The Calcitonin gene-related peptide (CGRP) receptor has gained attention in Alzheimer’s Disease (AD) research due to its involvement in regulating neuroinflammation. However, its role and mechanism in AD pathology remain unclear. Here, we demonstrate that CALCRL, a core component of the CGRP receptor, is upregulated in the hippocampus of AD dementia patients and 5×FAD mice. Knockout of the CGRP receptor ligand Calca or pharmacological blockade using Rimegepant (Rim), reduces soluble Aβ1-42 oligomer-induced neuronal death and glial inflammation. Rim treatment also rescues neurobehavioral impairments, neurodegeneration, and lipid metabolism dysfunction in 5×FAD mice. Mechanistically, these effects are mediated through HDAC11 inhibition, which enhances LXRβ acetylation and ABCA1 expression, promoting the reprogramming of neuronal lipid metabolism. Importantly, this CALCRL/HDAC11/LXRβ/ABCA1 axis is conserved across both humans and mice. Our findings uncover a novel mechanism underlying AD pathogenesis and highlight the therapeutic potential of targeting CGRP signaling in AD. HIGHLIGHTS Inhibition of CGRP receptor ameliorates disease pathology in models of AD HDAC11 mediates CGRP receptor function in AD HDAC11 is a pivotal regulator in lipid metabolism by LXRβ/ABCA1 signaling The HDAC11/LXRβ/ABCA1 axis is conserved in AD humans and mice ### Competing Interest Statement The authors have declared no competing interest. Science and Technology Commission of Shanghai Municipality, 24141901200 National Natural Science Foundation of China, 32271003, 32571124 the Open Research Fund of Navy Medical University Basic Medical College, ORFBMC-JCKFKT-MS-015 Shanghai Municipal Science and Technology Major Project, 2018SHZDZX01 the Shanghai Center for Brain Science and Brain-Inspired Technology, the Innovative Research Team of High-Level Local University in Shanghai, STI2030-Major Project, 2021ZD0201100, 2021ZD0201104

Intrahepatic cholangiocarcinoma (ICCA), the second most prevalent primary liver malignancy, remains poorly understood at the molecular level. Research into the function of N6-methyladenosine (m6A) modification in the formation of ICCA and its potential as a therapeutic approach is being spurred by mounting evidence that it plays a crucial role in tumor biology. Immunohistochemical examination of patient samples in this investigation revealed a significant decrease in m6A methyltransferase METTL3 expression, accompanied by lower levels, which were associated with a lower overall survival rate. Functional assays demonstrated that the enforced expression of METTL3 inhibited ICCA cell proliferation and migration, while concurrently increasing the levels of the long non-coding RNA H19. Mechanistic experiments using RNA-binding protein immunoprecipitation and methylated RNA immunoprecipitation confirmed that METTL3 directly interacted with H19 and enhanced its m6A modification. Importantly, silencing of H19 reversed the growth- and migration-suppressive effects of METTL3, whereas H19 overexpression counteracted the phenotype induced by METTL3 downregulation. Further analysis revealed that the METTL3-H19 regulatory axis suppressed the expression of peroxisome proliferator-activated receptor gamma (PPARγ). Moreover, an oncolytic adenovirus engineered to overexpress H19, in combination with the PPARγ inhibitor BAY-4931, elicited potent antitumor effects both in vitro and in vivo. Collectively, these findings identify METTL3-mediated m6A modification of H19 as a critical suppressor of ICCA progression through modulation of PPARγ signaling. One interesting treatment option for ICCA may be the use of H19-armed oncolytic adenoviruses, especially when combined with PPARγ suppression.

