Celastrol Attenuates Cadmium-Induced Neuronal Apoptosis via Inhibiting Ca2+ -CaMKII-Dependent Akt/mTOR Pathway

Piezo1 Activation Drives Enhanced Collagen Synthesis in Aged Animal Skin Induced by Poly L-Lactic Acid Fillers

Poly L-lactic acid (PLLA) fillers stimulate collagen synthesis by activating various immune cells and fibroblasts. Piezo1, an ion channel, responds to mechanical stimuli, including changes in extracellular matrix stiffness, by mediating Ca2+ influx. Given that elevated intracellular Ca2+ levels trigger signaling pathways associated with fibroblast proliferation, Piezo1 is a pivotal regulator of collagen synthesis and tissue fibrosis. The aim of the present study was to investigate the impact of PLLA on dermal collagen synthesis by activating Piezo1 in both an H2O2-induced cellular senescence model in vitro and aged animal skin in vivo. PLLA elevated intracellular Ca2+ levels in senescent fibroblasts, which was attenuated by the Piezo1 inhibitor GsMTx4. Furthermore, PLLA treatment increased the expression of phosphorylated ERK1/2 to total ERK1/2 (pERK1/2/ERK1/2) and phosphorylated AKT to total AKT (pAKT/AKT), indicating enhanced pathway activation. This was accompanied by upregulation of cell cycle-regulating proteins (CDK4 and cyclin D1), promoting the proliferation of senescent fibroblasts. Additionally, PLLA promoted the expression of phosphorylated mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III in senescent fibroblasts, with GsMTx4 treatment mitigating these effects. In aged skin, PLLA treatment similarly upregulated the expression of pERK1/2/ERK1/2, pAKT/AKT, CDK4, cyclin D1, mTOR/S6K1/4EBP1, TGF-β, and Collagen I/III. In summary, our findings suggest Piezo1's involvement in PLLA-induced collagen synthesis, mediated by heightened activation of cell proliferation signaling pathways such as pERK1/2/ERK1/2, pAKT/AKT, and phosphorylated mTOR/S6K1/4EBP1, underscoring the therapeutic potential of PLLA in tissue regeneration.

Celastrol ameliorates hypoxic-ischemic brain injury in neonatal rats by reducing oxidative stress and inflammation

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is caused by perinatal hypoxia and subsequent reductions in cerebral blood flow and is one of the leading causes of severe disability or death in newborns. Despite its prevalence, we currently lack an effective drug therapy to combat HIE. Celastrol (Cel) is a pentacyclic triterpene extracted from Tripterygium Wilfordi that can protect against oxidative stress, inflammation, and cancer. However, whether Cel can alleviate neonatal hypoxic-ischemic (HI) brain damage remains unclear.

METHODS

Here, we established both in vitro and in vivo models of HI brain damage using CoCl2-treated PC12 cells and neonatal rats, respectively, and explored the neuroprotective effects of Cel in these models.

RESULTS

Analyses revealed that Cel administration reduced brain infarction size, microglia activation, levels of inflammation factors, and levels of oxidative stress markers by upregulating levels of p-AMPKα, Nrf2, HO-1, and by downregulating levels of TXNIP and NLRP3. Conversely, these beneficial effects of Cel on HI brain damage were largely inhibited by AMPKα inhibitor Compound C and its siRNA.

CONCLUSIONS

We present compelling evidence that Cel decreases inflammation and oxidative stress through the AMPKα/Nrf2/TXNIP signaling pathway, thereby alleviating neonatal HI brain injury. Cel therefore represents a promising therapeutic agent for treating HIE.

IMPACT

We firstly report that celastrol can ameliorate neonatal hypoxic-ischemic brain injury both in in vivo and in vitro, which represents a promising therapeutic agent for treating related brain injuries. Celastrol activates the AMPKα/Nrf2/TXNIP signaling pathway to relieve oxidative stress and inflammation and thereby alleviates neonatal hypoxic-ischemic brain injury.

Celastrol Ameliorates Neuronal Mitochondrial Dysfunction Induced by Intracerebral Hemorrhage via Targeting cAMP-Activated Exchange Protein-1

Mitochondrial dysfunction contributes to the development of secondary brain injury (SBI) following intracerebral hemorrhage (ICH) and represents a promising therapeutic target. Celastrol, the primary active component of Tripterygium wilfordii, is a natural product that exhibits mitochondrial and neuronal protection in various cell types. This study aims to investigate the neuroprotective effects of celastrol against ICH-induced SBI and explore its underlying mechanisms. Celastrol improves neurobehavioral and cognitive abilities in mice with autologous blood-induced ICH, reduces neuronal death in vivo and in vitro, and promotes mitochondrial function recovery in neurons. Single-cell nuclear sequencing reveals that the cyclic adenosine monophosphate (cAMP)/cAMP-activated exchange protein-1 (EPAC-1) signaling pathways are impacted by celastrol. Celastrol binds to cNMP (a domain of EPAC-1) to inhibit its interaction with voltage-dependent anion-selective channel protein 1 (VDAC1) and blocks the opening of mitochondrial permeability transition pores. After neuron-specific knockout of EPAC1, the neuroprotective effects of celastrol are diminished. In summary, this study demonstrates that celastrol, through its interaction with EPAC-1, ameliorates mitochondrial dysfunction in neurons, thus potentially improving SBI induced by ICH. These findings suggest that targeting EPAC-1 with celastrol can be a promising therapeutic approach for treating ICH-induced SBI.

