Triptolide improves spinal cord injury by promoting autophagy and inhibiting apoptosis

Pyroptosis, ferroptosis, and autophagy in spinal cord injury: regulatory mechanisms and therapeutic targets

Regulated cell death is a form of cell death that is actively controlled by biomolecules. Several studies have shown that regulated cell death plays a key role after spinal cord injury. Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords. Autophagy, a complex form of cell death that is interconnected with various regulated cell death mechanisms, has garnered significant attention in the study of spinal cord injury. This injury triggers not only cell death but also cellular survival responses. Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis, ferroptosis, and autophagy. Therefore, this review aims to comprehensively examine the mechanisms underlying regulated cell deaths, the signaling pathways that modulate these mechanisms, and the potential therapeutic targets for spinal cord injury. Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury. Moreover, a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.

Impaired autophagy-mediated macrophage polarization contributes to age-related hyposalivation

Age-related dysfunction of salivary glands (SGs) leading to xerostomia or dry mouth is typically associated with increased dental caries and difficulties in mastication, deglutition or speech. Inflammaging-induced hyposalivation plays a significant role in aged SGs; however, the mechanisms by which ageing shapes the inflammatory microenvironment of SGs remain unclear. Here, we show that reduced salivary secretion flow rate in aged human and mice SGs is associated with impaired autophagy and increased M1 polarization of macrophages. Our study reveals the crucial roles of SIRT6 in regulating macrophage autophagy and polarization through the PI3K/AKT/mTOR pathway, as demonstrated by generating two conditional knock out mice. Furthermore, triptolide (TP) effectively rejuvenates macrophage autophagy and polarization via targeting this pathway. We also design a local delivery of TP-loaded apoptotic extracellular vesicles (ApoEVs) to improve age-related SGs dysfunction therapeutically. Collectively, our findings uncover a previously unknown link between SIRT6-regulated autophagy and macrophage polarization in age-mediated hyposalivation, while our locally therapeutic strategy exhibits potential preventive effects for age-related hyposalivation.

Piperine attenuates cancer-associated pain induced by microglial activation via increasing miR-150-50p

AIM

Severe painful neuropathy often occurs in cancer patients receiving chemotherapy. Emerging evidence has demonstrated that microglia contribute to the occurrence and development of cancer-associated pain. This study aimed to investigate the mechanisms by which piperine influences cancer-associated pain induced by microglia activation.

METHODS

The tumor cell implantation (TCI) model was adopted as the cancer-associated pain model in mice. Behavioral tests were done to confirm that model mice were sensitive to acute mechanical and thermal pain. Western blot (WB) and immunofluorescence (IF) were conducted to quantify expression level of microglia marker protein Iba1 in mice spinal cord tissues. The expression of miR-150-5p and CXCL12 in the mice spinal cord was evaluated by Quantitative real-time Polymerase Chain Reaction (qRT-PCR) and fluorescence in situ hybridization (FISH). Primary microglia from mice were treated with lipopolysaccharide (LPS) to investigate neuroinflammation.

RESULTS

The modeled mice showed high susceptibility to acute mechanical hyperalgesia and thermal hyperalgesia. The expression of microglia marker protein Iba1 in the model group was increased in vitro and in vivo. Treatment with piperine effectively relieved the cancer-associated pain in mice. The results of FISH and qRT-PCR showed that piperine significantly increased the expression of miR-150-5p and reduced the expression of CXCL12 in the spinal cord of mice. Furthermore, it inhibited the microglia-induced cancer-associated pain.

CONCLUSIONS

Piperine upregulates miR-150-50p levels, inhibits CXCL12 expression, and reduces microglia levels at the lesion site. Therefore, piperine may be a potential drug candidate for the treatment of cancer-associated pain.

Icariin promotes functional recovery in rats after spinal cord injury by inhibiting YAP and regulating PPM1B ubiquitination to inhibiting the activation of reactive astrocytes

Objective

The limited ability to regenerate axons after spinal cord injury (SCI) is influenced by factors such as astrocyte activation, reactive proliferation, and glial scar formation. The TGF-β/Smad (transforming growth factor-β/mothers against decapentaplegic homolog) pathway, associated with astrocytic scarring, plays a crucial role in recovery post-injury. This study aims to investigate how icariin (ICA) interacts with reactive astrocytes in the treatment of spinal cord injury.