Parkinson's disease (PD) is a prevalent neurodegenerative disorder accompanied by neuroinflammation. Many studies have demonstrated that interleukin-6 (IL-6) exhibits both anti-inflammatory and pro-inflammatory effects in the central nervous system, yet its role in PD remains controversial. In this study, Il6 -/- (knockout), Il6 +/-, and wild-type mice were utilized to investigate the impact of IL-6 on the pathology of MPTP- or α-SynucleinA53T-induced PD mice. Our findings revealed that Il6 deficiency exacerbated motor dysfunction in both female and male mice. MPTP intoxication resulted in earlier and more extensive injuries to the dopaminergic system and heightened glial reaction in the nigrostriatal pathway of female Il6 -/- mice compared with male Il6 -/- mice, which only displayed more severe dopaminergic neuronal loss at 7 days after MPTP administration. Toxic α-Synuclein overexpression in the substantia nigra region caused earlier motor dysfunction and aggravated dopaminergic neurodegeneration in female Il6 -/- mice. In Il6 +/- mice, MPTP-induced depletion of dopaminergic nerve fibers was unaffected, although astrocyte activation was attenuated. Moreover, intraperitoneal administration of recombinant IL-6 (rIL-6) partially ameliorated MPTP-induced motor dysfunction and striatal dopaminergic terminal depletion in both wild-type and knockout mice. Our findings underscore the crucial role of IL-6 in the inflammatory pathology of PD, highlighting sex-dependent differences, and suggest that rIL-6 holds potential promise for PD therapy.

Parkinsonu2019s disease (PD) is a prevalent neurodegenerative disorder accompanied by neuroinflammation. Many studies have demonstrated that interleukin-6 (IL-6) exhibits both anti-inflammatory and pro-inflammatory effects in the central nervous system, yet its role in PD remains controversial. In this study, Il6u2212 /u2212 (knockout), Il6+/u2212 , and wild-type mice were utilized to investigate the impact of IL-6 on the pathology of MPTP- or u03B1-SynucleinA53T-induced PD mice. Our findings revealed that Il6 deficiency exacerbated motor dysfunction in both female and male mice. MPTP intoxication resulted in earlier and more extensive injuries to the dopaminergic system and heightened glial reaction in the nigrostriatal pathway of female Il6u2212 /u2212 mice compared with male Il6u2212 /u2212 mice, which only displayed more severe dopaminergic neuronal loss at 7 days after MPTP administration. Toxic u03B1-Synuclein overexpression in the substantia nigra region caused earlier motor dysfunction and aggravated dopaminergic neurodegeneration in female Il6u2212 /u2212 mice. In Il6+/u2212 mice, MPTP-induced depletion of dopaminergic nerve fibers was unaffected, although astrocyte activation was attenuated. Moreover, intraperitoneal administration of recombinant IL-6 (rIL-6) partially ameliorated MPTP-induced motor dysfunction and striatal dopaminergic terminal depletion in both wild-type and knockout mice. Our findings underscore the crucial role of IL-6 in the inflammatory pathology of PD, highlighting sex-dependent differences, and suggest that rIL-6 holds potential promise for PD therapy.

IntroductionMixed Lineage Kinase Domain-Like Protein (MLKL), as the executor of necroptosis and a critical factor in the inflammation, has been shown to be associated with the progression of hemorrhagic stroke. Studies identified MLKL is a promoting factor in this process, suggesting its potential as a therapeutic target to mitigate posthemorrhagic stroke damage. However, the mechanisms by which MLKL functions in the process of intracerebral hemorrhage (ICH)-induced damage remain unclear.MethodsHere, we explored the correlation between MLKL and pathological damage in ICH patients through histopathological staining and RT-qPCR. Furthermore, we established an intracerebral hemorrhage model by collagenase IV injection in WT and Mlkl-/- mice. Subsequently, we investigated the impact of MLKL knockout on ICH pathological damage through behavioral tests, Western blotting, and RT-qPCR. Finally, we performed a proteomic analysis via LC-MS/MS to explore the potential interacting proteins of MLKL in the progression of ICH.ResultsWe found that MLKL is highly expressed in the brain tissue of ICH patients and is positively correlated with the extent of injury. However, we found that Mlkl knockout alone was insufficient to fully reverse neuroinflammation and pathological damage. Although Mlkl knockout has a limited effect on alleviating ICH damage, proteomics results indicate that MLKL can mitigate changes in proteins associated with inflammation, metabolism, and coagulation pathways, suggesting that MLKL may exert its effects through these pathways.DiscussionIn summary, our results suggest that although MLKL is associated with the progression of ICH, single knockout of Mlkl is insufficient to fully reverse the pathological damage of ICH. Proteomic analysis indicates that co-targeting MLKL and its associated protein network may yield better therapeutic outcomes for hemorrhagic stroke.

