Search Results (2,822)

Validated biomarkers for clinical decision-making in spondyloarthritis (SpA) remain limited, and exploratory experimental studies may help prioritize candidate immune and bone-related readouts for future validation. In this pilot study, cytokine and bone-related biomarker profiles were analyzed in a proteoglycan-induced SpA model using Th1-prone C57BL/6J wild-type (WT) mice (non-immunized n = 8; immunized n = 16) and Th2-prone BALB/c WT mice (non-immunized n = 7; immunized n = 9), as well as immunized TLR2-knockout (KO) (n = 7), TLR3-KO (n = 8), and TLR4-KO (n = 3) strains on the C57BL/6J background. Serum cytokines were quantified longitudinally with a 26-plex immunoassay, and ELISA measured bone metabolism markers (DKK1, Wnt3a, Noggin). Cytokine analysis revealed distinct Th1/Th2 polarization: immunized Th1-prone C57BL/6J WT mice exhibited high Th1- and Th17-type cytokines (TNF-α, IFNγ, IL-12p70, IL-17A, and IL-22), whereas immunized Th2-prone BALB/c WT mice showed elevated Th2- and eosinophil-related cytokines (IL-4, IL-9, IL-13, IL-5, and RANTES). In TLR2-KO and TLR3-KO, Th1- and Th17-associated cytokines were markedly reduced, while Th2 cytokines were increased, confirming that TLR2 is essential for maintaining pro-inflammatory signaling. DKK-1 and Noggin levels were significantly higher in TLR2-KO mice, indicating altered terminal serum bone-marker profiles under immunized conditions. These findings indicate that Th1/Th2 immune backgrounds and TLR-associated contexts are associated with distinct cytokine patterns and differences in terminal bone markers in this experimental SpA model. Given the pilot design, small and imbalanced groups, missing non-immunized TLR-KO controls, and exploratory statistics without multiplicity adjustment, the results should be interpreted as hypothesis-generating and require confirmation in appropriately controlled, statistically powered studies incorporating longitudinal and structural endpoints, as the present findings are exploratory and not directly translatable to clinical biomarker use or therapeutic decision-making. Full article

Obesity is associated with profound metabolic, inflammatory, and neurobehavioral dysfunctions. Dietary interventions leading to weight loss are commonly employed, yet it remains unclear whether all obesity-related alterations are fully reversed upon reaching normal body weight. Poor adherence to dietary regimens often results in weight cycling, or yo-yo dieting, characterized by repeated episodes of weight gain and loss, a phenomenon linked to adverse health outcomes. Here, we investigated the consequences of weight cycling in C57BL/6J mice. The Control Group was maintained on a standard chow diet throughout the protocol, whereas the experimental group underwent two alternating cycles of high-fat diet feeding (weight gain) and standard diet reversion (weight loss), until the end of the protocol where both groups reached 80 weeks of age. Despite achieving a final body weight and glucose and lipid metabolic profile comparable to lean controls, weight-cycled mice exhibited impaired sensorimotor function, increased anxiety-like behavior (evaluated through behavioral tests), and persistent inflammation, including a peritoneal macrophage pro-inflammatory profile and adipose tissue infiltration. We define this phenomenon as “obesogenic inflammatory memory”, highlighting that obesity leaves an immunological imprint that sustains inflammation even after normalization of weight and metabolic parameters. These findings demonstrate that weight cycling is associated with chronic macrophage-mediated inflammatory states, linked to long-term behavioral and neurological manifestations, and opening new avenues for future investigation and therapeutic approaches. Full article

Background: Neurodegeneration and dementia are key factors in Alzheimer’s disease (AD). The deposition of amyloid-ß into senile plaques in the brain parenchyma and in cerebral vessels known as cerebral amyloid angiopathy (CAA) are the main clinical parameters of AD. Acute myocardial infarction (AMI) and AD share a comparable pathophysiology. However, the underlying mechanisms and the consequences of AMI in AD patients are unclear to date. Methods: AD transgenic APP23 mice were analyzed in experimental AMI using the closed-chest model. Results: APP23 mice displayed significantly decreased left ventricular function as detected by FS/MPI (fractional shortening/myocardial performance index) after 24 h and 3 weeks after ligation of the LAD compared to WT controls. No differences have been observed in infarct and scar size. The analysis of cardiac remodeling after 3 weeks showed an altered composition of the collagen tissue of the scar with elevated tight but reduced fine collagen in APP23 mice. Altered scar formation was accompanied by elevated degranulation of platelets following activation of the collagen receptor GPVI. Conclusions: These results suggest that AD patients are at higher risk for cardiac damage after AMI. This implies the need for a personalized therapy of AMI in AD patients. Full article