Methods

A rat SCI model was constructed, and the recovery of motor function was observed after treatment with ICA.HE staining, LFB staining, immunofluorescence staining, and Western blotting were employed to assess ICA's ability to inhibit astrocyte proliferation in rats following spinal cord injury by modulating YAP, as well as to evaluate the reparative effects of ICA on the injured spinal cord tissue. Primary astrocytes were isolated and cultured. Immunoprecipitation-Western Blot (IP-WB) ubiquitination and cytoplasm-nuclear separation were employed to assess PPM1B ubiquitination and nuclear translocation.

Results

The CatWalk XT gait analysis, BBB (Basso, Beattie, and Bresnahan) score, electrophysiological measurements, HE staining, and LFB staining collectively demonstrated that ICA promotes motor function and tissue recovery following spinal cord injury in rats. Immunofluorescence staining and Western Blot analyses revealed that ICA inhibits astrocyte proliferation in rats post-spinal cord injury by suppressing YAP activity. Furthermore, the activation of YAP by XMU-MP-1 was shown to compromise the efficacy of ICA in these rats after spinal cord injury. Additional immunofluorescence staining and Western Blot experiments confirmed that ICA inhibits TGFβ1-induced astrocyte activation through the regulation of YAP. The knockdown of PPM1B (protein phosphatase, Mg2+/Mn2+-dependent 1B) in astrocytes was found to inhibit TGFβ signaling. Additionally, YAP was shown to regulate PPM1B ubiquitination and nuclear translocation through immunoprecipitation-Western blot analysis, along with the segregation of cytoplasm and nucleus.

Conclusion

Icariin promotes functional recovery in rats after spinal cord injury by inhibiting YAP and regulating PPM1B ubiquitination to inhibiting the activation of reactive astrocytes.

UAMC-3203 inhibits ferroptosis and promotes functional recovery in rats with spinal cord injury

Spinal cord injury (SCI) results in irreversible neurological impairment. After SCI, Ferritinophagy-induced free iron released from ferritin can lead to extensive lipid peroxidation and aggravate neurological damage. NRF2/HO-1 pathway is to endow cells with a protective effect against oxidative stress, and it plays an important role in the transcriptional activation of a series of antioxidant and detoxification genes. UAMC-3203 is a ferrostatin-1(Fer-1) analogue with better solubility and stability, which can more effectively inhibit ferroptosis after SCI. A rat SCI model was constructed, and the recovery of motor function was observed after treatment with UAMC-3203. ELISA was employed to assess the impact of UAMC-3203 on inflammation-related factors, while immunofluorescence was utilized to investigate the influence of UAMC-3203 on neuronal count as well as the activation of astrocytes and microglia/macrophages. Malondialdehyde (MDA) were detected to reflect the level of oxidation products. Western blot analysis was used to measure the level of ferroptosis markers and the expression of NRF2/HO-1. Our findings demonstrate that UAMC-3203 inhibits the production of reactive oxygen species (ROS) and lipid peroxides, preventing ferroptosis and reducing neuronal degeneration. Additionally, UAMC-3203 suppresses astrocyte proliferation and microglia/macrophage activation, as well as the release of ferroptosis-related inflammatory factors. These combined effects contribute to the preservation of spinal cord tissue and the facilitation of motor function recovery. UAMC-3203 maybe inhibit ferroptosis after SCI to promote functional recovery.

Micro electrical fields induced MSC-sEVs attenuate neuronal cell apoptosis by activating autophagy via lncRNA MALAT1/miR-22-3p/SIRT1/AMPK axis in spinal cord injury

Spinal cord injury (SCI) is a traumatic condition of the central nervous system that causes paralysis of the limbs. Micro electric fields (EF) have been implicated in a novel therapeutic approach for nerve injury repair and regeneration, but the effects of human umbilical cord mesenchymal stem cell-derived small extracellular vesicles that are induced by micro electric fields (EF-sEVs) stimulation on SCI remain unknown. The aim of the present study was to investigate whether EF-sEVs have therapeutic effects a rat model of SCI. EF-sEVs and normally conditioned human umbilical cord mesenchymal stem cells-derived small extracellular vesicles (CON-sEVs) were collected and injected intralesionally into SCI model rats to evaluate the therapeutic effects. We detect the expression of candidate long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNA-MALAT1) in EF-sEVs and CON-sEVs. The targets and downstream effectors of lncRNA-MALAT1 were investigated using luciferase reporter assays. Using both in vivo and in vitro experiments, we demonstrated that EF-sEVs increased autophagy and decreased apoptosis after SCI, which promoted the recovery of motor function. We further confirmed that the neuroprotective effects of EF-sEVs in vitro and in vivo correlated with the presence of encapsulated lncRNA-MALAT1 in sEVs. lncRNA-MALAT1 targeted miR-22-3p via sponging, reducing miR-22-3p's suppressive effects on its target, SIRT1, and this translated into AMPK phosphorylation and increased levels of the antiapoptotic protein Bcl-2. Collectively, the present study identified that the lncRNA-MALAT1 in EF-sEVs plays a neuroprotective role via the miRNA-22-3p/SIRT1/AMPK axis and offers a fresh perspective and a potential therapeutic approach using sEVs to improve SCI.

