Search Results (248)

Background/Objective: Parkinson’s disease (PD) has long been viewed from a neurocentric perspective; however, increasing evidence indicates that glial dysfunction also contributes to dopaminergic neurodegeneration. Although neurotoxic glial phenotypes have been described in amyotrophic lateral sclerosis and Alzheimer’s disease in vivo models, it remains unclear whether similar states arise in the pathological milieu of PD. This study aimed to determine whether glial cells with intrinsic neurotoxic properties emerge in the substantia nigra pars compacta (SNpc) in a PD context. Methods: The classical 6-hydroxydopamine rat model was used to obtain glial cultures from the ipsilateral, toxin-damaged SNpc. These cultures were characterized by quantifying cell number and morphology, as well as by assessing the expression of glial markers. Their neurotoxic potential was evaluated in vitro through co-cultures with PC12 cells, and in vivo by transplanting the isolated cells into the SNpc of naïve rats. Assessments included PC12 cell survival, and integrity of the nigrostriatal pathway and motor performance in the cylinder test. Results: Ipsilateral SNpc cultures yielded 25-fold more cells than contralateral controls. Cultured cells co-expressed astrocytic and microglial markers, thus defining a population of damage-derived reactive glia (DDRG). When co-cultured, DDRG reduced PC12 cell survival, whereas control glial cells showed no neurotoxic effects. In vivo, DDRG transplantation induced a dose-dependent loss of dopaminergic neurons and motor impairments, while vehicle and control glia produced no detectable effects. Conclusions: Our findings suggest that glial cells emerging from a neuroinflammatory/neurodegenerative environment in the SNpc may contribute to dopaminergic neuron loss. Within the context of the experimental PD model used, DDRG appears to represent a glial population with potential pathogenic relevance and may constitute a candidate target for further investigation as a therapeutic strategy in Parkinson’s disease. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the selective loss of dopaminergic (DAergic) neurons in the substantia nigra (SN) and the accumulation of misfolded α-synuclein (aSyn). In addition to neuronal pathology, activated microglia are recognized as key mediators of the neuroinflammatory milieu in PD, contributing to DAergic neuron vulnerability. Emerging evidence suggests that the immune system, particularly T-cell-mediated responses, plays a key role in the pathogenesis of PD. However, the heterogeneity of these immune responses across species and preclinical models with varying regenerative capacities remains poorly understood. A comparative analysis of T-cell infiltration, astroglial reactivity, and DAergic neuronal loss across multiple models and species was performed. These included acute DAergic degeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), genetically modified mice with accumulation of aSyn (Thy1-aSyn L61 model), adult zebrafish exposed to MPTP-induced neurotoxicity and human post-mortem midbrain tissue obtained from PD patients. Zebrafish exhibited transient DAergic neurodegeneration, followed by neuronal regeneration and temporary CD4⁺ T-cell infiltration accompanied by an astroglial response and activation of microglia. In contrast, MPTP-treated mice showed a permanent neuronal loss, marked microglial activation, increased astrogliosis and CD8⁺ T-cell infiltration that was negatively correlated with neuronal survival. By contrast, L61 mice exhibited progressive aSyn accumulation with chronic astrogliosis, mild activation of microglia and CD4⁺ T-cell infiltration not directly linked to neuronal loss. Unlike age-matched controls, the SN from PD brains exhibited DAergic degeneration, aSyn aggregation, and elevated CD3⁺ T-cell infiltration, and increased microglial activation. These changes correlated with neuronal loss and aSyn burden. These findings emphasize the species- and model-specific immune profiles underlying PD pathology. Our results reveal that CD4⁺ T-cells contribute to neuronal regeneration following injury in zebrafish. This process is absent in the MPTP and L61 mouse models, which are instead driven by CD8⁺ or CD4⁺, respectively. This work underscores the potential of targeted immunomodulation aimed at T cell–glial interactions to slow neurodegeneration and promote repair in PD. Full article