Background: Mycoplasma pneumoniae pneumonia (MPP) is a common community-acquired pneumonia in children. Increasing drug resistance highlights the need for more effective treatments with fewer side effects. The Qingfei Tongluo Jiedu formula (QTJD) has demonstrated clinical efficacy against MPP; however, its underlying mechanisms remain unclear. This study aimed to explore the mechanism of QTJD on MPP using network pharmacology and in vitro experiments. Methods: Network pharmacology was used to identify the active compounds and signaling pathways of QTJD in MPP. QTJD-containing serum was prepared, and primary mouse lung and bone marrow cells were isolated to examine the effects of QTJD on macrophage polarization through butyric acid. Cell viability assays, flow cytometry, and quantitative reverse transcription-polymerase chain reaction were performed. GPR109^−/− cells were used to confirm the receptor mediating butyric acid’s action, and Western blotting was employed to assess the MAPK signaling pathway. Results: QTJD promoted macrophage polarization and alleviated the inflammatory response caused by Mycoplasma pneumoniae. High-performance liquid chromatography-electrospray ionization mass spectrometry combined with network pharmacology identified 20 active compounds. Protein-protein interaction analysis revealed 10 core target, including JUN and Tumor Necrosis Factor (TNF), while enrichment analysis highlighted pathways such as Mitogen-Activated Protein Kinase (MAPK) and Phosphoinositide 3-Kinase-Protein Kinase B. Experimental validation demonstrated that QTJD reduced M1 markers (CD86, CXCL10) by increasing butyrate levels (p < 0.01) and enhanced M2 markers (CD206, Arg-1, MRC-1), promoting M2 polarization. QTJD inhibited ERK1/2, p38, and JNK1/2 (p < 0.01). In GPR109A^−/− mice macrophages, QTJD suppressed p38 and JNK1/2 (p < 0.01) but showed no effect on ERK1/2 (p > 0.05), confirming involvement of the butyrate-GPR109A-MAPK pathway. Conclusions: QTJD effectively alleviates MPP by regulating macrophage polarization through the butyrate-GPR109A-MAPK pathway. Future studies should explore how QTJD modulates pulmonary immunity through gut microbiota and butyrate production and elucidate its immunoregulatory mechanisms along the gut-lung axis using multi-omics approaches. Full article

This study investigates whether fecal microbiota transplantation (FMT) can alleviate gut microbiota dysbiosis induced by a high-fat diet (HFD) through modulation of fatty acid metabolism, competition for nutrients, production of short-chain fatty acids (SCFAs), and restoration of mucus layer integrity. To elucidate the mechanisms by which FMT regulates colonic microbial function and host metabolic responses, 80 male Bal b/c mice were randomly assigned to four experimental groups (n = 20 per group): Normal Diet Group (NDG), High-Fat Diet Group (HDG), Restrictive Diet Group (RDG), and HDG recipients of NDG-derived fecal microbiota (FMT group). The intervention lasted for 12 weeks, during which body weight was monitored biweekly. At the end of the experiment, tissue and fecal samples were collected to assess digestive enzyme activities, intestinal histomorphology, gene expression related to gut barrier function, and gut microbiota composition via 16S rRNA gene sequencing. Results showed that mice in the HDG exhibited significantly higher final body weight and greater weight gain compared to those in the NDG and RDG (p < 0.05). Notably, FMT treatment markedly attenuated HFD-induced weight gain (p < 0.05), reducing it to levels comparable with the NDG (p > 0.05). While HFD significantly elevated the activities of α-amylase and trypsin (p < 0.05), FMT supplementation effectively suppressed these enzymatic activities (p < 0.05). Moreover, FMT ameliorated HFD-induced intestinal architectural damage, as evidenced by significant increases in villus height and the villus height-to-crypt depth ratio (V/C) (p < 0.05). At the molecular level, FMT significantly downregulated the expression of pro-inflammatory cytokines (IL-1β, IL-1α, TNF-α) and upregulated key tight junction proteins (Occludin, Claudin-1, ZO-1) and mucin-2 (MUC2) relative to the HDG (p < 0.05). 16S rRNA analysis demonstrated that FMT substantially increased the abundance of beneficial genera such as Lactobacillus and Bifidobacterium while reducing opportunistic pathogens including Romboutsia (p < 0.05). Furthermore, alpha diversity indices (Chao1 and ACE) were significantly higher in the FMT group than in all other groups (p < 0.05), indicating enhanced microbial richness and community stability. Functional prediction using PICRUSt2 revealed that FMT-enriched metabolic pathways (particularly those associated with SCFA production) and enhanced gut barrier-related functions. Collectively, this study deepens our understanding of host–microbe interactions under HFD-induced metabolic stress and provides mechanistic insights into how FMT restores gut homeostasis, highlighting its potential as a therapeutic strategy for diet-induced dysbiosis and associated metabolic disorders. Full article