ABSTRACT:The causes of Parkinson's disease are complex, and it is difficult for a single animal model to fully mimic its pathological characteristics. In this study, a comprehensive analysis of behaviors, Parkinson's disease-like pathologies, and gene and protein expression profiles was carried out in three mouse models of disease: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced, α-synuclein (α-syn) A53T transgenic, and MitoPark, revealing both shared and model-specific pathogenic pathways to guide model selection and identify potential therapeutic targets. All three Parkinson's disease models exhibited motor impairments, with particularly pronounced age-related decline observed in MitoPark mice. Pathologically, nigrostriatal pathway damage was observed in all models, yet with distinct patterns of glial cell activation. Sixteen-month-old α-syn A53T mice displayed a few pS129-α-syn-positive signals in the substantia nigra, while no α-syn aggregates were observed in any of the models. RNA sequencing and proteomics analysis revealed significant changes in gene and protein expression, with both unique and common features among the three models. Five common differentially expressed genes (Ifi27l2a, Ifitm3, Oasl2, Rtp4, and Ankk1) and two common differentially expressed proteins (Timm8a1 and Sephs1) were identified. Functional enrichment analysis indicated that immune responses, cytokines, and neurotransmitter transport were crucial in Parkinson's disease pathogenesis. Notably, multiple iron-related cell damage (ferroptosis)-related differentially expressed genes were identified across all three models, while interleukin 17 pathway activation was altered in MitoPark mice. In summary, we analyzed the commonalities and specificities of pathological simulation capabilities and common disease mechanisms in different mouse models of Parkinson's disease from multiple perspectives. Our findings offer valuable insights into the multifaceted characteristics of Parkinson's disease and will assist in model selection for mechanistic exploration in the future.

Interleukin-33 (IL33) plays a critical role in modulating immune and inflammatory responses across various diseases, yet its influence on Parkinson's disease (PD) remains elusive. In this study, we provide substantial evidence that global depletion of Il33 exacerbates PD pathology and motor deficits in vivo. Moreover, Il33 deficiency diminishes the communication between astrocytes and microglia, leading to a more profound injury to primary neurons in vitro. Notably, the application of recombinant IL33 (rIL33) following MPTP treatment or α-synucleinA53T overexpression partially inhibits the reduction in TH expression, glial activation, and the motor dysfunctions in vivo. Collectively, our findings demonstrate the opposed effects of Il33 deletion and rIL33 administration on neuroinflammation in PD, emphasizing the therapeutic potential of IL33 in regulating neuroinflammation and neuronal viability in the central nervous system (CNS).

Non-small cell lung cancer (NSCLC) represents between 80 and 90% of primary lung cancer cases. Despite progress targeting oncogenic drivers, there are no therapies targeting tumor-suppressor loss. This study confirmed a significant downregulation of SMAD4 expression in both NSCLC tissues and cell lines. Loss of SMAD4 was associated with advanced clinical stage, pathological T stage, and poor prognosis for chemotherapy in NSCLC patients. SMAD4 knockdown promoted proliferation, cell cycle progression, migration, and invasion in NSCLC cells, whereas SMAD4 overexpression suppressed these malignant phenotypes. The molecular mechanism underlying SMAD4 loss-driven NSCLC progression links to the abnormal activation of Wnt/β-catenin pathway. Subsequently, an oncolytic adenovirus encoding SMAD4 (OAd CS) was constructed and its efficiency in inhibiting NSCLC growth was assessed. OAd CS selectively replicated in and killed NSCLC cells without affecting the survival of normal lung cells. Mechanistically, CS inhibited NSCLC cell growth through suppressing the Wnt/β-catenin pathway and activating the caspase pathway. Furthermore, combining OAd CS with gemcitabine exhibited superior tumor suppression compared to monotherapy, with no significant toxicity observed in a NSCLC xenograft model. Overall, these findings provide a novel therapeutic target and an additional combination therapy strategy for NSCLC.