Parkinson’s disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra and pathological α-synuclein aggregation. Growing evidence identifies chronic neuroinflammation—particularly NLRP3 inflammasome activation in microglia—as a central driver for PD onset and progression. Misfolded α-synuclein, mitochondrial dysfunction, and environmental toxins act as endogenous danger signals that prime and activate NLRP3 inflammasome, leading to caspase-1–mediated maturation of IL-1β and IL-18 and subsequent pyroptotic cell death. Impaired mitophagy, due to defects in PINK1/Parkin pathways or receptor-mediated mechanisms, permits accumulation of dysfunctional mitochondria and release DAMPs, thereby amplifying NLRP3 activity. Studies demonstrate that promoting mitophagy or directly inhibiting NLRP3 attenuates neuroinflammation and protects dopaminergic neurons in PD models. Autophagy-inducing compounds, along with NLRP3 inhibitors, demonstrate neuroprotective potential, though their clinical translation remains limited due to poor blood–brain barrier penetration, off-target effects, and insufficient clinical data. Additionally, the context-dependent nature of mitophagy underscores the need for precise therapeutic modulation. This review summarizes current understanding of inflammasome–mitophagy crosstalk in PD, highlights major pharmacological strategies under investigation, and outlines its limitations. Future progress requires development of specific modulators, targeted delivery systems, and robust biomarkers of mitochondrial dynamics and inflammasome activity for slowing PD progression. Full article

Evidence increasingly indicates that synaptic vesicle dysfunction emerges early in Parkinson’s disease (PD), preceding overt dopaminergic neuron loss rather than arising solely as a downstream consequence of neurodegeneration. α-Synuclein (αSyn), a presynaptic protein that regulates vesicle clustering, trafficking, and neurotransmitter release under physiological conditions, exhibits dose-, conformation-, and context-dependent actions that distinguish its normal regulatory roles from pathological effects observed in disease models. This narrative review synthesizes findings from a structured search of PubMed and Scopus, with emphasis on α-syn-knockout (αSynKO) and BAC transgenic (αSynBAC) mouse models, which do not recapitulate the full human PD trajectory but provide complementary insights into αSyn physiological function and dosage-sensitive vulnerability. Priority was given to studies integrating ultrastructural approaches—such as cryo-electron tomography, high-pressure freezing/freeze-substitution TEM, and super-resolution microscopy—with proteomic and lipidomic analyses. Across these methodologies, several convergent presynaptic alterations are consistently observed. In vivo and ex vivo studies associate αSyn perturbation with impaired vesicle acidification, consistent with altered expression or composition of vacuolar-type H⁺-ATPase subunits. Lipidomic analyses reveal age- and genotype-dependent remodeling of vesicle membrane lipids, particularly curvature- and charge-sensitive phospholipids, which may destabilize αSyn–membrane interactions. Complementary biochemical and cell-based studies support disruption of SNARE complex assembly and nanoscale release-site organization, while ultrastructural analyses demonstrate reduced vesicle docking, altered active zone geometry, and vesicle pool disorganization, collectively indicating compromised presynaptic efficiency. These findings support a synapse-centered framework in which presynaptic dysfunction represents an early and mechanistically relevant feature of PD. Rather than advocating αSyn elimination, emerging therapeutic concepts emphasize preservation of physiological vesicle function—through modulation of vesicle acidification, SNARE interactions, or membrane lipid homeostasis. Although such strategies remain exploratory, they identify the presynaptic terminal as a potential window for early intervention aimed at maintaining synaptic resilience and delaying functional decline in PD. Full article

Parkinson’s disease (PD) is a neurodegenerative pathology defined by specific, distinctive signs, primarily the progressive loss of dopaminergic neurons (DAergic) in the substantia nigra pars compacta (SNpc), associated with gliosis phenomena. The mechanisms that trigger the degeneration of DAergic neurons are not yet fully elucidated, although it is recognized that the interaction between genetic and environmental factors acts as a critical modulator of neuronal vulnerability. Strong evidence points to glial reactivity as a central element in PD pathophysiology; however, it remains a controversial topic whether this activation has a protective effect or, on the contrary, whether it contributes to exacerbating DAergic neuronal loss. The use of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)—a neurotoxic substance—represented a turning point in Parkinson’s research, allowing the clarification of various molecular mechanisms of the disease. The primary aim of this review is to explore the current state of knowledge regarding the role of astrocytes in the processes of DAergic neurodegeneration, neuroprotection, and neurorepair. We focused on the relationship between astrocytic origin factors and neurogenic signals that mediate MPTP-induced plasticity in DAergic neurons of the nigrostriatal system. The contribution of reactive astrocytes in promoting DAergic neurogenesis starting from Neural Stem/Progenitor Cells (NPCs) present in the adult midbrain is also analyzed. Among the mediators released by astrocytes, we have previously identified the Wnt/β-catenin signaling pathway as a fundamental element capable of positively influencing neuroplasticity and dopaminergic neuronal repair induced by the toxic MPTP. In conclusion, deciphering the intrinsic plasticity of nigrostriatal DAergic neurons and signals that facilitate communication between astrocytes and NPCs is crucial for the identification of potential therapeutic targets aimed at stimulating neuronal repair. Full article