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

Cadmium neurotoxicity and therapeutic strategies

Cadmium (Cd) is a multitarget, carcinogenic, nonessential environmental pollutant. Due to its toxic effects at very low concentrations, lengthy biological half-life, and low excretion rate, exposure to Cd carries a concern. Prolonged exposure to Cd causes severe injury to the nervous system of both humans and animals. Nevertheless, the precise mechanisms responsible for the neurotoxic effects of Cd have yet to be fully elucidated. The accurate chemical mechanism potentially entails the destruction of metal-ion homeostasis, inducing oxidative stress, apoptosis, and autophagy. Here we review the evidence of the neurotoxic effects of Cd and corresponding strategies to protect against Cd-induced central nervous system injury.

Mechanical gated ion channel Piezo1: Function, and role in macrophage inflammatory response

Macrophages are present in many mechanically active tissues and are often subjected to varying degrees of mechanical stimulation. Macrophages play a crucial role in resisting pathogen invasion and maintaining tissue homeostasis. Piezo-type mechanosensitive channel component 1 (Piezo1) is the main cation channel involved in the rapid response to mechanical stimuli in mammals. This channel plays a crucial role in controlling blood pressure and motor performance and regulates urinary osmotic pressure and epithelial cell proliferation and division. In recent years, numerous studies have shown that in macrophages, Piezo1 not only plays a role in regulating the aforementioned physiological processes but also participates in multiple pathological processes such as inflammation and cancer. In this review, we summarize the research progress on Piezo1-mediated regulation of macrophage-mediated inflammatory responses through downstream signalling pathways and the aerobic glycolysis pathway.

Insights on Natural Products Against Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that causes the death of motor neurons and consequent muscle paralysis. Despite many efforts to address it, current therapy targeting ALS remains limited, increasing the interest in complementary therapies. Over the years, several herbal preparations and medicinal plants have been studied to prevent and treat this disease, which has received remarkable attention due to their blood-brain barrier penetration properties and low toxicity. Thus, this review presents the therapeutic potential of a variety of medicinal herbs and their relationship with ALS and their physiopathological pathways.

Involvement of the heat shock response (HSR) regulatory pathway in cadmium-elicited cerebral damage

The heat shock response (HSR) is a cellular protective mechanism that is characterized by the induction of heat shock transcription factors (HSFs) and heat shock proteins (HSPs) in response to diverse cellular and environmental stressors, including cadmium (Cd). However, little is known about the relationship between the damaging effects of Cd and the HSR pathway in the chicken cerebrum following Cd exposure. To explore whether Cd exposure elicits cerebral damage and triggers the HSR pathway, chicks were exposed to Cd in the daily diet at different concentrations (35, 70, or 140 mg/kg feed) for 90 days, while a control group was fed the standard diet without Cd. Histopathological examination of cerebral tissue from Cd-exposed chickens showed neuronal damage, as evidenced by swelling and degeneration of neurons, loss of neurons, and capillary damage. Cd exposure significantly increased mRNA expression of HSF1, HSF2, and HSF3, and mRNA and protein expression of three major stress-inducible HSPs (HSP60, HSP70, and HSP90). Moreover, Cd exposure differentially modulated mRNA expression of small HSP (sHSPs), most notably reducing expression of HSP27 (HSPB1). Furthermore, Cd exposure increased TUNEL-positive neuronal apoptotic cells and up-regulated protein expression of caspase-1, caspase-8, caspase-3, and p53, leading to apoptosis. Taken together, these data demonstrate that activation of the HSR and apoptotic pathways by Cd exposure is involved in Cd-elicited cerebral damage in the chicken. Synopsis for the graphical abstract Cadmium (Cd)-induced neuronal damage triggers the heat shock response (HSR) by activating heat shock transcription factors (HSFs) and subsequent induction of major heat shock proteins (notably, HSP60, HSP70, and HSP90). Moreover, Cd exposure activates caspase-1, caspase-8, caspase-3, and p53 protein, thereby resulting in neuronal apoptosis in the chicken brain.