Parkinson’s disease (PD) is a prevalent neurodegenerative disorder with indistinct etiology and ill-defined pathophysiology. Intestinal inflammation involved in the pathogenesis of PD, but the underlying mechanism is not fully understood. Citrobacter rodentium (C.R) is a gram-negative bacterium that can be used to induce human inflammatory bowel disease in mice. Here, we investigated whether the proinflammatory effects caused by C.R infection initiate PD-like injury and/or exacerbate PD pathology and extensively studied the underlying mechanism. Mice were gavaged once with C.R and monitored for several pathological features at 9 days post infection. The results showed that C.R delivery in mice induced IBD-like symptoms, including significant weight loss, increased fecal water content, an impaired intestinal barrier, intestinal hyperpermeability and inflammation, and intestinal microbiota disturbances. Notably, C.R infection modified dopamine (DA) metabolism in the brains of both male and female mice. Subsequently, a single high dose of MPTP or normal saline was administered at 6 days post infection. At 3 days after MPTP administration, the feces were collected for 16 S rRNA analysis, and PD-like phenotypes and mechanisms were systemically analyzed. Compared with C.R or MPTP injection alone, the injection of C.R and MPTP combined worsened behavioral performance. Moreover, such combination triggered more severe dopaminergic degeneration and glial cell overactivation in the nigrostriatal pathway of mice. Mechanistically, the combination of C.R and MPTP increased the expression of TLR4 and NF-κB p65 in the colon and striatum and upregulated proinflammatory cytokine expression. Therefore, C.R infection-induced intestinal inflammation can impair dopamine metabolism and exacerbate PD pathological processes.

Purpose: Vaccinia virus is widely used as an oncolytic agent for human cancer therapy, and several versions of vaccinia virus have demonstrated robust antitumor effects in breast cancer. Most vaccinia viruses are modified by thymidine kinase (TK) deletion. The function of the cyclin-dependent kinase inhibitor p21 in breast cancer remains controversial. We explored the impact of p21 gene knockdown (KD) on breast cancer cells and whether p21 KD interferes with the antitumor effect ofTK-negative vaccinia virus. Methods: p21 KD MDA-MB-231 and p21 KD MCF-7 cells were prepared, and cell proliferation and migration rates were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide (MTT) and scratch healing assays. The tumor growth of xenografts originating from p21KD MDA-MB-231 cells and control cells was compared in a mouse model. The colony formation and sphere-forming abilities of p21 KD breast cancer cells were also determined using low-melting agarose and serum-free culture. The tumor- killing effect of the vaccinia virus was determined in breast cancer cells and mouse models using an MTT assay and tumor cell xenografts. Results: p21 KD increased the growth and migration of MDA-MB-231 and MCF-7 cells and promoted the cell growth of MDA-MB-231 cells in mice, while decreasing the colony formation and sphere formation abilities. Expression ofTKwas reduced in p21 KD MDAMB-231 cells. Oncolytic effects of both wild-type and TK-deleted vaccinia viruses were attenuated in p21KD MDA-MB-231 cells. The tumor-killing effect of TK-deleted vaccinia virus was also weakened in xenografted mice bearing p21 KD MDA-MB-231 cells. Conclusion: Targeted inhibition of p21 accelerates the proliferation and migration of breast cancer cells and impairs the tumor-killing effect ofvaccinia virus, suggesting that p21 levels in cancer cells interfere with vaccinia virus oncolytic therapy.

GSDMD-mediated pyroptosis occurs in the nigrostriatal pathway in Parkinson’s disease animals, yet the role of GSDMD in neuroinflammation and death of dopaminergic neurons in Parkinson’s disease remains elusive. Here, our in vivo and in vitro studies demonstrated that GSDMD, as a pyroptosis executor, contributed to glial reaction and death of dopaminergic neurons across different Parkinson’s disease models. The ablation of the Gsdmd attenuated Parkinson’s disease damage by reducing dopaminergic neuronal death, microglial activation, and detrimental transformation. Disulfiram, an inhibitor blocking GSDMD pore formation, efficiently curtailed pyroptosis, thereby lessening the pathology of Parkinson’s disease. Additionally, a modification in GSDMD was identified in the blood of Parkinson’s disease patients in contrast to healthy subjects. Therefore, the detected alteration in GSDMD within the blood of Parkinson’s disease patients and the protective impact of disulfiram could be promising for the diagnostic and therapeutic approaches against Parkinson’s disease.