Background/Objectives: Maternal immune activation (MIA) increases the risk of Autism Spectrum Disorders (ASD). Experimental models demonstrate that maternal exposure to bacterial endotoxin or the viral mimic polyinosinic:polycytidylic acid [poly (I:C)] reliably recapitulates ASD-like behavioral abnormalities in offspring, yet the underlying neurobiological mechanisms linking MIA to altered neurodevelopment remain incompletely understood. Increasing evidence highlights the placenta as a critical mediator in shaping fetal brain development through immunological and hormonal regulation. Likewise, disruption of placental regulatory functions upon MIA may therefore represent a mechanistic pathway. Here, we investigated how alterations in placental cytokine profiles, innate immune cell composition, and endocrine outputs relate to neuroinflammation and neurogenesis in the offspring. Methods: Pregnant mice at gestational day 12.5 received a single intraperitoneal injection of poly (I:C). Placental macrophages, neutrophils, inflammatory cytokines, and nerve growth factor (NGF) expression were examined 72 h later. Neurodevelopmental outcomes, including microglial activity and neurogenic markers, were evaluated in mouse offspring at postnatal day (P) 1 and 6. Results: MIA induced a significant accumulation of monocytes and neutrophils in the placenta, which was associated with elevated levels of a broad spectrum of inflammatory mediators, including Th17-biased proinflammatory cytokines, chemokines, and adhesion proteins, in the placenta and amniotic fluid. In contrast, the placenta-derived NGF levels were significantly reduced. MIA induced strong and sustained microglial activation in the fetal and neonatal brain. This inflammatory milieu was accompanied by disrupted cortical neurogenesis, characterized by a marked increase in Ki67+ neuronal progenitor cells (NPCs) in the subventricular zone (SVZ), overproduction of early-born Tbr1+ neurons at P1, later-born Satb2+ neurons at P6. Conclusions: Collectively, these findings suggest that heightened Th17 inflammatory signaling, coupled with impaired placental endocrine function, contributes to dysregulated cortical neurogenesis in the offspring. Full article

Lipid A is a component of lipopolysaccharide (LPS) of Gram-negative bacteria. Previously, we demonstrated that synthesized lipid A derived from Alcaligenes faecalis (ALA) could enhance antigen-specific immunoglobulin (Ig) A and T helper (Th) 17 responses, when ALA was co-administered experimentally with an antigen as a vaccine adjuvant. This raised concerns about the safety of the ALA usage, since IgA and Th17 responses have been suggested to play a pathogenic role in several immune-mediated diseases, including multiple sclerosis (MS). We investigated whether ALA administrations could exacerbate an animal model of MS, Theiler’s murine encephalomyelitis virus (TMEV) infection. TMEV-infected SJL/J mice were administered ALA at various time points, and their neurological signs were observed for 7 weeks. We found that ALA administrations did not exacerbate TMEV-induced inflammatory disease or viral persistence in the central nervous system (CNS), clinically or histologically. Furthermore, ALA administrations did not enhance TMEV-specific humoral and cellular responses, including IgA and Th17 responses. On the other hand, principal component analysis (PCA) of the fecal, not the ileal, samples showed significant changes in the microbiota, characterized by increases in the relative abundance of bacteria belonging to the phylum Bacteroidota, including the genera Alistipes and Bacteroides. Therefore, ALA injections could be safe for use in immune-mediated diseases, whose immunopathology has been associated with IgA and Th17 responses. Full article