The role of calcium, Akt and ERK signaling in cadmium-induced hair cell death

Exposure to heavy metals has been shown to cause damage to a variety of different tissues and cell types including hair cells, the sensory cells of our inner ears responsible for hearing and balance. Elevated levels of one such metal, cadmium, have been associated with hearing loss and shown to cause hair cell death in multiple experimental models. While the mechanisms of cadmium-induced cell death have been extensively studied in other cell types they remain relatively unknown in hair cells. We have found that calcium signaling, which is known to play a role in cadmium-induced cell death in other cell types through calmodulin and CaMKII activation as well as IP3 receptor and mitochondrial calcium uniporter mediated calcium flow, does not appear to play a significant role in cadmium-induced hair cell death. While calmodulin inhibition can partially protect hair cells this may be due to impacts on mechanotransduction activity. Removal of extracellular calcium, and inhibiting CaMKII, the IP3 receptor and the mitochondrial calcium uniporter all failed to protect against cadmium-induced hair cell death. We also found cadmium treatment increased pAkt levels in hair cells and pERK levels in supporting cells. This activation may be protective as inhibiting these pathways enhances cadmium-induced hair cell death rather than protecting cells. Thus cadmium-induced hair cell death appears distinct from cadmium-induced cell death in other cell types where calcium, Akt and ERK signaling all promote cell death.

Celastrol attenuates 6-hydroxydopamine-induced neurotoxicity by regulating the miR-146a/PI3K/Akt/mTOR signaling pathways in differentiated rat pheochromocytoma cells

BACKGROUND

Parkinson's disease (PD) is a neurological disorder. Recently, celastrol (Cel) has been reported to have neuroprotective properties. We investigated the protective effects of Cel on PD in a cell model with 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in PC12 cells and further addressed the underlying protective mechanisms of Cel.

METHODS

PC12 cells were treated with 6-OHDA, and Cel was added to the medium at various concentrations. The CCK-8 assay, Hoechst/PI staining, and flow cytometry analysis were performed to detect cellular viability and apoptosis. Mitochondrial membrane potential (MMP) was examined by JC-1 staining. ROS level was quantified by ROS staining. The effects of Cel on the expression of miR-146a and PI3K/Akt/mTOR pathway were then clarified using real-time PCR and Western blotting. Moreover, a miR-146a mimic was synthesized and transfected into PC12 cells to further determine the mechanisms of Cel's neuronal protection against 6-OHDA-induced neurotoxicity.

RESULTS

Cel greatly improved cell viability and lessened apoptosis. Flow cytometry showed that Cel especially inhibited early apoptosis. Cel also obviously restored the MMP and decreased ROS level destroyed by 6-OHDA. Moreover, 6-OHDA increased the expression of miR-146a and decreased pAkt/mTOR protein levels, whereas Cel reversed these changes. In particular, miR-146a targeted and inhibited the expression of PI3K, an upstream molecule of Akt/mTOR. Transfection of 6-OHDA-treated neurons with miR-146a mimic notably attenuated Cel's protective effects.

LIMITATIONS

There were no animal experiments in our study.

CONCLUSIONS

Cel exerts neuroprotective activity against 6-OHDA-caused neurotoxicity by regulating miR-146a/PI3K/Akt/mTOR pathway, which provides a potential application of Cel for treating neurodegenerative diseases.

Celastrol and thymoquinone alleviate aluminum chloride-induced neurotoxicity: Behavioral psychomotor performance, neurotransmitter level, oxidative-inflammatory markers, and BDNF expression in rat brain

Exposure to aluminum chloride (AlCl₃) induces progressive multiregional neurodegeneration in animal models by promoting oxidative stress and neuroinflammation. The current study was designed to assess the potential efficacy of the natural antioxidants celastrol and thymoquinone (TQ) for alleviating AlCl₃-induced psychomotor abnormalities and oxidative-inflammatory burden in male albino rats. Four treatment groups were compared: (i) a vehicle control group, (ii) a AlCL₃ group receiving daily intraperitoneal (i.p.) injection of AlCl₃ (10 mg/kg) for 6 weeks, (iii) a AlCl₃ plus TQ (10 mg/kg, i.p.) cotreatment group, and (iv) a AlCl₃ plus celastrol (1 mg/kg, i.p.) cotreatment group. Open-field, rotarod, and forced swimming tests were conducted to assess locomotor activity, motor coordination, anxiety-like behavior, and depressive-like behavior. Acetylcholine (ACh), dopamine, and serotonin levels were measured in brain homogenates. Malondialdehyde (MDA), total antioxidant capacity (TAC), and catalase activity were measured as oxidative stress markers, while tumor necrosis factor-α (TNF-α) and interlukin-6 (IL-6) expression levels were measured as inflammatory markers. Brain derived neurotrophic factor (BDNF) mRNA was measured as an index for the endogenous neuroprotective response. Daily AlCl₃ injection reduced free ambulation, impaired motor coordination, promoted anxiety- and depression-like behaviors, reduced whole-brain ACh, dopamine, and serotonin concentrations, increased MDA accumulation, reduced TAC, elevated TNF-α and IL-6, and suppressed BDNF mRNA expression. All of these effects were significantly reversed by TQ or celastrol cotreatment. Thus, TQ and celastrol may be promising treatments for AlCl₃-induced neurotoxicity as well as neurodegenerative diseases involving oxidative stress and neuroinflammation.