Microglial activation contributes to neurological disorders like Parkinson’s disease (PD), and modulating this activation is a potential therapeutic approach. The neuron-restrictive silencer factor (NRSF) functions as a negative regulator of gene transcription through epigenetic modifications. While previous research has primarily examined the role of NRSF in neuronal differentiation and injury, emerging evidence indicates that NRSF also plays a significant role in maintaining the phenotype of glial cells. In this study, we explored the role and underlying mechanisms of NRSF in lipopolysaccharide (LPS)-induced pro-inflammatory or interleukin-4 (IL4)-induced anti-inflammatory phenotype of microglial activation. Following LPS stimulation, the nuclear localization of NRSF increased in BV2 microglial cells, primary mouse microglia, and microglia within the substantia nigra of PD mice. Knockdown of NRSF enhanced the expression of inflammation-related factors induced by LPS via the mitogen-activated protein kinase-extracellular signal-regulated kinase (MAPK-ERK) and nuclear factor-κB (NF-κB) p65 signalling pathways in BV2 cells. Moreover, the culture medium from LPS-treated NRSF knockdown BV2 cells exerted greater toxic effects on human neuroblastoma SH-SY5Y cells compared to the control. However, NRSF knockdown exerted inconsistent effects on the expression of anti-inflammatory-related genes in IL4-treated BV2 cells. Our findings suggest that NRSF knockdown promotes microglial pro-inflammatory activation.

Neuroinflammation is one of the core pathological features of Parkinson’s disease (PD). Innate immune cells play a crucial role in the progression of PD. Microglia, the major innate immune cells in the brain, exhibit innate immune memory effects and are recognized as key regulators of neuroinflammatory responses. Persistent modifications of microglia provoked by the first stimuli are pivotal for innate immune memory, resulting in an enhanced or suppressed immune response to second stimuli, which is known as innate immune training and innate immune tolerance, respectively. In this study, LPS was used to establish in vitro and in vivo models of innate immune memory. Microglia-specific Hif-1α knockout mice were further employed to elucidate the regulatory role of HIF-1α in innate immune memory and MPTP-induced PD pathology. Our results showed that different paradigms of LPS could induce innate immune training or tolerance in the nigrostriatal pathway of mice. We found that innate immune tolerance lasting for one month protected the dopaminergic system in PD mice, whereas the effect of innate immune training was limited. Deficiency of HIF-1α in microglia impeded the formation of innate immune memory and exerted protective effects in MPTP-intoxicated mice by suppressing neuroinflammation. Therefore, HIF-1α is essential for microglial innate immune memory and can promote neuroinflammation associated with PD.

IntroductionColorectal cancer (CRC) is a highly prevalent digestive system malignancy. Aspirin is currently one of the most promising chemopreventive agents for CRC, and the combination of aspirin and natural compounds helps to enhance the anticancer activity of aspirin. Natural flavonoids like vitexin have an anticancer activity focusing on colorectal carcinoma.MethodsThis study investigated the potential mechanism of action of the novel combination of vitexin and aspirin against colorectal cancer through network pharmacology, molecular docking, molecular dynamics simulation, and in vitro experiments.ResultsThe results of network pharmacology suggested that vitexin and aspirin regulate multiple signaling pathways through various target proteins such as NFKB1, PTGS2 (COX-2), MAPK1, MAPK3, and TP53. Cellular experiments revealed that the combined effect of vitexin and aspirin significantly inhibited HT-29 cell growth. Vitexin dose-dependently inhibited COX-2 expression in cells and enhanced the down-regulation of COX-2 and NF-κB expression in colorectal cancer cells by aspirin.DiscussionThis study provides a pharmacodynamic material and theoretical basis for applying agents against colorectal cancer to delay the development of drug resistance and improve the prognosis of cancer patients.