Background/Objectives: Parkinson’s disease (PD) is the second most common neurodegenerative disease (NDD), marked by the progressive loss of dopaminergic neurons in the substantia nigra that causes motor dysfunction. Growing evidence indicates that neuroinflammation plays a crucial role in the onset and progression of PD, though the exact mechanisms are still unclear. In this study, we examined the anti-inflammatory and neuroprotective effects of 4-[3-oxo-3-(2-trifluoromethyl-phenyl)-propyl]-morpholinium chloride (OTPM), a fluoxetine derivative and selective serotonin reuptake inhibitor, in both lipopolysaccharide (LPS)-stimulated BV-2 microglial cells and an MPTP-induced mouse model of PD. Methods: C57BL/6 mice were orally administered OTPM (10 mg/kg b.w.) for 7 days and intraperitoneally injected with MPTP (20 mg/kg b.w.) for one day, with four injections at 2 h intervals. Bradykinesia was assessed using the Y-maze and Pole tests. Protein and mRNA levels were examined in vitro and in vivo using Western blotting and RT-PCR. Immunofluorescence was used to assess microglial and astrocyte activation. Results: In vitro, OTPM significantly decreased nitric oxide (NO) production (p < 0.001) and suppressed the protein and mRNA expression of iNOS (p < 0.001), COX-2 (p < 0.001), and pro-inflammatory cytokines, including IL-β (p < 0.001), IL-6 (p < 0.001), and TNF-α (p < 0.01), in LPS-activated BV-2 microglia. Further mechanistic studies showed that OTPM inhibited NF-κB phosphorylation and blocked its nuclear translocation, thereby reducing inflammatory signaling. In vivo, treatment with OTPM (10 mg/kg for 7 days) significantly reduced the MPTP-induced activation of microglia (MAC-1) and astroglia (GFAP) in the brain and improved behavioral deficits associated with PD, as assessed in the Y-maze and pole tests. Conclusions: Overall, these results reveal that OTPM has strong anti-neuroinflammatory and neuroprotective properties, suggesting its potential as a new therapeutic candidate for PD and other disorders associated with neuroinflammation. Full article

Background: Alpha-synuclein is a key protein involved in the pathogenesis of Parkinson disease (PD). Its intermediate aggregated forms disturb the normal function of dopaminergic (DA) neurons. Furthermore, the loss of intraneuronal connections may precede nerve cell death in PD. Disturbance of presynaptic functions of alpha-synuclein and its family members, beta- and gamma-synuclein, can apparently be the first step in nigrostriatal system dysfunction. Based on their structure homology and subcellular localization, the three synuclein proteins could have overlapping functions. This also indicates necessitates to study each protein in isolation. Methods: We have established a unique mouse line with conditional knockout (KO) of alpha-synuclein inactivation on the background of gamma-synuclein KO. Results: During the early phase of alpha-synuclein loss of function, mice demonstrate reduced explorer activity, decreased gene expression of Mao-B in the midbrain, and transiently increased levels of beta-synuclein protein in the striatum after alpha-synuclein inactivation, as results, metabolism of dopamine stays unscathed. These changes can be caused by specific regulation of Mao-B by alpha-synuclein or can be a physiological reaction aimed at restoring alpha-synuclein levels. No significant changes in gene expression patterns of dopamine-related enzymes in the midbrain or protein levels in the striatum and midbrain were observed. Conclusions: Our data suggest that sudden alpha-synuclein depletion leads to an increase in beta-synuclein levels, likely as functional replacement. This result supports that beta-synuclein can compensate the loss of alpha-synuclein. In general, this process may characterize synapse reconstruction in early alpha-synuclein dysfunction with gamma-synuclein absence and form the basis for replacement therapeutic strategies in PD. Full article