Celastrol inhibits LL37-induced rosacea by inhibiting Ca2+/CaMKII-mTOR-NF-κB activation

Rosacea is a common chronic facial inflammatory disease that affects millions of people worldwide. Due to the unclear etiology of rosacea, effective treatments are limited. Celastrol, a plant-derived triterpene, has been reported to alleviate inflammation in various diseases. However, whether celastrol exerts protective effects in rosacea remains to be elucidated. In this study, weighted gene co-expression network analyses (WGCNA) were performed. Hub modules closely related to rosacea clinical characteristics were identified and found to be involved in inflammation- and angiogenesis-related signaling pathways. Then, the pharmacological targets of celastrol were predicted using the TargetNet and Swiss Target Prediction databases. A GO analysis indicated that the biological process regulated by celastrol highly overlapped with the pathogenic biological processes in rosacea. Next, we showed that celastrol ameliorated erythema, skin thickness and inflammatory cell infiltration in the dermis of LL37-treated mice. Celastrol suppressed the expression of rosacea-related inflammatory cytokines and inhibited the Th17 immune response and cutaneous angiogenesis in LL37-induced rosacea-like mice. We further demonstrated that celastrol attenuated LL37-induced inflammation by inhibiting intracellular-free calcium ([Ca²⁺]_i)-mediated mTOR signaling in keratinocytes. Chelating intracellular Ca²⁺ with BAPTA/AM potentiated celastrol-induced repression of LL37-induced p-S6 elevation. The mTOR agonist MHY1485 dramatically reinforced LL37-induced rosacea-like characteristics, while celastrol attenuated these outcomes. Moreover, celastrol inhibited LL37-activated NF-κB in a mTOR signaling-dependent manner. In conclusion, our findings underscore that celastrol may be a rosacea protective agent by inhibiting the LL37-activated Ca²⁺/CaMKII-mTOR-NF-κB pathway associated with skin inflammation disorders.

Potentilla anserine L. polysaccharide protects against cadmium-induced neurotoxicity

Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway.

In vivo assessment of molybdenum and cadmium co-induce nephrotoxicity via causing calcium homeostasis disorder and autophagy in ducks (Anas platyrhyncha)

Excess molybdenum (Mo) and cadmium (Cd) are widespread environmental and industrial metal pollutants. To evaluate the combined effects of Mo and Cd on calcium homeostasis and autophagy in duck kidneys. 160 healthy 7-day-old ducks (Anas platyrhyncha) were randomized into 4 groups and given to a basic diet, adding various doses of Mo or/and Cd for 16 weeks. On the 4th, 8th, 12th and 16th weeks, kidney tissues were collected. The study exhibited that Mo or/and Cd caused histological abnormality, reduced the activities of Ca2+ ATPase, Mg2+ ATPase, Na+-K+ ATPase and Ca2+-Mg2+ ATPase, K and Mg contents, and increased Na and Ca contents, upregulated CaMKKβ, CaMKIIɑ, CaN, IP3R, GRP78, GRP94, CRT mRNA levels and CaMKIIɑ, CaN, IP3R protein levels. Moreover, exposure to Mo or/and Cd notably promoted the amount of autophagosomes and LC3II immunofluorescence, upregulated AMPKα1, ATG5, Beclin-1, LC3A, LC3B mRNA levels and Beclin-1, LC3II/LC3I protein levels, downregulated mTOR, Dynein, P62 mRNA levels and P62 protein level. The changes of above indicators in combined group were more obvious. Overall, the results suggest that Mo and Cd co-exposure may can synergistically induce nephrotoxicity via causing calcium homeostasis disorder and autophagy in ducks.

METTL14 promotes apoptosis of spinal cord neurons by inducing EEF1A2 m6A methylation in spinal cord injury

Spinal cord injury (SCI) is a devastating traumatic condition. METTL14-mediated m6A modification is associated with SCI. This study was intended to investigate the functional mechanism of RNA methyltransferase METTL14 in spinal cord neuron apoptosis during SCI. The SCI rat model was established, followed by evaluation of pathological conditions, apoptosis, and viability of spinal cord neurons. The neuronal function of primary cultured spinal motoneurons of rats was assessed after hypoxia/reoxygenation treatment. Expressions of EEF1A2, Akt/mTOR pathway-related proteins, inflammatory cytokines, and apoptosis-related proteins were detected. EEF1A2 was weakly expressed and Akt/mTOR pathway was inhibited in SCI rat models. Hypoxia/Reoxygenation decreased the viability of spinal cord neurons, promoted LDH release and neuronal apoptosis. EEF1A2 overexpression promoted the viability of spinal cord neurons, inhibited neuronal apoptosis, and decreased inflammatory cytokine levels. Silencing METTL14 inhibited m6A modification of EEF1A2 and increased EEF1A2 expression while METTL14 overexpression showed reverse results. EEF1A2 overexpression promoted viability and inhibited apoptosis of spinal cord neurons and inflammation by activating the Akt/mTOR pathway. In conclusion, silencing METTL14 repressed apoptosis of spinal cord neurons and attenuated SCI by inhibiting m6A modification of EEF1A2 and activating the Akt/mTOR pathway.

