Search Results (250)

Multiple sclerosis (MS) is a chronic, immune-mediated disorder of the central nervous system (CNS) characterized by inflammation, demyelination, axonal degeneration, and gliosis. Its pathophysiology involves a complex interplay of genetic susceptibility, environmental triggers, and immune dysregulation, ultimately leading to progressive neurodegeneration and functional decline. Although significant advances have been made in disease-modifying therapies (DMTs), many patients continue to experience disease progression and unmet therapeutic needs. Drug repurposing—the identification of new indications for existing drugs—has emerged as a promising strategy in MS research, offering a cost-effective and time-efficient alternative to traditional drug development. Several compounds originally developed for other diseases, including immunomodulatory, anti-inflammatory, and neuroprotective agents, are currently under investigation for their efficacy in MS. Repurposed agents, such as selective sphingosine-1-phosphate (S1P) receptor modulators, kinase inhibitors, and metabolic regulators, have demonstrated potential in promoting neuroprotection, modulating immune responses, and supporting remyelination in both preclinical and clinical settings. Simultaneously, artificial intelligence (AI) is transforming drug discovery and precision medicine in MS. Machine learning and deep learning models are being employed to analyze high-dimensional biomedical data, predict drug–target interactions, streamline drug repurposing workflows, and enhance therapeutic candidate selection. By integrating multiomics and neuroimaging data, AI tools facilitate the identification of novel targets and support patient stratification for individualized treatment. This review highlights recent advances in drug repurposing and discovery for MS, with a particular emphasis on the emerging role of AI in accelerating therapeutic innovation and optimizing treatment strategies. Full article

The use of Botulinum Neurotoxin A (BoNT/A) to treat peripheral neuropathic pain from nerve injury has garnered interest for its long-lasting effects and safety. This study examined the effects of IncobotulinumtoxinA (Inco/A), a BoNT/A variant without accessory proteins, on nerve regeneration in rats using the chronic constriction injury (CCI) model. Inco/A was administered perineurally at two time points: on days 0 and 21 post CCI. Functional and histological assessments were conducted to evaluate the effect of Inco/A on nerve regeneration. Sciatic Functional Index (SFI) measurements and Compound Muscle Action Potential (CMAP) recordings were conducted at different time points following CCI. Inco/A-treated animals exhibited a 65% improved SFI and 22% reduction in CMAP onset latencies compared to the vehicle-treated group, suggesting accelerated functional nerve recovery. Tissue analysis revealed enhanced remyelination in Inco/A-treated animals and 60% reduction in CGRP and double S100β signal expression compared to controls. Strikingly, 30% reduced immune cell influx into the injury site was observed following Inco/A treatment, suggesting that its anti-inflammatory effect contributes to nerve regeneration. These findings show that two injections of Inco/A promote functional recovery by enhancing neuroregeneration and modulating inflammatory processes, supporting the hypothesis that Inco/A has a neuroprotective and restorative role in nerve injury conditions. Full article

Spinal cord injury (SCI) is a debilitating condition that results from a culmination of acute and chronic damage to neural tissue, specifically the myelin sheath, thus impacting neurons’ abilities to synergistically perform their physiological roles. This review explores the molecular underpinnings of myelination, demyelination, and remyelination, emphasizing the role of oligodendrocyte progenitor cells (OPCs), astrocytes, and microglia in physiological, and pathophysiological, healing. Furthermore, we link these processes with emerging therapeutic strategies currently under investigation in animal and human models, underscoring areas of translational medicine that remain underutilized. The goal of this review is to provide a framework for developing more advanced interventions to restore function and improve outcomes for individuals with SCI. Full article

This study investigated the changes in protein composition and DNA content in damaged somatic nerves when exposed to insulin-like growth factor-1 (IGF-1). Using electrophoretic protein separation in polyacrylamide gel (PAG) and spectrophotometry, the transection was shown to be accompanied by a significant decrease in the quantitative content of total protein, certain protein fractions and DNA, both in the proximal and distal segments of the nerve conductor. Against the background of the intramuscular administration of IGF-1, intensive DNA synthesis and the protein composition stabilization of somatic nerves at the earlier post-traumatic stages were observed. By means of Raman scattering (RS-spectroscopy) and recording action potentials (APs), the enhanced recovery of the physicochemical condition of the nerve fiber membrane and its functional activity, indicating regeneration activation in the somatic nerves after damage, was revealed. IGF-1 was most likely to stimulate cytoskeleton protein synthesis through launching the mitogen-activated protein kinase signal pathway (MAPK/ERK), resulting in the increased expression of the genes related to the remyelination and functioning recovery of damaged nerve conductors. Full article