Background/Objectives: Epilepsy is characterized by unpredictable seizures and drug resistance, along with rising antimicrobial resistance (AMR), highlighting the urgent need for innovative dual-action therapies. This study aimed to design, develop, and evaluate novel pyrazolone derivatives for a dual antimicrobial and antiepileptic potential. Methods: Novel pyrazolone derivatives were designed, synthesized (using 2,4-dinitrophenylhydrazine/semicarbazide condensation with ethyl acetoacetate), and evaluated through molecular docking against antimicrobial (4URM, 3FYV, 3FRA) and neuronal targets (4COF, 5TP9, 5L1F). The in vitro antimicrobial activity was assessed against Gram-positive (S. aureus) and in vitro Gram-negative (E. coli, P. aeruginosa) strains via agar cup plate assays, while in vivo antiepileptic efficacy was tested in a PTZ-induced seizure model in Swiss albino mice. Results: Compound IIa showed potent dual activity, inhibiting E. coli (9 mm zone at 80 μg/mL) and S. aureus (9.5 mm at 80 μg/mL), alongside a significantly delayed seizure onset in the PTZ-induced mouse model (100% survival rate, 45 sec delayed seizure onset, p < 0.001). Compounds Ia and Id showed selective activity against E. coli (6 mm at 80 μg/mL) and P. aeruginosa (7 mm at 80 μg/mL), respectively. Docking studies revealed that compound IIa has a superior binding affinity (−7.57 kcal/mol for 3FYV) compared to standards, driven by hydrogen bonds (SER X: 49) and hydrophobic interactions (LEU X: 20). Conclusions: This study presents a novel approach by proposing a rationally designed pyrazolone scaffold exhibiting both antimicrobial and antiepileptic activity, which integrates in silico modeling with experimental validation. Compound IIa emerged with preliminary dual biological activities, exhibiting strong antibacterial activity, a superior binding affinity toward both bacterial and neuronal targets, and notable seizure prevention in vivo. These findings show the potential of multifunctional pyrazolone derivatives as a new treatment strategy for addressing drug-resistant infections linked to epilepsy and support further optimization toward clinical development. Full article

Objectives: This study evaluated the effects of modified Gamchogeongang-tang (GGS01) on lung injury using a COPD mouse model. Methods: C57BL/6 mice were exposed to cigarette smoke extract and lipopolysaccharide and treated with GGS01 (100, 200, or 400 mg/kg). Bronchoalveolar lavage fluid (BALF) and lung tissue were analyzed using cytospin, enzyme-linked immunosorbent assay, real-time polymerase chain reaction (PCR), flow cytometry analysis, hematoxylin and eosin (H&E) and Masson’s trichrome staining, and immune histology fluorescent staining. Results: GGS01 significantly inhibited the increase in neutrophils in BALF, decreased immune cell activity in BALF and lung tissue, and inhibited the increase in the levels of IL-1α, TNF-α, IL-17A, MIP2, and CXCL-1 in BALF. Conclusions: Real-time PCR analysis showed that MUC5AC mRNA expression in lung tissue significantly decreased compared with the control group. The score of histological analysis of lung tissue damage was significantly reduced, and a decrease in IRAK1 and TNF-α expression in lung tissue was observed. Full article

Major depressive disorder (MDD) is a leading cause of global morbidity and mortality. Although pharmacological treatments are widely used, their effects are often limited, and nearly half of patients show resistance to current antidepressants, including those unresponsive to all available therapies. These challenges highlight the need to better understand the neurobiological mechanisms driving MDD and to develop novel therapeutic strategies, especially those involving natural compounds with multitarget actions. Baicalin, a bioactive flavonoid from Scutellaria baicalensis, exhibits antioxidant, anti-inflammatory, and neuroprotective properties and has recently gained attention for its potential to improve cognitive deficits and mood disorders. In this study, we investigated baicalin’s antidepressant potential and its underlying mechanisms across multiple experimental levels. We found that oral administration of baicalin produced antidepressant-like effects in both naïve mice and those subjected to chronic restraint stress (CRS). CRS impaired hippocampal long-term potentiation (LTP), whereas baicalin restored these synaptic deficits. Importantly, intra-dorsal hippocampal microinjection of the TrkB receptor antagonist ANA-12 abolished baicalin’s antidepressant effects, indicating the involvement of BDNF–TrkB signaling. Baicalin also reduced reactive oxygen species (ROS)/H₂O₂ production in a BDNF-associated manner, demonstrating clear antioxidant activity. Molecular docking further suggested that baicalin binds more effectively to the TrkB receptor than ANA-12, supporting its capacity to activate TrkB-mediated signaling. By integrating in vivo, ex vivo, in vitro, and in silico approaches, our study shows that baicalin exerts robust antioxidant in vitro and antidepressant effects in vivo. These benefits are primarily mediated through activation of BDNF–TrkB signaling, leading to reduced ROS/H₂O₂ accumulation and alleviation of CRS-induced depression-like behaviors. Full article