γ-glutamylcysteine suppresses cadmium-induced apoptosis in PC12 cells via regulating oxidative stress

Cadmium (Cd) is a highly toxic environmental pollutant, leading to the occurrence and development of multiple neurological diseases. γ-glutamylcysteine (γ-GC) is a dipeptide formed by the condensation of l-glutamic acid and l-cysteine, which has antioxidant, anti-inflammatory, and chelating properties. The purpose of this study is to investigate the effect of γ-GC on Cd-induced apoptosis in PC12 cells. PC12 cells were pretreated with or without γ-GC (2 mM or 4 mM) for 2 h and exposed to Cd (10 μM) for 12 h, and survival, apoptosis, and oxidative stress of PC12 cells were detected after different treatments. The results showed that γ-GC significantly inhibited cell viability reduction, apoptosis, and depolarization of mitochondrial transmembrane potential in Cd-treated PC12 cells, as indicated by CCK-8 assay, flow cytometry, TUNEL staining, and JC-1 detection. Western blot showed that γ-GC down-regulated the ratio of Bax/Bcl-2 and the protein levels of cytosolic cytopigment c, cleaved-caspase-9, cleaved-caspase-3, and cleaved-PARP. Mechanistically, γ-GC suppressed Cd-induced ROS production, MDA accumulation, and GSH depletion, and increased the activity of antioxidant enzymes. Cd-induced activation of MAPK and PI3K/Akt signaling pathways were inhibited by γ-GC treatment, while sustained phosphorylation of JNK, p38, or Akt reversed anti-apoptotic effects of γ-GC. These results suggested that γ-GC inhibited Cd-induced apoptosis in PC12 cells through decreasing oxidative stress and inhibiting the activation of MAPK and PI3K/Akt signaling pathways. γ-GC could be used as a potential protective agent against Cd neurotoxicity.

The Therapeutic Potential of Celastrol in Central Nervous System Disorders: Highlights from In Vitro and In Vivo Approaches

Celastrol, the most abundant compound derived from the root of Tripterygium wilfordii, largely used in traditional Chinese medicine, has shown preclinical and clinical efficacy for a broad range of disorders, acting via numerous mechanisms, including the induction of the expression of several neuroprotective factors, the inhibition of cellular apoptosis, and the decrease of reactive oxygen species (ROS). Given the crucial implication of these pathways in the pathogenesis of Central Nervous System disorders, both in vitro and in vivo studies have focused their attention on the possible use of this compound in these diseases. However, although most of the available studies have reported significant neuroprotective effects of celastrol in cellular and animal models of these pathological conditions, some of these data could not be replicated. This review aims to discuss current in vitro and in vivo lines of evidence on the therapeutic potential of celastrol in neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases, amyotrophic lateral sclerosis, Huntington’s disease, multiple sclerosis, and cadmium-induced neurodegeneration, as well as in psychiatric disorders, such as psychosis and depression. In vitro and in vivo studies focused on celastrol effects in cerebral ischemia, ischemic stroke, traumatic brain injury, and epilepsy are also described.

Plant-Derived Natural Compounds for the treatment of Amyotrophic Lateral Sclerosis: An Update

Background

Amyotrophic lateral sclerosis (ALS) is a motor neuron disease (MND) that typically causes death within 3-5 years after diagnosis. Regardless of the substantial scientific knowledge accrued more than a century ago, truly effective therapeutic strategies remain distant. Various conventional drugs are being used but are having several adverse effects.

Objective/Aim

The current study aims to thoroughly review plant-derived compounds with well-defined ALS activities and their structure-activity relationships. Moreover, the review also focuses on complex genetics, clinical trials, and the use of natural products that might decrypt the future and novel therapeutics in ALS.

Methods

The collection of data for the compilation of this review work was searched in PubMed Scopus, Google Scholar, and Science Direct.

Results

Results showed that phytochemicals like-Ginkgolides, Protopanaxatriol, Genistein, epigallocatechingallate, resveratrol, cassoside, and others possess Amyotrophic lateral sclerosis (ALS) activity by various mechanisms.

Conclusion

These plant-derived compounds may be considered as supplements for conventional (ALS). Moreover, further preclinical and clinical studies are required to understand the structure-activity relationships, metabolism, absorption, and mechanisms of plant-derived natural agents.

Pharmacological Treatment of Vascular Dementia: A Molecular Mechanism Perspective

Vascular dementia (VaD) is a neurodegenerative disease, with cognitive dysfunction attributable to cerebrovascular factors. At present, it is the second most frequently occurring type of dementia in older adults (after Alzheimer's disease). The underlying etiology of VaD has not been completely elucidated, which limits its management. Currently, there are no approved standard treatments for VaD. The drugs used in VaD are only suitable for symptomatic treatment and cannot prevent or reduce the occurrence and progression of VaD. This review summarizes the current status of pharmacological treatment for VaD, from the perspective of the molecular mechanisms specified in various pathogenic hypotheses, including oxidative stress, the central cholinergic system, neuroinflammation, neuronal apoptosis, and synaptic plasticity. As VaD is a chronic cerebrovascular disease with multifactorial etiology, combined therapy, targeting multiple pathophysiological factors, may be the future trend in VaD.