Parkinson’s disease (PD) is mainly characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and neuroinflammation mediated by overactivated microglia and astrocytes. NLRC5 (nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 5) has been reported to participate in various immune disorders, but its role in neurodegenerative diseases remains unclear. In the current study, we found that the expression of NLRC5 was increased in the nigrostriatal axis of mice with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced PD, as well as in primary astrocytes, microglia and neurons exposed to different neurotoxic stimuli. In an acute MPTP-induced PD model, NLRC5 deficiency significantly reduced dopaminergic system degeneration and ameliorated motor deficits and striatal inflammation. Furthermore, we found that NLRC5 deficiency decreased the expression of the proinflammatory genes IL-1β, IL-6, TNF-α and COX2 in primary microglia and primary astrocytes treated with neuroinflammatory stimuli and reduced the inflammatory response in mixed glial cells in response to LPS treatment. Moreover, NLRC5 deficiency suppressed activation of the NF-κB and MAPK signaling pathways and enhanced the activation of AKT–GSK-3β and AMPK signaling in mixed glial cells. Furthermore, NLRC5 deficiency increased the survival of primary neurons treated with MPP+ or conditioned medium from LPS-stimulated mixed glial cells and promoted activation of the NF-κB and AKT signaling pathways. Moreover, the mRNA expression of NLRC5 was decreased in the blood of PD patients compared to healthy subjects. Therefore, we suggest that NLRC5 promotes neuroinflammation and dopaminergic degeneration in PD and may serve as a marker of glial activation.

NRSF/REST (neuron-restrictive silencer element, also known as repressor element 1-silencing transcription factor), plays a key role in neuronal homeostasis as a transcriptional repressor of neuronal genes. NRSF/REST relates to cognitive preservation and longevity of humans, but its specific functions in age-dependent and Alzheimer's disease (AD)-related memory deficits remain unclear. Here, we show that conditional NRSF/REST knockout either in the dorsal telencephalon or specially in neurons induced an age-dependently diminished retrieval performance in spatial or fear conditioning memory tasks and altered hippocampal synaptic transmission and activity-dependent synaptic plasticity. The NRSF/REST deficient mice were also characterized by an increase of activated glial cells, complement C3 protein and the transcription factor C/EBPβ in the cortex and hippocampus. Reduction of NRSF/REST by conditional depletion upregulated the activation of astrocytes in APP/PS1 mice, and increased the C3-positive glial cells, but did not alter the Aβ loads and memory retrieval performances of 6- and 12-month-old APP/PS1 mice. Simultaneously, overexpression of NRSF/REST improved cognitive abilities of aged wild type, but not in AD mice. These findings demonstrated that NRSF/REST is essential for the preservation of memory performance and activity-dependent synaptic plasticity during aging and takes potential roles in the onset of age-related memory impairments. However, while altering the glial activation, NRSF/REST deficiency does not interfere with the Aβ deposits and the electrophysiological and cognitive AD-like pathologies.

The use of oncolytic viruses as a gene therapy vector is an area of active biomedical research, particularly in the context of cancer treatment. However, the actual therapeutic success of this approach to tumor elimination remains limited. As such, the present study was developed with the goal of simultaneously enhancing the antitumor efficacy of oncolytic viruses and the local immune response by combining the Ad-GD55 oncolytic adenovirus and an antibody specific for the TIM-3 immune checkpoint molecule (α-TIM-3). The results of Virus and cell-mediated cytotoxicity assay, qPCR, and Western immunoblotting showed that Ad-GD55–α-Tim-3 oncolytic adenovirus is capable of inducing α-TIM-3 expression within hepatoma cells upon infection, and Ad-GD55–α-TIM-3 exhibited inhibitory efficacy superior to that of Ad-GD55 when used to treat these tumor cells together with the induction of enhanced intracellular immunity. In vivo experiments revealed that Ad-GD55–α-TIM-3 administration was sufficient to inhibit tumor growth and engage in a more robust local immune response within the simulated tumor immune microenvironment. These results highlighted the promising therapeutic effects of Ad-GD55–α-TIM-3 oncolytic adenovirus against HCC in vitro and in vivo. As such, this Ad-GD55–α-TIM-3 oncolytic adenovirus may represent a viable approach to the treatment of hepatocellular carcinoma.