Resveratrol inhibits ferroptosis via activating NRF2/GPX4 pathway in mice with spinal cord injury

Ferroptosis is a newly defined form of cell death involved in neurologic disease. Resveratrol is a non-flavonoid polyphenolic compound with anti-inflammatory and antioxidant properties, but its potential therapeutic mechanism in spinal cord injury (SCI) remains unknown. Therefore, this study evaluates the mechanism by which resveratrol promotes neurological and motor function recovery in mice with SCI. The motor function of mice was evaluated using the Basso Mouse Scale score and footprint test. The effect of resveratrol on the neuronal cell state was observed using NeuN, fluoro-Jade C, and Nissl staining. The expression of iron content in injured segments was observed using Perls blue and Diaminobenzidine staining. The effect of resveratrol on the levels of malondialdehyde, glutathione, Fe2+ , and glutathione peroxidase 4 enzyme activity was also investigated. The mitochondrial ultrastructures of injured segment cells were observed using transmission electron microscope, while the protein levels of ferroptosis-related targets were detected using Western blot. Our findings show that resveratrol improves motor function after SCI and has certain neuroprotective effects; in ferroptosis-related studies, resveratrol inhibited the expression of ferroptosis-related proteins and ions. Resveratrol improved changes in mitochondrial morphology. Mechanistically, the Nrf2 inhibitor ML385 reversed the inhibitory effect of resveratrol on ferroptosis-related genes, indicating that resveratrol inhibits ferroptosis through the Nrf2/GPX4 pathway. Our findings elucidate that resveratrol promotes functional recovery, inhibits ferroptosis post-SCI, and provides an experimental basis for subsequent clinical translational research. Our study shows that resveratrol inhibits the production of lipid peroxide and the accumulation of iron by activating Nrf2/GPX4 signaling pathway, thereby inhibiting neuronal ferroptosis. At the same time, it can promote the recovery of motor function of mice.

Minocycline relieves neuropathic pain in rats with spinal cord injury via activation of autophagy and suppression of PI3K/Akt/mTOR pathway

OBJECTIVE

In this study, we studied whether minocycline hydrochloride improved neuropathic pain induced by spinal cord injury (SCI) in rats through PI3K/Akt pathway.

METHODS

The SCI was induced by compressed at level of T9-T11 of spinal cord in Sprague Dawley male rats. Animals were given different concentrations of minocycline (3 mg/kg, 30 mg/kg, 90 mg/kg) at the first and 24 h after SCI, then subsequently every 7, 12, 16, 20, 25 days via peroral route. The locomotor function was assessed by Basso Mouse Scale (BMS). The changes of spinal cord tissues were observed by HE. The inflammatory cytokines in spinal cord, IL-6, IL-1β and TNF-α, were measured by ELISA. The LC3B levels of spinal cord were observed by immunofluorescence. The autophagy related proteins and PI3K/AKT pathway related proteins were analysed by Western blot. Furthermore, the PI3K/AKT pathway inhibitor LY294002, and activator IGF-1 were used to confirm the mechanism of minocycline.

RESULTS

Contrasted to sham group, the inflammatory response in spinal cord was enhanced after SCI. Compared with the SCI rats, minocycline treatment significantly improved the locomotor activity, pathological injury of spinal cord, suppressed the levels of inflammatory factors. In addition, minocycline treatment upregulated autophagy response in damaged spinal cord through increasing LC3B, Beclin-1 and decreasing P62. The results of mechanism study showed that minocycline treatment clearly suppressed phosphorylation of PI3K, Akt and mTOR proteins expression.

CONCLUSION

Minocycline could improve neuropathic pain induced by SCI through activating autophagy and inhibiting PI3K/AKT/mTOR pathway.