Inhibiting the Piezo1 channel protects microglia from acute hyperglycaemia damage through the JNK1 and mTOR signalling pathways

AIM

Diabetes is a high-risk factor for neurocognitive dysfunction. Diabetic acute hyperglycaemia accompanied by high osmotic pressure can induce immune cell dysfunction, but its mechanism of action in brain microglia remains unclear. This study aimed to evaluate the role of the mechanically sensitive ion channel Piezo1 in the dysfunction of microglia in acute hyperglycaemia.

MATERIALS AND METHODS

To construct an in vitro acute hyperglycaemia model using the BV2 microglial cell line, Piezo1 in microglia was inhibited by GsMTx4 and siRNA, and the changes in microglial function were further evaluated.

KEY FINDINGS

High concentrations of glucose upregulated the expression of Piezo1, led to weakened cell proliferation and migration, and reduced the immune response to inflammatory stimulating factors (Aβ and LPS). Additionally, LPS upregulated Piezo1 in BV2 microglial cultures in vitro. The activation of Piezo1 channels increased the intracellular Ca²⁺ concentration and reduced the phosphorylation of JNK1 and mTOR. Inhibiting Piezo1 did not affect cell viability at average glucose concentrations but improved acute HCG-induced cell damage and increased the phosphorylation of JNK1 and mTOR, suggesting that the latter modification may be a potential downstream mechanism of Piezo1.

SIGNIFICANCE

Piezo1 is necessary for microglial damage in acute hyperglycaemia and may become a promising target to treat hyperglycaemic brain injury.

Heavy Metals Exposure and Alzheimer's Disease and Related Dementias

Alzheimer's disease and related dementias lack effective treatment or cures and are major public health challenges. Risk for Alzheimer's disease and related dementias is partially attributable to environmental factors. The heavy metals lead, cadmium, and manganese are widespread and persistent in our environments. Once persons are exposed to these metals, they are adept at entering cells and reaching the brain. Lead and cadmium are associated with numerous health outcomes even at low levels of exposure. Although manganese is an essential metal, deficiency or environmental exposure or high levels of the metal can be toxic. In cell and animal model systems, lead, cadmium, and manganese are well documented neurotoxicants that contribute to canonical Alzheimer's disease pathologies. Adult human epidemiologic studies have consistently shown lead, cadmium, and manganese are associated with impaired cognitive function and cognitive decline. No longitudinal human epidemiology study has assessed lead or manganese exposure on Alzheimer's disease specifically though two studies have reported a link between cadmium and Alzheimer's disease mortality. More longitudinal epidemiologic studies with high-quality time course exposure data and incident cases of Alzheimer's disease and related dementias are warranted to confirm and estimate the proportion of risk attributable to these exposures. Given the widespread and global exposure to lead, cadmium, and manganese, even small increases in the risks of Alzheimer's disease and related dementias would have a major population impact on the burden on disease. This article reviews the experimental and epidemiologic literature of the associations between lead, cadmium, and manganese on Alzheimer's disease and related dementias and makes recommendations of critical areas of future investment.

MicroRNA-23b alleviates neuroinflammation and brain injury in intracerebral hemorrhage by targeting inositol polyphosphate multikinase

Neuroinflammation plays a critical role in the pathogenesis of intracerebral hemorrhage (ICH), contributing to detrimental brain injury and neurological function deficits. MicroRNA-23b (miR-23b) exerts anti-inflammatory effects in many diseases and is downregulated in patients with ICH. This study aimed to evaluate the involvement of miR-23b in ICH models in vivo and in vitro, using basal ganglia injection of collagenase type VII in rats and hemin stimulation for cells, respectively. Exogenous overexpression of miR-23b by transfection with lentivirus-miR-23b (LV-miR-23b) or miR-23b mimics was evaluated by RT-qPCR. In this study, we found miR-23b was downregulated in the ICH models and its overexpression effectively alleviated neurological deficits, brain edema, hematoma area, and neuronal apoptosis in ICH rats. Western blotting for neuroinflammation markers and immunofluorescence staining for microglial activation demonstrated that miR-23b could alleviate neuroinflammation in ICH in vivo. We also performed an in vitro mechanism study using BV2 microglial cells and HT22 neuronal cell lines to explore how miR-23b modulates neuroinflammation and neuronal protection after ICH. We found that miR-23b significantly decreased hemin-stimulated inflammation response in BV2 cells and attenuated co-cultured HT22 neuronal cell death. Additionally, we verified that miR-23b suppressed inflammation in BV2 cells by targeting inositol polyphosphate multikinase (IPMK) and that autophagy regulation through the Akt/mTOR pathway was involved in miR-23b-regulated inflammation after ICH. Our study illustrated that miR-23b played a protective role in ICH through inhibiting neuroinflammation by targeting IPMK; this mechanism may be related to the regulation of the Akt/mTOR autophagy pathway, making it a potential target for ICH treatment.