Laboratory mice are the most widely used model organisms in biomedical and behavioral research, yet growing concerns regarding reproducibility and translational validity have highlighted the substantial influence of housing and husbandry conditions on experimental outcomes. Although domestication is often assumed to have rendered laboratory mice fully adapted to artificial environments, evidence from ethology indicates that many core behavioral and physiological needs remain conserved. As a result, standard laboratory housing may generate chronic stress, alter behavior, and introduce systematic bias into experimental data. This narrative review critically examines how ethological constraints persisting after domestication interact with key environmental factors, social housing, environmental enrichment, ambient temperature, and lighting regimes to shape welfare and experimental validity in laboratory mice. Rather than providing an exhaustive overview of mouse behavior, the review adopts a problem-oriented and solution-focused approach, highlighting specific welfare-related mechanisms that can distort behavioral and physiological readouts. Particular attention is given to social isolation and aggression in male mice, the role of nesting material in mitigating thermal stress, and the effects of circadian disruption under standard and reversed light–dark cycles. By integrating ethological theory with laboratory animal welfare research, this review argues that housing conditions should be regarded as integral components of experimental design rather than secondary technical variables. Addressing welfare-related bias through evidence-based refinement strategies is essential for improving reproducibility, enhancing data interpretability, and strengthening the scientific validity of mouse-based research. Full article

Background: Pulmonary fibrosis (PF) currently lacks effective therapeutic interventions. Roxadustat, an oral small-molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase, has been shown in several studies to attenuate the progression of fibrotic diseases. However, its therapeutic efficacy in PF remains to be fully elucidated. The aim of this study was to evaluate roxadustat’s therapeutic benefits on PF as well as the underlying mechanisms of action. Methods: Bleomycin was administered intraperitoneally to establish a PF mouse model. H&E staining, Masson staining, and immunohistochemistry (IHC) were used to assess histopathological and fibrotic changes. Changes in the expression levels of inflammatory mediators, including IL-1β, TGF-β1, and TNF-α, were examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Network pharmacology combined with transcriptomic analysis was employed to identify potential target genes and associated signaling pathways. Subsequently, RT-qPCR and Western blot analyses were carried out to experimentally validate the predicted targets and pathways and to verify the protective effects of roxadustat in PF mice. Results: Roxadustat markedly ameliorated bleomycin-induced pulmonary fibrosis in mice. The therapeutic effect was evidenced by a reduction in alveolar damage, thinner alveolar septa, diminished infiltration of inflammatory cells, and decreased collagen deposition. Concomitantly, the expression levels of inflammatory mediators, including IL-1β, TGF-β1, and TNF-α, were significantly lowered. Integrated network pharmacology and transcriptomic analyses revealed the involvement of critical signaling pathways, specifically nuclear factor-kappa B (NF-κB) and peroxisome proliferator-activated receptor (PPAR). Experimental validation further demonstrated that roxadustat downregulated the expression of key genes (S100A8, S100A9, and Fos) in murine lung tissues. It also suppressed the protein ratios of phosphorylated p65 to total p65 and phosphorylated IκBα to total IκBα. Moreover, roxadustat treatment upregulated PPARγ protein expression. Conclusions: These data indicate that roxadustat ameliorates bleomycin-induced PF in mice, an effect associated with modulation of the NF-κB and PPAR signaling pathways. The findings provide a preclinical rationale for further investigation of roxadustat as a potential treatment for PF. Full article