Schwann cells (SCs) play a crucial role in peripheral nerve repair by supporting axonal regeneration and remyelination. While extensive research has been conducted using rodent SCs, increasing attention is being directed toward human SCs due to species-specific differences in phenotypical and functional properties, and accessibility of human SCs derived from diverse sources. A major challenge in translating SC-based therapies for nerve repair lies in the inability to replicate human SC myelination in vitro, posing a significant obstacle to drug discovery and preclinical research. In this study, we compared the myelination capacity of human, rodent, and porcine SCs in various co-culture conditions, including species-matched and cross-species neuronal environments in a serum-free medium. Our results confirmed that rodent and porcine SCs readily myelinate neurites under standard culture conditions after treatment with ascorbic acid for two weeks, whereas human SCs, at least within the four-week observation period, failed to show myelin staining in all co-cultures. Furthermore, we investigated whether cell culture manipulation impairs human SC myelination by transplanting freshly harvested and predegenerated human nerve segments into NOD-SCID mice for four weeks. Despite supporting host axonal regeneration into the grafts, human SCs exhibited very limited myelination, suggesting an intrinsic species-specific restriction rather than a cell culture-induced defect. These observations suggest fundamental differences between human and rodent SCs and highlight the need for human-specific models and protocols to advance our understanding of SC myelination. Full article

Traumatic injuries to the peripheral (PNS) and central nervous systems (CNS) trigger distinct regenerative responses, with the PNS displaying limited regenerative capacity and the CNS remaining largely refractory. Recent research highlights the role of epigenetic modifications, particularly histone acetylation, in modulating the gene expression programs that drive axonal regeneration. This review synthesizes current findings on post-translational histone modifications, focusing on histone acetyltransferases (HATs), histone deacetylases (HDACs), and epigenetic readers, in addition to their impact on neuronal and non-neuronal cells following injury. While HATs like p300/CBP and PCAF promote the expression of regeneration-associated genes, HDAC inhibition has been shown to facilitate neurite outgrowth, neuroprotection, and functional recovery in both PNS and CNS models. However, HDAC3, HDAC5, and HDAC6 demonstrate context- and cell-type-specific roles in both promoting and limiting regenerative processes. The review also highlights cell-specific findings that have been scarcely covered in the previous literature. Thus, the immunomodulatory roles of epigenetic regulators in microglia and macrophages, their involvement in remyelination via Schwann cells and oligodendrocytes, and their impact on astrocyte function are within the scope of this review. Closely considering cell-context specificity is critical, as some targets can exert opposite effects depending on the cell type involved. This represents a major challenge for current pharmacological therapies, which often lack precision. This complexity underscores the need to develop strategies that allow for cell-specific delivery or target regulators with converging beneficial effects across cell types. Such approaches may enhance regenerative outcomes after CNS or PNS injury. Full article

Background/Objectives: Demyelination occurs to a variable extent in various neurological diseases, such as multiple sclerosis. Physical exercise benefits central neural functions that depend on the brain’s electrophysiological and glial activity. It is unclear whether both factors—i.e., demyelination and exercise—interact in the brain. We aimed to investigate if this interaction occurs during brain development. Methods: Developing rats were subjected to a cuprizone-induced demyelination. Part of these rats were treadmill-exercised for five weeks. After this period, some demyelinated animals were allowed to remyelinate by receiving a similar diet, without cuprizone, for six weeks. The exercised groups were compared with the corresponding sedentary groups. All groups were evaluated electrophysiologically (cortical spreading depression features), and their brains were processed for immunohistochemical labeling with four specific glial antibodies (anti-APC, MBP, GFAP, and Iba1). Results: Compared with the corresponding controls, cuprizone demyelination and treadmill exercise accelerated and decelerated CSD propagation. Cuprizone reduced APC, MBP, and GFAP immunolabeling and increased Iba1 immunostaining. Remyelination reverted the cuprizone effects. Exercise counteracted the cuprizone-induced changes in GFAP- and Iba1-containing cells but not in MBP- and APC-containing ones. Conclusions: Our data confirmed the effectiveness of the cuprizone demyelination paradigm. They evidenced the potential neuroprotective effect of regular physical exercise, suggesting that this non-pharmacological intervention could benefit patients with central demyelination-dependent diseases. Full article