Therapeutic potential of natural compounds from herbs and nutraceuticals in spinal cord injury: Regulation of the mTOR signaling pathway

Spinal cord injury (SCI) is a disease in which the spinal cord is subjected to various external forces that cause it to burst, shift, or, in severe cases, injure the spinal tissue, resulting in nerve injury. SCI includes not only acute primary injury but also delayed and persistent spinal tissue injury (i.e., secondary injury). The pathological changes post-SCI are complex, and effective clinical treatment strategies are lacking. The mammalian target of rapamycin (mTOR) coordinates the growth and metabolism of eukaryotic cells in response to various nutrients and growth factors. The mTOR signaling pathway has multiple roles in the pathogenesis of SCI. There is evidence for the beneficial effects of natural compounds and nutraceuticals that regulate the mTOR signaling pathways in a variety of diseases. Therefore, the effects of natural compounds on the pathogenesis of SCI were evaluated by a comprehensive review using electronic databases, such as PubMed, Web of Science, Scopus, and Medline, combined with our expertise in neuropathology. In particular, we reviewed the pathogenesis of SCI, including the importance of secondary nerve injury after the primary mechanical injury, the roles of the mTOR signaling pathways, and the beneficial effects and mechanisms of natural compounds that regulate the mTOR signaling pathway on pathological changes post-SCI, including effects on inflammation, neuronal apoptosis, autophagy, nerve regeneration, and other pathways. This recent research highlights the value of natural compounds in regulating the mTOR pathway, providing a basis for developing novel therapeutic strategies for SCI.

Crosstalk between exosomes and autophagy in spinal cord injury: fresh positive target for therapeutic application

Spinal cord injury (SCI) is a very serious clinical traumatic illness with a very high disability rate. It not only causes serious functional disorders below the injured segment, but also causes unimaginable economic burden to social development. Exosomes are nano-sized cellular communication carriers that exist stably in almost all organisms and cell types. Because of their capacity to transport proteins, lipids, and nucleic acids, they affect various physiological and pathological functions of recipient cells and parental cells. Autophagy is a process that relies on the lysosomal pathway to degrade cytoplasmic proteins and organelles and involves a variety of pathophysiological processes. Exosomes and autophagy play critical roles in cellular homeostasis following spinal cord injury. Presently, the coordination mechanism of exosomes and autophagy has attracted much attention in the early efficacy of spinal cord injury. In this review, we discussed the interaction of autophagy and exosomes from the perspective of molecular mechanisms, which might provide novel insights for the early therapeutic application of spinal cord injury.

Astragaloside IV ameliorates spinal cord injury through controlling ferroptosis in H2O2-damaged PC12 cells in vitro

BACKGROUND

Spinal cord injury (SCI) is associated with significant paralysis and high fatality. Recent research has revealed that ferroptosis participates in the pathogenesis of SCI. Astragaloside IV (AS-IV), the main active ingredient of the plant Astragalus membranaceus, has been reported to promote motor function recovery in rats with SCI. This study explored the effects of AS-IV in H2O2-treated PC12 pheochromocytoma cells.

METHODS

The optimal concentration and duration of AS-IV treatment in PC12 cells was assessed using the cell counting kit 8 (CCK-8) assay. Subsequently, the SCI cell model was established in PC12 cells using H2O2. The effects of AS-IV, FIN56, and transcription factor EB (TFEB) small interfering (si)RNA on cell viability and apoptosis in the SCI model were determined using the CCK-8 assay and flow cytometry, respectively. Caspase‑3 and lactate dehydrogenase (LDH) levels were measured by colorimetric assay and enzyme-linked immunosorbent assay (ELISA), respectively. Cellular reactive oxygen species (ROS) were detected by flow cytometry combined with dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. The cellular ultrastructure was analyzed by transmission electron microscopy (TEM). The ferroptosis pathway-related proteins were confirmed using Western blot analysis. TFEB expression was confirmed by Western blot and immunofluorescence.

RESULTS

The optimal concentration and duration of AS-IV treatment in PC12 cells was determined to be 1.0 µM and 48 h, respectively. AS-IV markedly accelerated proliferation, suppressed apoptosis, and reduced ROS and LDH accumulation. Furthermore, AS-IV enhanced TFEB expression in H2O2-damaged PC12 cells. The effects of AS-IV on SCI were inhibited by si-TFEB, and this inhibition was further reinforced by the addition of FIN56.

CONCLUSIONS

The results of this investigation using the SCI cell model suggested that AS-IV alleviated SCI by promoting TFEB expression and subsequently mediating ferroptosis. This may represent a potential clinical treatment for SCI.