Various clinical studies aimed at modifying the progression of idiopathic Parkinson’s disease have been unsuccessful. Similarly, several nutritional trials using bioactive compounds have shown positive effects for patients but have also failed to slow or reduce the disease’s progression. This repeated failure is likely because these studies ignore the extremely slow neurodegenerative process, which unfolds over many years. The molecular mechanism behind the loss of neuromelanin-containing dopaminergic neurons in the nigrostriatal system in idiopathic Parkinson’s disease remains unclear. This is a conceptual/theoretical review based mainly on mechanistic and preclinical evidence, with no direct clinical data. However, research suggests that aminochrome, an endogenous neurotoxin, may trigger the degeneration of these neurons through a single-neuron degeneration model. In this model, aminochrome selectively destroys individual neurons without spreading to neighboring cells. Aminochrome is produced during neuromelanin synthesis, a process that is normally harmless because protective enzymes like DT-diaphorase and glutathione transferase M2-2 neutralize aminochrome’s neurotoxic effects. Increasing the levels of these enzymes could offer neuroprotection. The KEAP1/NRF2 signaling pathway is critical for regulating antioxidant enzymes, such as DT-diaphorase and glutathione transferase M2-2. Importantly, specific bioactive compounds from food can activate this pathway, increasing the production of these protective enzymes. For instance, the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), along with astaxanthin—a compound present in cold-water fish like salmon—have been demonstrated to enhance enzyme expression. This connection leads to a compelling question: Could dietary interventions help prevent idiopathic Parkinson’s disease? Answering this will require further research. Full article

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disorder characterized by progressive demyelination and axonal degeneration within the central nervous system, driven by complex genomic and epigenomic dysregulation. Its pathogenesis involves aberrant DNA methylation patterns at CpG islands of numbers of genes like OLIG1 and OLIG2 disrupting protein expression at myelin with compromised oligodendrocyte differentiation. Furthermore, histone modifications, particularly H3K4me3 and H3K27ac, alter the promoter regions of genes responsible for myelination, affecting myelin synthesis. MS exhibits chromosomal instability and copy number variations in immune-regulatory gene loci, contributing to the elevated expression of genes for pro-inflammatory cytokines (TNF-α, IL-6) and reductions in anti-inflammatory molecules (IL-10, TGF-β1). Vitamin D deficiency correlates with compromised immune regulation through hypermethylation and reduced chromatin accessibility of vitamin D receptor (VDR) dysfunction and is reported to be associated with dopaminergic neuronal loss. Vitamin D supplementation demonstrates therapeutic potential through binding with VDR, which facilitates nuclear translocation and subsequent transcriptional activation of target genes via vitamin D response elements (VDREs), resulting in suppression of NF-κB signalling, enhancement of regulatory T-cell (T_reg) responses due to upregulation of specific genes like FOXP3, downregulation of pro-inflammatory pathways, and potential restoration of the chromatin accessibility of oligodendrocyte-specific gene promoters, which normalizes oligodendrocyte activity. Identification of differentially methylated regions (DMRs) and differentially expressed genes (DEGs) that are in proximity to VDR-mediated gene regulation supports vitamin D supplementation as a promising, economically viable, and sustainable therapeutic strategy for MS. This systematic review integrates clinical evidence and eventual bioinformatical meta-analyses that reference transcriptome and methylome profiling and identify prospective molecular targets that represent potential genetic and epigenetic biomarkers for personalized therapeutic intervention. Full article

Parkinson’s disease (PD) is a disabling neurodegenerative disorder that is defined by progressive loss of dopaminergic neurons in the substantia nigra, deposition of α-synuclein aggregates, and chronic neuroinflammation. While symptomatic therapies have evolved, disease-modifying therapies remain elusive. Extracellular vesicles (EVs), particularly those derived from mesenchymal stem cells (MSC-EVs), have emerged as promising therapeutic agents because they possess a natural ability to cross the blood–brain barrier and deliver bioactive cargo. Herein, we review the dual-edged function of EVs in PD pathogenesis: facilitating the transfer of toxic α-synuclein while also conferring neuroprotective signals through MSC-EVs. We outline the mechanisms of MSC-EV-mediated neuroprotection that include the regulation of oxidative stress, neuroinflammation, and autophagy. We also emphasize new nanocarrier systems designed to bypass delivery challenges in PD therapy. While preclinical studies are extremely encouraging, significant issues regarding scalability, standardization, and clinical translation must be resolved before realizing the ultimate therapeutic potential of EV-based and nanocarrier-based approaches to PD. Full article