Histone deacetylase 6 (HDAC6) is involved in the regulation of protein aggregation and neuroinflammation, but its role in Parkinson’s disease (PD) remains controversial. In this study, Hdac6−/− mice were generated by CRISPR-Cas9 technology for exploring the effect of HDAC6 on the pathological progression of PD. We found that male Hdac6−/− mice exhibit hyperactivity and certain anxiety. In the acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, though motor injury was slightly alleviated by HDAC6 deficiency, dopamine (DA) depletion in the striatum, the decrease in the number of DA neurons in the substantia nigra (SN) and the reduction in DA neuronal terminals were not affected. In addition, activation of glial cells and the expression of α-synuclein, as well as the levels of apoptosis-related proteins in the nigrostriatal pathway, were not changed in MPTP-injected wild-type and Hdac6−/− mice. Therefore, HDAC6 deficiency leads to moderate alterations of behaviors and Parkinson’s disease pathology in mice.

Aims: Parkinson's disease (PD) is a progressive neurodegenerative disorder. The etiology of PD is still elusive but neuroinflammation is proved to be an important contributor. Toll-like receptor 2 (TLR2) involves in the release of several inflammatory cytokines. Whether TLR2 serves as a mediator contributing to the damage of DA system in PD remain unclear.Main methods: Tlr2 knockout (Tlr2(-/-)) and wild-type (WT) mice were treated with a subacute regimen of 1methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). At 3, 7 and 14 days after MPTP injection, the behavioral performance, including the Pole test, the Rotarod test, the Rearing test and the Wire hang test was evaluated. Moreover, the PD-like phenotypes, including dopaminergic degeneration, the activation of glial cells and the alpha-Syn expression were systematically analyzed in the nigrostriatal pathway. Finally, the composition of gut microbiota in the MPTP-treated groups were assessed.Key findings: TLR2 deficiency had no obvious impact on the dopaminergic injury at 3 and 7 days following MPTP administration. On the contrary, at 14 days post injection, TLR2 deficiency not only significantly attenuated motor deficits in the Pole test and the Rotarod test, and the nigrostriatal dopaminergic degeneration, but also mitigated alpha-Syn abnormality, astrocyte activation and neuroinflammation through the suppressed TLR2/ MyD88/TRAF6/NF-kappa B signaling pathways. Additionally, the alteration of gut microbiota was also detected in the mutant mice.Significance: These findings highlight the neuroprotective effect of TLR2-pathways at the late phase in the MPTPinduced PD mouse model.

The transforming growth factor (TGF)-β signaling pathway controls many cellular processes, including proliferation, differentiation, and apoptosis. Abnormalities in the TGF-β signaling pathway and its components are closely related to the occurrence of many human diseases, including cancer. Mothers against decapentaplegic homolog 4 (Smad4), also known as deleted in pancreatic cancer locus 4, is a typical tumor suppressor candidate gene locating at q21.1 of human chromosome 18 and the common mediator of the TGF-β/Smad and bone morphogenetic protein/Smad signaling pathways. It is believed that Smad4 inactivation correlates with the development of tumors and stem cell fate decisions. Smad4 also interacts with cytokines, miRNAs, and other signaling pathways, jointly regulating cell behavior. However, the regulatory function of Smad4 in tumorigenesis, stem cells, and drug resistance is currently controversial. In addition, Smad4 represents an attractive therapeutic target for cancer. Elucidating the specific role of Smad4 is important for understanding the mechanism of tumorigenesis and cancer treatment. Here, we review the identification and characterization of Smad4, the canonical TGF-β/Smad pathway, as well as the multiple roles of Smad4 in tumorigenesis, stem cells, and drug resistance. Furthermore, we provide novel insights into the prospects of Smad4-targeted cancer therapy and the challenges that it will face in the future.