The therapeutic potential of triptolide and celastrol in neurological diseases

Neurological diseases are complex diseases affecting the brain and spinal cord, with numerous etiologies and pathogenesis not yet fully elucidated. Tripterygium wilfordii Hook. F. (TWHF) is a traditional Chinese medicine with a long history of medicinal use in China and is widely used to treat autoimmune and inflammatory diseases such as systemic lupus erythematosus and rheumatoid arthritis. With the rapid development of modern technology, the two main bioactive components of TWHF, triptolide and celastrol, have been found to have anti-inflammatory, immunosuppressive and anti-tumor effects and can be used in the treatment of a variety of diseases, including neurological diseases. In this paper, we summarize the preclinical studies of triptolide and celastrol in neurological diseases such as neurodegenerative diseases, brain and spinal cord injury, and epilepsy. In addition, we review the mechanisms of action of triptolide and celastrol in neurological diseases, their toxicity, related derivatives, and nanotechnology-based carrier system.

Neuroprotective Effects of the Pannexin-1 Channel Inhibitor: Probenecid on Spinal Cord Injury in Rats

Proinflammatory immune cell subsets constitute the majority in the local microenvironment after spinal cord injury (SCI), leading to secondary pathological injury. Previous studies have demonstrated that inflammasomes act as an important part of the inflammatory process after SCI. Probenecid, an inhibitor of the Pannexin-1 channel, can inhibit the activation of inflammasomes. This article focuses on the effects of probenecid on the local immune microenvironment, histopathology, and behavior of SCI. Our data show that probenecid inhibited the expression and activation of nucleotide-binding oligomerization domain receptor pyrindomain-containing 1 (NLRP1), apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1, interleukin-1β (IL-1β), and caspase-3 proteins associated with inflammasomes, thereby suppressing the proportion of M1 cells. And consequently, probenecid reduced the lesion area and demyelination in SCI. Moreover, the drug increased the survival of motor neurons, which resulted in tissue repair and improved locomotor function in the injured SC. Altogether, existing studies indicated that probenecid can alleviate inflammation by blocking Pannexin-1 channels to inhibit the expression of caspase-1 and IL-1β, which in turn restores the balance of immune cell subsets and exerts neuroprotective effects in rats with SCI.

Elucidating the Potential Mechanisms Underlying Distraction Spinal Cord Injury-Associated Neuroinflammation and Apoptosis

The incidence of distraction spinal cord injury (DSCI), which results from spinal cord ischemia due to vascular compromise and spinal cord tract disturbances, remains high. Furthermore, because no ideal animal model that mimics DSCI in clinical settings is available thus far, the related molecular mechanisms underlying DSCI remain unclear. Thus, this study aimed to establish a porcine model of DSCI and investigate the neuroinflammation and apoptosis mechanisms in these pigs. Before surgery, all pigs were randomly divided into three groups: sham group, osteotomy surgery only; the incomplete distraction spinal cord injury (IDSCI) and complete distraction spinal cord injury (CDSCI) group, osteotomy plus DSCI surgery with a motor-evoked potential (MEP) amplitude decreased by approximately 75% and 100%, respectively. After surgery, modified Tarlov scoring and MRC muscle strength scoring were used to evaluate neurologic function in each group. We observed the distracted spinal cord using MRI, and then all pigs were sacrificed. Inflammatory cytokine levels in the spinal cord and cerebrospinal fluid (CSF) were also analyzed. We used immunofluorescence staining to assess the neuronal and microglial structure and function and astrocyte hyperplasia in the central DSCI lesions (T15). Western blotting was used to determine the expression of apoptosis-related proteins. Results showed that the modified Tarlov scoring and muscle strength decreased significantly in the two DSCI groups. T2-MRI showed a relative enhancement at the center of the DSCI lesions. H&E and Lxol fast blue staining revealed that spinal cord distraction destroyed the normal structure of spinal cord tissues and nerve fiber tracts, exacerbating inflammatory cell infiltration, hyperemia, and edema. The IL-1β, IL-6, and TNF-α levels increased in the spinal cord and CSF following DSCI. Immunofluorescence staining results indicated the GFAP, Iba-1 expression increased following DSCI, whereas the NeuN expression reduced. Moreover, DSCI promoted the protein expression of P53, Bcl-2-associated X protein (Bax), and Caspase-3 in the spinal cord tissues, whereas it reduced the Bcl-2 expression. This study successfully established a porcine DSCI model that closely mimics DSCI in clinical settings, and clarified the mechanisms underlying DSCI-associated neuroinflammation and apoptosis; thus, our findings highlight potential DSCI-treatment strategies for further establishing suitable drug therapies.