Background/Objectives: Glutamatergic neurotransmission is essential for the normal functioning of the retina. Photoreceptor to bipolar and bipolar to ganglion cell signaling is mediated by L-glutamate, which is stored in and released from vesicular glutamate transporter 1 (VGLUT1) containing synaptic vesicles. VGLUT1 is expressed postnatally, P2 onwards, and is required for the glutamatergic retinal wave observed between P10 and P12 in the developing mouse retina. P9–P13 postnatal age is critical for retinal development as VGLUT1 expressing ribbon synapses activate in the outer and inner plexiform layers, and rod/cone mediated visual signaling commences in that period. Although it has been hypothesized that glutamatergic extrinsic signaling drives cell cycle exit and initiates cellular differentiation in the developing retina, it is not clear whether intracellular, synaptic, or extrasynaptic vesicular glutamate release contributes to this process. Recent studies have attempted to decipher VGLUT’s role in retinal development. Here, we investigate the potential effect of genetic loss of VGLUT1 on early postnatal histogenesis and development of retinal neural circuitry. Methods: We employed immunohistochemistry and electrophysiology to ascertain the density of glutamatergic, cholinergic, and dopaminergic cells, spontaneous retinal activity, and light responses in VGLUT1 null retina, and contrasted them with wildtype (WT) and melanopsin null retina. Results: We have demonstrated here that VGLUT1 null retina shows signs of age dependent retinal degeneration, similar to other transgenic mice models with dysfunctional photoreceptor to bipolar cell synapses. The loss of VGLUT1 specifically alters glutamatergic cell density and morphological maturation of retinal ganglion cells. Moreover, VGLUT2 expression is lost in the majority of VGLUT2 cones in the absence of VGLUT1 coexpression, except when VGLUT2 coexpresses transiently with VGLUT3 in these cones, or when VGLUT1 null mice are dark reared. Conclusions: We present the first evidence that synaptic or extrasynaptic postnatal glutamate release from VGLUT1 containing vesicles impacts histogenesis of glutamatergic cells, pruning of retinal ganglion cell dendrites and VGLUT2 expression in cones. Full article

Selective proteasome inhibitors, used to model Parkinsonian-like pathology, are known to disrupt calcium homeostasis, but the role of calcium ions in dopaminergic neuron degeneration remains unclear. The present in vivo study examined the effects of a 7-day intraperitoneal administration of cinnarizine (10 or 30 mg/kg), a voltage-gated calcium channel blocker, in rats unilaterally injected into the substantia nigra compacta (SNc) with lactacystin (Lac; 1 µg/2 µL) or vehicle. Dopamine (DA) and its metabolites were quantified in striatal homogenates via high-performance liquid chromatography. The SN of rats treated with 10 mg/kg cinnarizine was used for Western blot analysis of tyrosine hydroxylase (TH), while tissue from animals receiving 30 mg/kg was processed for histological analysis of TH-immunoreactive (TH-ir) and cresyl violet (CV)-stained neurons. Significant reductions in striatal DA and its metabolites were observed one week after Lac injection, along with increased DA catabolism. Cinnarizine at both doses partially prevented DA loss and attenuated enhanced DA turnover. Moreover, 10 mg/kg cinnarizine partially preserved TH protein levels, while 30 mg/kg provided histological protection of TH-ir neurons in the SN. Cinnarizine was also tested in vitro in human SH-SY5Y neuroblastoma cells and primary mouse cortical neurons exposed to Lac or rotenone to further assess its neuroprotective potential. In SH-SY5Y cells, cinnarizine (1–10 µM) significantly increased cell viability and reduced lactate dehydrogenase release after toxin exposure. Cinnarizine failed to counteract lactacystin-induced toxicity in primary cortical neurons but markedly reduced rotenone-evoked cell death at similar concentrations. These findings indicate that cinnarizine exerts dose-dependent neuroprotective effects in vivo and selective protective actions in vitro, supporting the potential utility of voltage-gated calcium channel blockers in treating Parkinson’s disease. Full article