Mechanosensitive ion channel Piezo1 promotes prostate cancer development through the activation of the Akt/mTOR pathway and acceleration of cell cycle

Prostate cancer is one of the most common types of cancer affecting men worldwide; however, its etiology and pathological mechanisms remain poorly understood. Mechanical stimulation plays a key role in prostate cancer development. Piezo type mechanosensitive ion channel component 1 (Piezo1), which functions as a cell sensor and transducer of mechanical stimuli, may have a crucial role in the development of prostate cancer. In the present study, the expression of the Piezo1 channel was demonstrated to be significantly elevated in prostate cancer cell lines and in human prostate malignant tumor tissues. Downregulation of Piezo1 significantly suppressed the viability, proliferation and migration of prostate cancer cells in vitro, and inhibited prostate tumor growth in vivo. The activation of the Akt/mTOR pathway or acceleration of cell cycle progression from G₀/G₁ to S phase may downstream consequences of Piezo 1 signal pathway activation. Downregulation of Piezo1 considerably suppressed Ca²⁺ signal increments, inhibited the phosphorylation of Akt and mTOR and arrested the cell cycle of prostate cancer cells at G₀/G₁ phase in while inhibiting the activation of CDK4 and cyclin D1. Taken together, these findings suggest that Piezo1 channels have a crucial role in prostate cancer development and may, therefore, be a novel therapeutic target in the treatment of prostate cancer.

Celastrol Enhances the Anti-Liver Cancer Activity of Sorafenib

Background

Sorafenib, a multiple-target-point kinase inhibitor, has been used as a standard treatment for advanced liver cancer and has shown therapeutic benefits. However, resistance often occurs, prompting the need for identification of synergizing agents. Celastrol is a major active ingredient of Tripterygium wilfordii, which can increase the antitumor effect of traditional antitumor drugs. This work focused on the sensitization of liver cancers in use of celastrol combined with sorafenib.

Material/Methods

The IC50 values of sorafenib and celastrol on cancer cells were determined through MTT assays. The effects of sorafenib on AKT signaling and VEGF levels in sorafenib-treated cancer cells were analyzed by Western blotting and ELISA, respectively. After combined treatment with celastrol and sorafenib, the survival rate of tumor cells was determined by MTT and clonogenic assays, and the apoptosis rate was also determined by flow cytometry. In addition, the in vivo antitumor activity of celastrol combined with sorafenib was evaluated in Hepa1-6 tumor-bearing mice.

Results

Sorafenib treatment induced the compensatory activation of the AKT pathway and autocrine VEGF in hepatoma cells, which could be reversed by celastrol. Furthermore, celastrol enhanced the growth inhibition and apoptosis induction of cancer cells by sorafenib both in vitro and in vivo and reduced the dosage of sorafenib needed.

Conclusions

Celastrol enhances the antitumor activity of sorafenib in HCC tumor cells by suppressing the AKT pathway and VEGF autocrine system.

Cadmium-induced apoptosis in neuronal cells is mediated by Fas/FasL-mediated mitochondrial apoptotic signaling pathway

Cadmium (Cd) is a toxic metal capable of damaging brain. Studies have demonstrated that Cd can induce apoptosis in neuronal cells. The CD95/APO-1 (Fas)/Fas Ligand (FasL) signaling pathway is one of the primary apoptosis pathways, but the role and regulatory mechanism of this pathway in neuronal cells remain unclear. Here, we demonstrated the underlying mechanism of the Fas/FasL system involving the mitochondrial apoptotic pathway in neuronal cells. Primary rat cerebral cortical neurons and PC12 cells were exposed to Cd, which significantly activated expression of Fas, FasL, Fas-associated death domain (FADD) and cleaved caspase-8. However, expression of cleaved caspase-8 decreased at 20 µM Cd in primary cerebral cortical neurons. Importantly, Cd-induced apoptotic morphological changes and increase in the apoptosis rate were partially blocked by Z-IETD-FMK, which is a specific inhibitor of caspase-8. Cd-mediated increase of apoptosis rate was inhibited by anti-FasL antibody. Furthermore, our data revealed that Z-IETD-FMK also blocked increase of truncated BH3 interacting domain death agonist (tBID)/BID, decrease of the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associate X protein (Bax) ratio and mitochondrial membrane potential (MMP), release of cytochrome c, as well as cleavage of caspase-9/3 and poly (ADP-ribose) polymerase (PARP) induced by Cd. Taken together, our results demonstrate that the Fas/FasL-mediated mitochondrial apoptotic pathway plays an important role in Cd-induced neuronal apoptosis.