Long-term ketamine administration induces bladder damage and upregulates autophagy-associated proteins in bladder smooth muscle tissue

Long-term ketamine abuse can cause significant lower urinary tract symptoms in humans, termed ketamine-associated cystitis (KC). Here, we established a model of long-term (6 months) ketamine administration in wild-type (C57BL/6) mice. We elucidated the pathological effects of ketamine in the bladder and investigated changes in autophagy-associated protein expression (i.e., LC3, Beclin-1, and P62) and inflammatory cytokines (i.e., IL-6 and IL-1β) in the bladder smooth muscle tissue. Long-term ketamine administration reduced the number of layers in the bladder mucosal epithelial cells (4-5 layers in the saline group vs. 2-3 layers in the ketamine groups), but increased the number of mast cells and collagen fibers. LC3-II/LC3-I, Beclin-1, IL-6, and IL-1β protein expression in the bladder smooth muscle tissues of ketamine-treated mice was significantly increased. The mRNA and protein levels of P62 in the Ket-60 mg/kg group were also significantly increased, but not the Ket-30 mg/kg group. Our results reveal that long-term ketamine administration can cause cystitis-like pathological changes in mice, and the disordered autophagy in the bladder tissue may be involved in the persistent bladder damage following long-term administration of ketamine at 60 mg/kg.

Inhibition of CDK1 attenuates neuronal apoptosis and autophagy and confers neuroprotection after chronic spinal cord injury in vivo

Chronic spinal cord injury (CSCI) results from progressive compression of the spinal cord over time. A variety of factors cause CSCI, and its exact pathogenesis is unknown. Cyclin-dependent kinase 1 (CDK1) is closely related to the apoptosis pathway, but no CSCI-related studies on CDK1 have been conducted. In this study, the role of CDK1 in CSCI was explored in a rat model. The CSCI model was established by screw compression using the cervical anterior approach for twelve weeks. The neurological function of the rats was evaluated using the neurological severity scores (NSS) and motor evoked potentials (MEPs). Pathological changes in spinal cord tissue were observed by hematoxylin-eosin (HE) staining, and Nissl staining was performed to assess the survival of motor neurons in the anterior horn of the spinal cord. Changes in autophagy and apoptosis in anterior horn of spinal cord tissue were detected using transmission electron microscopy and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, respectively. The expression levels of glial fibrillary acidic protein (GFAP), ionized calcium-binding adaptor (IBA) and choline acetyltransferase (CHAT) in the anterior horn were determined using immunohistochemistry assays to investigate astrocytes, microglia and motor neurons, respectively, in the anterior horn. Western blot assays were used to detect the expression levels of CDK1, Bcl-2, Bax, Caspase 3, LC3 and Beclin1. Changes in the expression of CDK1, LC3 and Beclin1 were also observed using immunohistochemistry. The results indicated that CSCI resulted in neuronal injury and a decrease in the NSS. In the CSCI model group, anterior horn astrocytes and microglia were activated, and motor neurons were decreased. Neuronal apoptosis was promoted, and the number of autophagic vacuoles was elevated. Rats treated with the CDK1 shRNA lentivirus exhibited better NSS, more surviving motor neurons, and fewer apoptotic neurons than the model rats. The occurrence of autophagy and the expression of proapoptotic and autophagy-related proteins were lower in the CDK1 shRNA group than the model group. In conclusion, CDK1 downregulation suppressed the activation of anterior horn astrocytes and microglia, promoted motor neuron repair, and inhibited neurons apoptosis and autophagy to promote the recovery of motor function after spinal cord injury.