Parkinson’s disease (PD) is recognized as one of the most common neurodegenerative disorders globally. The primary factor contributing to this condition is the loss of dopaminergic neurons, which results in both motor and nonmotor symptoms. The etiology of neurodegeneration remains unclear. However, it is characterized by the elevated production of reactive oxygen species, which subsequently leads to oxidative stress, lipid peroxidation, mitochondrial dysfunction, and inflammation. The investigation of the applicability of natural compounds and their derivatives to various diseases is becoming increasingly important. The possible role of curcumin from Curcuma longa L. and its derivatives in the treatment of PD has been partially investigated, but there are no data on the action of synthetic cyclic C₅-curcuminoids and chalcones tested in a Parkinson’s model. Two chalcones and five synthetic cyclic C₅-curcuminoids with potential antioxidant properties were investigated in an in vitro model of 6-hydroxydopamine (6-OHDA)-induced neurodegeneration in differentiated SH-SY5Y cells. Reactive oxygen species (ROS) production, total antioxidant capacity, antioxidant enzyme activity, thiol and ATP levels, caspase-3 activity, and cytokine release were examined after treatment with the test compounds. Based on these results, one cyclic chalcone (compound 5) and three synthetic cyclic C₅-curcuminoids (compounds 9, 12, and 13) decreased oxidative stress and apoptosis in our in vitro model of neurodegeneration. Compounds 5 and 9 were also successful in decreasing the production of pro-inflammatory cytokines (IL-6, IL-8, and TNF-α), while promoting the release of anti-inflammatory cytokines (IL-4 and IL-10). These findings indicate that these two compounds exhibit potential antioxidant, anti-apoptotic, and anti-inflammatory properties, rendering them promising candidates for drug development. Full article

Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra, and key pathways such as neuroinflammation, oxidative stress, and autophagy are believed to significantly contribute to the mechanisms of neurodegeneration. Calpain activation plays a critical role in neuroinflammation and neurodegeneration, as demonstrated by its impact on microglial activation, reactive oxygen species (ROS) production, and neuronal survival. In this study, we investigated the effects of calpain inhibition using calpeptin (CP) and calpain-2-specific inhibitors in cellular and murine models of neuroinflammation and PD. In BV2 microglial cells, LPS-induced production of pro-inflammatory cytokines (TNF-α, IL-6) and chemokines (MCP-1, IP-10) were significantly reduced by CP treatment with a concomitant decrease in ROS generation. Similarly, in VSC-4.1 motoneuron cells, calpain inhibition attenuated IFN-γ-induced ROS production and improved cell viability, demonstrating its neuroprotective effects. Moreover, in a murine MPTP model of PD, calpain inhibition reduced astrogliosis, ROCK2 expression, and levels of inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-7, and IL12p70) and chemokines (MCP-1 and IP-10) in the dorsal striatum and plasma. The specific role of calpain-2 in immune modulation was further highlighted in human microglia, SV-40 cells. With respect to immune modulation in these cells, siRNA-mediated knockdown of calpain-2, but not calpain-1, significantly reduced antigen presentation to CD4+ T cells. Thus, calpain-2 is likely involved in regulating antigen presentation and activation of inflammatory CD4+ T cells. These findings underscore the therapeutic potential of calpain-2 inhibition in mitigating neuroinflammation and neurodegeneration, particularly in PD, by targeting microglial activation, ROS production, and neuronal survival pathways. Full article

Despite the abundant expression of the microRNA-degrading Translin (TN)/Trax (TX) complex in midbrain dopaminergic (DA) neurons and its implication in neuropsychiatric disorders, its cell-autonomous roles in metabolic and behavioral responses remain unclear. To address this, we generated DA neuron-specific conditional knockout (cKO) mice for Tsn (TN) or Tsnax (TX) using DAT-Cre. Immunostaining confirmed efficient TX loss in Tsnax cKO DA neurons without affecting TN, while Tsn deletion abolished TX expression, revealing asymmetric protein dependency. Body composition analysis showed no alterations in adiposity in either cKO model. Locomotor responses to acute or repeated administration of cocaine (20 mg/kg) or amphetamine (2.5 mg/kg) were unchanged in Tsn or Tsnax cKO mice. Furthermore, amphetamine-induced conditioned place preference (1 mg/kg) was unaffected. These results demonstrate that the TN/TX complex within DA neurons is dispensable for regulating adiposity, psychostimulant-induced locomotion (both acute and sensitized), or amphetamine reward-related behavior, suggesting its critical functions may lie outside these specific domains. Full article