Adenylyl cyclases (ACs) are key regulators of cyclic adenosine monophosphate (cAMP) signaling—a pathway critical for neuroregeneration, synaptic plasticity, and neuronal survival. In both the central and peripheral nervous systems, injury-induced activation of ACs promotes axonal outgrowth and functional recovery through the stimulation of protein kinase A (PKA), exchange proteins directly activated by cAMP (Epac), and cAMP-response element-binding protein (CREB). Among the various AC isoforms, calcium-sensitive AC1, AC8, and AC5, as well as bicarbonate-responsive soluble AC (sAC), have emerged as crucial mediators of neuroplasticity and axon regeneration. These isoforms coordinate diverse cellular responses—including gene transcription, cytoskeletal remodeling, and neurotransmitter release—to metabolic, synaptic, and injury-related signals. Dysregulation of AC activity has been implicated in the pathophysiology of neurodegenerative diseases such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis, as well as in chronic pain syndromes. Pharmacological modulation of cAMP levels through AC activation, phosphodiesterase (PDE) inhibition, or pituitary adenylyl cyclase-activating polypeptide (PACAP) receptor signaling has shown therapeutic promise in preclinical models by enhancing neurogenesis, remyelination, and synaptic repair. Conversely, targeted inhibition of specific AC isoforms, particularly AC1, has demonstrated efficacy in reducing maladaptive plasticity and neuropathic pain. This review highlights the diverse roles of ACs in neuronal function and injury response and discusses emerging strategies for their therapeutic targeting. Full article

Neurosteroids pregnenolone, progesterone, allopregnanolone, and dehydroepiandrosterone have been actively studied in the last years as candidates for the treatment of neurodegenerative diseases and postinjury rehabilitation. The neuroprotective mechanisms of these neurosteroids have been shown in clinical studies of depression, epilepsy, status epilepticus, traumatic brain injury, fragile X syndrome, and chemical neurotoxicity. However, only the allopregnanolone analogs brexanolone and zuranolone have been recently approved by the FDA for the treatment of depression. The aim of this review was to evaluate whether the endogenous neurosteroids can be used in clinical practice as neuroprotectors. Neurosteroids are multitarget compounds with strong anti-inflammatory, immunomodulatory, and cytoprotective action; they stimulate the synthesis and release of BDNF and increase remyelination and regeneration. In addition to nuclear and membrane steroid hormone receptors, such as PR, mPR, PGRMC1,2, ER, AR, CAR, and PXR, they can bind to GABAA receptors, NMDA receptors, Sigma-1 and -2 receptors (σ1-R/σ2-R). Among these, mPRs, PGRMC1,2, sigma receptors, and mitochondrial proteins attract comprehensive attention because of strong binding with the P4 and DHEA, but subsequent signaling is poorly studied. Other plasma membrane and mitochondrial proteins are involved in the rapid nongenomic neuroprotective action of neurosteroids. P-glycoprotein, BCL-2 proteins, and the components of the mitochondrial permeability transition pore (mPTP) play a significant role in the defense against the injuries of the brain and the peripheral nervous system. The role of these proteins in the molecular mechanisms of action in neuroprotection and neuroinflammation has not yet been clearly established. The aspects of their participation in these pathological processes are discussed. New formulations, such as lipophilic emulsions, nanogels, and microneedle array patches, are attractive strategies to overcome the low bioavailability of these neurosteroids for the amelioration and treatment of various nervous disorders. Full article

Multiple sclerosis (MS) is a multifaceted inflammatory, demyelinating, and neurodegenerative disease typified by lesions with distinct hallmarks in the central nervous system. Dysregulation of micro-environmental factors, including extracellular matrix (ECM) remodelling and glial cell activation, has a decisive effect on lesion development and disease progression. Understanding the biological and pathological features of lesions would aid in prognosis and personalised treatment decision making. Positron emission tomography (PET) is an imaging technique that uses radio-labelled tracers to detect specific biological phenomena. Recent PET hardware developments enable high-resolution, quantitative imaging, which may allow biological characterisation of relatively small MS lesions. PET may complement MRI by offering objective, quantitative insights into lesion characteristics, including myelin density, inflammation and axonal integrity. Moreover, PET may provide information on lesion traits supporting decision making on upcoming therapeutic strategies for progressive MS, such as the availability of oligodendrocyte progenitor cells and ECM composition that affect remyelination and/or axon regeneration. This review explores the cellular and molecular ECM signatures and neuropathological processes of white matter MS lesions, discusses current and potential novel PET targets that may help characterise MS lesions in vivo, and addresses the potential of PET as a decision tool for selection and evaluation of therapeutic strategies, with a focus on remyelination. Full article