Anti-neoplastic pharmacophore benzophenone-1 coumarin (BP-1C) targets JAK2 to induce apoptosis in lung cancer

Reigning of the abnormal gene activation associated with survival signalling in lung cancer leads to the anomalous growth and therapeutic failure. Targeting specific cell survival signalling like JAK2/STAT3 nexus has become a major focus of investigation to establish a target specific treatment. The 2-bromobenzoyl-4-methylphenoxy-acetyl hydra acetyl Coumarin (BP-1C), is new anti-neoplastic agent with apoptosis inducing capacity. The current study was aimed to develop antitumor phramacophore, BP-1C as JAK2 specific inhibitor against lung neoplastic progression. The study validates and identifies the molecular targets of BP-1C induced cell death. Cell based screening against multiple cancer cell lines identified, lung adenocarcinoma as its specific target through promotion of apoptosis. The BP-1C is able to induce, specific hall marks of apoptosis and there by conferring anti-neoplastic activity. Validation of its molecular mechanism, identified, BP-1C specifically targets JAK2^Tyr1007/1008 phosphorylation, and inhibits its downstream STAT3^Tyr705 signalling pathway to induce cell death. As a consequence, modulation in Akt/Src survival signal and altered expression of interwoven apoptotic genes were evident. The results were reproducible in an in-vivo LLC tumor model and in-ovo xenograft studies. The computational approaches viz, drug finger printing confers, BP-1C as novel class JAK2 inhibitor and molecular simulations studies assures its efficiency in binding with JAK2. Overall, BP-1C is a novel JAK2 inhibitor with experimental evidence and could be effectively developed into a promising drug for lung cancer treatment.

Polyamine metabolism links gut microbiota and testicular dysfunction

BACKGROUND

Male fertility impaired by exogenous toxins is a serious worldwide issue threatening the health of the new-born and causing infertility. However, the metabolic connection between toxic exposures and testicular dysfunction remains unclear.

RESULTS

In the present study, the metabolic disorder of testicular dysfunction was investigated using triptolide-induced testicular injury in mice. We found that triptolide induced spermine deficiency resulting from disruption of polyamine biosynthesis and uptake in testis, and perturbation of the gut microbiota. Supplementation with exogenous spermine reversed triptolide-induced testicular dysfunction through increasing the expression of genes related to early and late spermatogenic events, as well as increasing the reduced number of offspring. Loss of gut microbiota by antibiotic treatment resulted in depletion of spermine levels in the intestine and potentiation of testicular injury. Testicular dysfunction in triptolide-treated mice was reversed by gut microbial transplantation from untreated mice and supplementation with polyamine-producing Parabacteroides distasonis. The protective effect of spermine during testicular injury was largely dependent on upregulation of heat shock protein 70s (HSP70s) both in vivo and in vitro.

CONCLUSIONS

The present study linked alterations in the gut microbiota to testicular dysfunction through disruption of polyamine metabolism. The diversity and dynamics of the gut microbiota may be considered as a therapeutic option to prevent male infertility. Video Abstract.

Zinc Promotes Microglial Autophagy Through NLRP3 Inflammasome Inactivation via XIST/miR-374a-5p Axis in Spinal Cord Injury

Zinc has reported to play a neuroprotective role in the development of spinal cord injury (SCI). The protective mechanism of zinc remains to be uncovered. The aim of the current study was to investigate the neuroprotective mechanism of zinc in the progression of SCI. The C57BL/6J mouse SCI model was established to confirm the protective role of zinc in vivo, while the cellular model was induced in mouse microglial BV2 cells by using lipopolysaccharide (LPS). The expression levels of XIST, miR-374a-5p and NLRP3 inflammasome as well as the autophagy-related proteins were detected using real-time PCR and immunoblotting. Cell viability was assessed by CCK-8 assay. Apoptosis was evaluated by TUNEL staining, flow cytometry, the determination of apoptosis-related proteins. The target relationship was confirmed by luciferase reporter assays. Zinc improved locomotor function in SCI mice and alleviated LPS-induced BV2 cell injuries by inhibiting apoptosis and initiating autophagy processes. XIST and NLRP3 inflammasome was upregulated while miR-374a-5p was downregulated in spinal cords of SCI mice and LPS-treated BV2 cells. All these effects were inhibited by Zinc treatment. XIST knockdown triggered microglial autophagy-mediated NLRP3 inactivation in LPS-induced BV2 cells by regulating miR-374a-5p. Zinc treatment protected BV2 cells from LPS-induced cell injury by the downregulation of XIST. This process might be through autophagy‑mediated NLRP3 inflammasome inactivation by targeting miR-374a-5p. Zinc downregulates XIST and induces neuroprotective effects against SCI by promoting microglial autophagy-induced NLRP3 inflammasome inactivation through regulating miR-374a-5p. Our finding provides novel opportunities for the understanding of zinc-related therapy of SCI.