Background/Objectives: Inter-individual variability in injury severity represents a major barrier to reproducibility in neonatal hypoxia–ischemia (HI) models. Objective early postoperative stratification of animals is therefore essential for standardized group allocation and reliable assessment of experimental outcomes. This study aimed to evaluate whether laser speckle contrast imaging (LSCI) can be used as a rapid, noninvasive tool for early post hoc stratification of ischemic brain damage severity in neonatal mice following HI. Methods: Neonatal CD-1 mice (postnatal day 9; n = 60) underwent hypoxia–ischemia using a modified Rice–Vannucci protocol. Cerebral perfusion was assessed by laser speckle contrast imaging at baseline, 3 h, and 7 days after HI. The difference in mean perfusion between ipsilateral and contralateral hemispheres at 3 h (Δ perfusion) was used to stratify animals into severity groups. Brain injury was quantified by 2,3,5-triphenyltetrazolium chloride (TTC) staining at 24 h and 7 days. Survival was monitored for 7 days and analyzed using Kaplan–Meier curves and the log-rank (Mantel–Cox) test. Results: LSCI-derived Δ perfusion at 3 h enabled the formation of distinct injury-severity groups (no visible damage, mild, moderate, and severe) with significant between-group differences (p < 0.0001). TTC-based lesion area increased stepwise across severity groups, and Δ perfusion correlated with lesion size when all animals were analyzed together (r = 0.688, p = 0.0011). No significant correlations were observed within individual severity groups, indicating that the overall association was driven primarily by between-group differences. Survival analysis revealed 75% mortality in the severe injury group (p < 0.0001). Conclusions: LSCI represents a robust and practical approach for early, objective, group-level stratification of neonatal mice by HI injury severity, thereby improving reproducibility and statistical validity in preclinical studies. However, its ability to predict outcomes within individual severity categories is limited, and repeated long-term measurements may pose technical challenges. Full article

Immune checkpoint inhibitors (ICIs) for cancer therapy may induce immune-related adverse events including myocarditis, which occurs infrequently but carries a high mortality rate. Crocins are the active constituents derived from Crocus sativus L. (saffron), and have demonstrated various bioactivities including anti-tumor, anti-inflammation, antioxidation, anti-ischemia, anti-aging, and neuroprotective effects. This study established a subcutaneous xenotransplanted tumor model of human liver cancer in nude mice to better mimic ICI-related myocarditis. Animal experimental results revealed that crocins improved cardiac function, relieved myocardial damage and autoimmune response, and suppressed oxidative stress and inflammatory reaction. Quantitative proteomics and Western blotting verification confirmed that crocins ameliorated experimental ICI-related myocarditis by targeting the Hpx/Nrf2/HO-1 pathway. Molecular docking revealed that the best docking activities were demonstrated by crocin I–HO-1, crocin II–Hpx, and crocin III–Nrf2. These findings shed new light on the development of therapeutic strategies for treating ICI-related myocarditis and provided the fundamental basis for expanding the clinical application of crocins. Full article

Background/Objectives: Neurodegenerative diseases are driven by multiple interconnected pathological mechanisms involving both intrinsic and extrinsic molecular and cellular processes. Efficient bidirectional intracellular transport is essential for neuronal survival and function, enabling the movement of organelles, proteins, and vesicles between the neuronal soma and distal compartments. This process is primarily mediated by kinesin-dependent anterograde transport and dynein-dependent retrograde transport. Disruption of either motor protein compromises endosome–lysosome recycling, leading to cellular dysfunction and neurodegeneration. However, the mechanisms underlying motor protein impairment in Parkinson’s disease (PD) remain incompletely understood. Methods: We investigated the involvement of kinesin and dynein in intracellular transport dysfunction using both in vitro and in vivo models of PD. Cultured neuronal cells were exposed to MPP+ (1-methyl-4-phenylpyridinium) to model PD-associated neurotoxicity, and motor protein function, vesicular trafficking, and endosomal recycling were assessed. In parallel, an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD was used to evaluate dynein-positive fiber density in the spinal cord. The role of calpain-2 was examined by co-treatment with the selective calpain-2 inhibitor zLLYCH2F in both experimental systems. Results: MPP+ exposure disrupted kinesin- and dynein-mediated transport in neuronal cytoplasm, resulting in impaired vesicular trafficking and defective endosome–lysosome recycling. These alterations led to abnormal accumulation of vesicles in both perinuclear regions and at the cell periphery. Pharmacological inhibition of calpain-2 with zLLYCH2F restored motor protein function and normalized vesicle distribution in MPP+-treated cells. Consistent with in vitro findings, MPTP-treated mice exhibited a significant reduction in dynein-positive fiber density within the spinal cord, which was prevented by co-treatment with zLLYCH2F. Conclusions: Our findings demonstrate that calpain-2 activation contributes to kinesin and dynein dysfunction following MPP+/MPTP exposure, leading to impaired intracellular transport and vesicle recycling in PD models. Inhibition of calpain-2 preserves motor protein function, maintains cytoskeletal integrity, and supports normal intracellular trafficking. These results identify calpain-2 as a critical regulator of motor protein stability and suggest that targeting calpain-2 may represent a promising therapeutic strategy for mitigating intracellular transport defects in Parkinson’s disease. Full article