The central nervous system (CNS) is highly susceptible to damage due to its limited ability to regenerate. Injuries to the CNS, whether from trauma, ischemia, or neurodegenerative diseases, disrupt both cellular and vascular structures, leading to immediate (primary) and subsequent (secondary) damage. Primary damage involves the physical disruption of cells and blood vessels, weakening the blood–brain barrier (BBB) and triggering excitotoxicity and calcium overload. Secondary damage develops over hours to days and is marked by ionic imbalance, mitochondrial dysfunction, oxidative stress, and chronic inflammation, which further aggravates tissue damage. Inflammation plays a dual role: acute inflammation helps in repair, while chronic inflammation accelerates neurodegeneration. Microglia and astrocytes play key roles in this inflammatory response, with M1-like microglia promoting pro-inflammatory responses and M2-like microglia supporting anti-inflammatory and repair processes. Neurodegenerative diseases are characterized by the accumulation of misfolded proteins such as Tau, amyloid-beta, TDP-43, and α-synuclein, which impair cellular function and lead to neuronal loss. Neurodegenerative diseases are characterized by the accumulation of misfolded proteins and influenced by genetic risk factors (e.g., APOE4, TARDBP). Despite the CNS’s limited regenerative abilities, processes like synaptogenesis, neurogenesis, axonal regeneration, and remyelination offer potential for recovery. Therapeutic approaches aim to target inflammatory pathways, enhance repair mechanisms, and develop neuroprotective treatments to counter excitotoxicity, oxidative stress, and apoptosis. Advances in stem cell therapy, gene therapy, and personalized medicine hold promise for improving outcomes. Future research should focus on combining strategies, utilizing advanced technologies, and conducting translational studies to bridge the gap between preclinical research and clinical application. By better understanding and leveraging the complex processes of CNS injury and repair, researchers hope to develop effective therapies to restore function and enhance the quality of life for individuals with CNS disorders. Full article

Demyelination in the central nervous system (CNS) disrupts neuronal communication and promotes neurodegeneration. Despite the widespread use of cuprizone-induced demyelination models to study myelin injury and repair, the mechanisms underlying oligodendrocyte apoptosis and regeneration are poorly understood. This study investigated the dynamic cellular and molecular changes that occur during demyelination and remyelination, with a focus on glial cell responses, blood-brain barrier (BBB) integrity, and neuroimmune interactions. C57BL/6J mice exposed to cuprizone exhibited weight loss, sensorimotor deficits, and cognitive decline, which were reversed during remyelination. Histological and immunofluorescence analyses revealed reduced myelin protein levels, including myelin basic protein (MBP) and myelin-associated glycoprotein (MAG), and decreased oligodendrocyte populations during demyelination, with recovery during repair. The BBB permeability increases during demyelination, is associated with the decreased expression of tight junction proteins (ZO-1, Occludin), and normalizes during remyelination. Single-cell RNA sequencing revealed dynamic shifts in glial cell populations and upregulated Psap-Gpr37l1 signaling. Neuroimmune activation and oxidative stress peak during demyelination, characterized by elevated ROS, MDA, and immune cell infiltration, followed by recovery. Transcriptomic profiling revealed key inflammatory pathways (JAK-STAT, NF-κB) and hub genes associated with demyelination and repair. These findings provide insights into myelin repair mechanisms and highlight potential therapeutic targets for treating demyelinating diseases. Full article