Nerol-induced apoptosis associated with the generation of ROS and Ca2+ overload in saprotrophic fungus Aspergillus flavus

The contamination of food with Aspergillus flavus and subsequent aflatoxins is one of the most serious safety problems in the world. In this study of nerol (NEL)'s antifungal mechanism of action, we observed morphological and physiological changes in Aspergillus flavus. We found that NEL resulted in elevated levels of reactive oxygen species (ROS) and calcium ions (Ca²⁺). On ROS assays, compared with the controls, the proportion of fluorescent cells treated with concentrations of 0.25, 0.5, 1, and 2 μL/mL NEL increased to 8.4 ± 1.07%, 10.2 ± 1.72%, 13.4 ± 0.50%, and 26.2 ± 4.21%, respectively. Increased mitochondrial dysfunction and oxidative stress induced by the interactions between Ca²⁺ and ROS subsequently activate the release of cytochrome c and caspase activity. Characteristic changes of apoptosis were also observed via various detection methods, including phosphatidylserine externalization, nuclear condensation, and DNA fragmentation. Meanwhile, we found that the expression of CaMKs increased significantly in NEL-treated cells. In conclusion, our findings indicate that NEL has great potential as an eco-friendly antifungal agent for food preservation.

Celastrol pretreatment attenuates rat myocardial ischemia/ reperfusion injury by inhibiting high mobility group box 1 protein expression via the PI3K/Akt pathway

BACKGROUND/AIMS

Celastrol pretreatment has been shown to protect against myocardial ischemia/reperfusion (I/R) injury, but the underlying mechanism is poorly understood. This study aimed to investigate the cardioprotective effects of celastrol pretreatment on I/R injury and to further explore whether its mechanism of action was associated with the inhibition of high mobility group box 1 protein (HMGB1) expression via the phosphoinositide 3-kinase (PI3K)/Akt pathway.

METHODS

In a fixed-dose study, hematoxylin and eosin staining and myocardial enzyme measurements were used to determine the optimal dose of celastrol that elicited the best cardioprotective effects against I/R injury. Furthermore, rats were pretreated with 4 mg/kg celastrol, and infarct size and the levels of myocardial enzymes, apoptosis, inflammatory and oxidative indices, and HMGB1 and p-Akt expression were measured.

RESULTS

Our results indicated that celastrol dose-dependently attenuated histopathological changes and the elevation in myocardial enzymes induced by I/R. Moreover, the celastrol pretreatment (4 mg/kg) not only significantly decreased infarct size as well as myocardial enzyme levels but also inhibited myocardial apoptosis, inflammatory response and oxidative stress. Additionally, celastrol downregulated HMGB1 expression and upregulated p-Akt expression in the myocardium. LY294002, a specific pI3k inhibitor, partially reversed the decreased HMGB1 expression, increased p-Akt expression induced by celastrol, and abolished the anti-apoptotic, anti-inflammatory and anti-oxidative effects of celastrol.

CONCLUSION

These findings suggest that short-term pretreatment with celastrol protects against myocardial I/R injury by suppressing myocardial apoptosis, inflammatory response and oxidative stress via pI3k/Akt pathway activation and HMGB1 inhibition.

Tripterygium regelii decreases the biosynthesis of triacylglycerol and cholesterol in HepG2 cells

In the course of screening to find a plant material decreasing the activity of triacylglycerol and cholesterol, we identified Tripterygium regelii (TR). The methanol extract of TR leaves (TR-LM) was shown to reduce the intracellular lipid contents consisting of triacylglycerol (TG) and cholesterol in HepG2 cells. TR-LM also downregulated the mRNA and protein expression of the lipogenic genes such as SREBP-1 and its target enzymes. Consequently, TR-LM reduced the TG biosynthesis in HepG2 cells. In addition, TR-LM decreased SREBP2 and its target enzyme HMG-CoA reductase, which is involved in cholesterol synthesis. In this study, we evaluated that TR-LM attenuated cellular lipid contents through the suppression of de novo TG and cholesterol biosynthesis in HepG2 cells. All these taken together, TR-LM could be beneficial in regulating lipid metabolism and useful preventing the hyperlipidemia and its complications, in that liver is a crucial tissue for the secretion of serum lipids.

PARP-1 overexpression contributes to Cadmium-induced death in rat proximal tubular cells via parthanatos and the MAPK signalling pathway

Parthanatos is a newly discovered form of PARP-1-dependent programmed cell death. It has been reported to play an important role in several cancer or tumour cells; however, few studies have been performed in normal cells. Cadmium is a highly toxic pollutant and is reported to induce autophagy and apoptosis in multiple cell types. Although cadmium toxicity induces cell death, the underlying mechanism is not fully understood. Therefore, in this study we aimed to investigate the mechanism of Cadmium -induced cell damage using rat proximal tubular cell line NRK-52E and primary rat proximal tubular (rPT) cells. Our results indicated that parthanatos and the MAPK signalling pathway contribute to Cadmium-induced cell death, and that oxidative stress and mitochondrial damage play key roles in this process. In addition, parthanatos with oxidative stress has a synergistic effect on apoptosis, and JNK1/2 and p38 contribute to parthanatos.