-132-3p and MEKK3 on macrophage M1 polarization were evaluated in vitro and in vivo by altering their expression in macrophages of SCIR injury rats, with treatments altering the nuclear factor-kappaB (NF-κB) and c-Jun N-terminal kinase (JNK)/p38 signaling pathways using SP600125, SB203580, or PDTC. The SCIR injury rats had a high Tarlov score and low miR-132-3p expression along with high MEKK3 expression. miR-132-3p could directly bind to MEKK3, and that macrophage M1 polarization and inflammation could be inhibited by overexpression of miR-132-3p through downregulating MEKK3 and inactivating the NF-κB and p38/JNK signaling pathways. Besides, increased miR-132-3p expression could decrease the injured rat Tarlov score. Overall, our study demonstrated that miR-132-3p can suppress M1 polarization of macrophages and alleviate SCIR injury by blocking the MEKK3-dependent activation of the NF-κB and p38/JNK signaling pathway. Thus, miR-132-3p and its downstream pathways may be useful targets to alleviate the symptoms of SCIR injury.

Hedgehog signaling promotes sorafenib resistance in hepatocellular carcinoma patient-derived organoids

BACKGROUND

The mechanism underlying sorafenib resistance in hepatocellular carcinoma (HCC) remains unclear. Accumulating evidence suggests that tumor-initiating cells (TICs) are a pivotal driving force. Both CD44 and Hedgehog signaling play crucial roles in TIC properties in HCC. In this study, we explored the roles of CD44 and Hedgehog signaling in sorafenib resistance and evaluated the therapeutic effect of cotreatment with sorafenib and Hedgehog signaling inhibitors in HCC patient-derived organoid (PDO) models to improve treatment efficacy.

METHODS

We collected HCC specimens to establish PDO models. Cell viability and malignant transformation properties were investigated after treatment with different TIC-related inhibitors alone or in combination with sorafenib to evaluate the therapeutic effect in PDOs and cell lines by in vitro and in vivo experiments. Expression levels of Hedgehog signaling proteins and CD44 were monitored to reveal potential relationships.

RESULTS

We demonstrated that our HCC PDO models strongly maintained the histological features of the corresponding tumors and responded to drug treatment. Furthermore, CD44-positive HCC PDOs were obviously resistant to sorafenib, and sorafenib increased CD44 levels. A drug screen showed that compared with Notch, Hippo and Wnt signaling inhibitors, a Hedgehog signaling inhibitor (GANT61) potently suppressed HCC PDO cell viability. In addition, there was a highly synergistic effect in vitro and in vivo on the suppression of cell viability and malignant properties when sorafenib and GANT61 were added to CD44-positive HCC PDOs and cell lines, respectively. Furthermore, the upregulation of CD44 and Hedgehog signaling induced by sorafenib was reversed by GANT61.

CONCLUSIONS

GANT61 significantly suppressed Hedgehog signaling to reverse sorafenib resistance in CD44-positive HCC. The combination of sorafenib and Hedgehog signaling inhibitors might be effective in HCC patients with high CD44 levels as a personalized-medicine approach.