In the adult central nervous system (CNS), myelin regeneration primarily occurs through the differentiation of oligodendrocyte progenitor cells into mature oligodendrocytes. In men, declining testosterone levels accelerate the progression of multiple sclerosis (MS), while in women, menopause worsens MS-related disability. We previously demonstrated that functional testes and testosterone are required for the spontaneous remyelination of a focal lysolecithin (LPC)-induced demyelinating lesion in the spinal cords of male mice. Testosterone-dependent myelin repair was dependent on the induction of the chemokine receptor CXCR4 in astrocytes that repopulated the lesion and on cooperation between androgen-receptor signaling and CXCR4 signaling. In the present study, we investigated whether ovaries and estradiol have a comparable key role in female mice. Ovariectomy prevents, the appearance of astrocytes, while treatment with estradiol enhances astrocyte numbers and promotes remyelination by oligodendrocytes within the LPC-demyelinated lesion. Unlike testosterone, estradiol did not induce CXCR4 expression, and its effects remained unaffected by the CXCR4 inhibitor AMD3100. As was seen with testosterone treatment, the presence of astrocytes and myelinating oligodendrocytes within the LPC lesion of estradiol-treated females prevented the incursion of Schwann cells. These findings highlight estradiol’s crucial role in CNS remyelination in females, providing a strong rationale for estrogen-replacement therapy in estrogen-deficient and menopausal women with MS. Full article

Neurodegenerative diseases (NDs), including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis/motor neuron disease, and multiple sclerosis, are characterized by progressive loss of neuronal structure and function, leading to severe cognitive, motor, and behavioral impairments. They pose a significant and growing challenge due to their rising prevalence and impact on global health systems. The societal and emotional toll on patients, caregivers, and healthcare infrastructures is considerable. While significant progress has been made in elucidating the pathological hallmarks of these disorders, the underlying cellular and molecular mechanisms remain incompletely understood. Increasing evidence implicates oligodendrocytes and their progenitors—oligodendrocyte progenitor cells (OPCs)—in the pathogenesis of several NDs, beyond their traditionally recognized role in demyelinating conditions such as MS. Oligodendrocytes are essential for axonal myelination, metabolic support, and neural circuit modulation in the central nervous system. Disruptions in oligodendrocyte function and myelin integrity—manifesting as demyelination, hypomyelination, or dysmyelination—have been associated with disease progression in various neurodegenerative contexts. This review consolidates recent findings on the role of OPCs in NDs, explores the concept of myelin plasticity, and discusses therapeutic strategies targeting oligodendrocyte dysfunction. By highlighting emerging research in oligodendrocyte biology, this review aims to provide a short overview of its relevance to neurodegenerative disease progression and potential therapeutic advances. Full article

Peripheral nerve injury disrupts the function of the peripheral nervous system, leading to sensory, motor, and autonomic deficits. While peripheral nerves possess an intrinsic regenerative capacity, complete sensory and motor recovery remains challenging due to the unpredictable nature of the healing process, which is influenced by the extent of the injury, age, and timely intervention. Recent advances in microsurgical techniques, imaging technologies, and a deeper understanding of nerve microanatomy have enhanced functional outcomes in nerve repair. Nerve injury initiates complex pathophysiological responses, including Wallerian degeneration, macrophage activation, Schwann cell dedifferentiation, and axonal sprouting. Complete nerve disruptions require surgical intervention to restore nerve continuity and function. Direct nerve repair is the gold standard for clean transections with minimal nerve gaps. However, in cases with larger nerve gaps or when direct repair is not feasible, alternatives such as autologous nerve grafting, vascularized nerve grafts, nerve conduits, allografts, and nerve transfers may be employed. Autologous nerve grafts provide excellent biocompatibility but are limited by donor site morbidity and availability. Vascularized grafts are used for large nerve gaps and poorly vascularized recipient beds, while nerve conduits serve as a promising solution for smaller gaps. Nerve transfers are utilized when neither direct repair nor grafting is possible, often involving re-routing intact regional nerves to restore function. Nerve conduits play a pivotal role in nerve regeneration by bridging nerve gaps, with significant advancements made in material composition and design. Emerging trends in nerve regeneration include the use of 3D bioprinting for personalized conduits, gene therapy for targeted growth factor delivery, and nanotechnology for nanofiber-based conduits and stem cell therapy. Advancements in molecular sciences have provided critical insights into the cellular and biochemical mechanisms underlying nerve repair, leading to targeted therapies that enhance axonal regeneration, remyelination, and functional recovery in peripheral nerve injuries. This review explores the current strategies for the therapeutic management of peripheral nerve injuries, highlighting their indications, benefits, and limitations, while emphasizing the need for tailored approaches based on injury severity and patient factors. Full article