Therapeutic impact of thymoquninone to alleviate ischemic brain injury via Nrf2/HO-1 pathway

Introduction: Reactive oxygen species (ROS)-mediated inflammation plays a crucial role in ischemic brain injury. Therefore, the activation of the nuclear erythroid 2 related protein and heme-oxygenase-1 (Nrf2/HO-1) pathway by thymoquinone (TQ) could ameliorate ischemic brain damage.Areas covered: The photo-thrombotic method was employed to assess the impact of TQ in attenuating ischemic brain damage in C57BL/6 J mice and thy1-YFP-16 transgenic mice. In vitro study of TQ efficiency to attenuate the oxygen-glucose deprivation/reoxygenation (OGD/R) induced cell death by fluorescence-activated cell sorting (FACs) analysis was also analyzed. The protein expression levels of Nrf2/HO-1, inflammatory, and apoptotic were evaluated by immunofluorescence and western blot techniques. Besides, mRNA expression level of inducible nitric oxide synthase (iNOS), proto-oncogene (c-MYC), proto-oncogene (c-FOS), 5-hydroxytryptamine receptors (5-HT), and autophagy-related 5 (Atg5) were evaluated by RT-qPCR. The dendritic spine density of YFP slices was determined by confocal microscope.Results: Our in vivo and in vitro results indicated that TQ significantly mitigates brain damage and motor dysfunction after ischemic stroke. These observations coincided with curtailed cell death, inflammation, oxidative stress, apoptosis, and autophagy. Most importantly, Nrf2/HO-1 signaling pathway activation by TQ was vital in the modulation of the above processes. Lastly, we found TQ to have minimal toxicity in liver tissue.Conclusion: Our study gives credence to TQ as a promising intervention therapy for cerebral ischemia that decreases inflammation, oxidative stress, and neuronal cell death via the Nrf2/HO-1 pathway, along with modulation of apoptotic and autophagic processes.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

Triptolide enhances lipolysis of adipocytes by enhancing ATGL transcription via upregulation of p53

Lipolysis is an essential physiological activity of adipocytes. The Patatin Like Phospholipase Domain Containing 2 (PNPLA2) gene encodes the enzyme adipose triglyceride lipase (ATGL) responsible for triglyceride hydrolysis, the first step in lipolysis. In this study, we investigated the potential of triptolide (TP), a natural plant extract, to induce weight loss by examining its effect on ATGL expression. We found that long- and short-term TP administration reduced body weight and fat weight and increased heat production in brown adipose tissue in wild-type C57BL/6 mice. In 3T3-L1 fibroblasts and porcine adipocytes, TP treatment reduced the number of lipid droplets as determined by Oil Red O and BODIPY staining, with concomitant increases in free fatty acid and triglyceride levels in the culture medium. Combined treatment with TP and p53 inhibitor reversed these lipolytic effects. We next amplified the ATGL promoter region and identified conserved p53 binding sites in the sequence by in silico analysis. The results of the dual-luciferase reporter assay using a construct containing the ATGL promoter harboring the p53 binding site showed that p53 induces ATGL promoter activity and consequently, ATGL transcription. These results demonstrate that TP has therapeutic value as an anti-obesity agent and acts by promoting lipolysis via upregulation of p53 and ATGL transcription.

Integrated Proteomics and Metabolomics Reveal the Mechanism of Nephrotoxicity Induced by Triptolide

Triptolide (TP), the main active ingredient of Tripterygium wilfordii Hook F., has great potential in the treatment of autoimmune diseases. However, it has been found that the side effects of TP involve multiple organs and systems, of which the most serious side effects relate to the kidney. The mechanism of nephrotoxicity caused by TP requires further investigation. In the present study, we integrated proteomic and metabolomic methods to identify proteins and small molecule metabolites associated with TP-induced nephrotoxicity. There was a significant difference (p value <0.05) in the expression changes of 357 proteins for quantitative proteomics. In addition, high resolution metabolomic data showed significant changes in the levels of 9 metabolites, including hypoxanthine, PC(22:0/18:4), sphingosine, phenylalanine, etc. Finally, based on the Kyoto Encyclopaedia of Genes and Genomes (KEGG) database for network analysis, it was determined that the 7 differentially expressed proteins were highly correlated with these 9 metabolites. Enrichment analysis revealed that the metabolic pathways involved purine and pyrimidine metabolism, glycerol and phospholipid metabolism, sphingolipid metabolism, and amino acid metabolism. The key target proteins were verified by Western blot technology, and the mechanism of TP-induced nephrotoxicity was further elucidated to provide a basis for safe and rational application.