Most cerebellar ataxias (cAs) are incurable neurological disorders, resulting in a lack of voluntary control by inflamed or damaged cerebellum. Although CA can be either directly or indirectly related to cerebellar inflammation, there is no suitable animal model of CA with neuroinflammation. In this study, we evaluated the utility of an intracerebellar injection of lipopolysaccharide (LpS) to generate an animal model of inflammatory CA. We observed that LPS administration induced the expression of pro-inflammatory molecules following activation of glial cells. In addition, the administration of LPS resulted in apoptotic purkinje cell death and induced abnormal locomotor activities, such as impaired motor coordination and abnormal hindlimb clasping posture. Our results suggest that intracerebellar LPS administration in experimental animals may be useful for studying the inflammatory component of CA. Cerebellar ataxias (CAs) are motor neuron diseases caused by pathological processes affecting the cerebellum or its associated pathways 1,2. They are characterised by symptoms such as abnormal coordination of balance, movement and gait. Currently, most CAs are incurable, with few exceptions, and only symptom alleviation is possible 3. CAs can be caused by genetic defects, sporadic neurodegenerative disorders, and acquired conditions (for example, infections, toxic reactions, alcohol, and vitamin deficiencies), but they can also arise for unknown reasons 1,3,4. In particular, many reports have shown a close relationship between cerebellar inflammation and CA 1,3,5. The activation of glial cells resulting in the production of pro-inflammatory molecules has been observed in many animal models of CA and is also evident in the cerebellums of patients with CA 6-9. Furthermore, cerebellar inflammation has been shown to induce the loss of Purkinje cells, which results in cerebellar dysfunction 1,7. Although the understanding of CA pathogenesis associated with genetic causes, cerebellar neurotoxicity, and physical damage has contributed to the development of some animal models of CA 1,3 , there is no suitable animal model to study CA following glial activation and neurotoxic cerebellar inflammation in vivo. Neuroinflammation plays a crucial role in the pathogenesis and progression of neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease 10. As a potent stimulator of neuroinflammation, lipopolysaccharide (LPS) has been used to mediate neurodegenerative progression 11. An accumulation of evidence has shown that LPS-induced neuroinflammation causes neuronal damage through activation of microglia and astrocytes, M1 microglial polarization and the release of pro-inflammatory mediators. For example, LPS injected into the substantia nigra induces microglia activation, which causes the degeneration of dopamine neurons that constitutes the pathological basis of Parkinson's disease 12. In addition, LPS causes an increase in amyloid beta, which results in demyelination and oligodendrocyte injury in mice brains, w...

Mesenchymal stem cell (MSC) therapy is a promising alternative approach for the treatment of neurodegenerative diseases, according to its neuroprotective and immunomodulatory potential. Despite numerous clinical trials involving autologous MSCs, their outcomes have often been unsuccessful. Several reports have indicated that MSCs from patients have low capacities in terms of the secretion of neurotrophic or anti-inflammatory factors, which might be associated with cell senescence or disease severity. Therefore, a new strategy to improve their capacities is required for optimal efficacy of autologous MSC therapy. In this study, we compared the secretory potential of MSCs among cerebellar ataxia patients (CA-MSCs) and healthy individuals (H-MSCs). Our results, including secretome analysis findings, revealed that CA-MSCs have lower capacities in terms of proliferation, oxidative stress response, motility, and immunomodulatory functions when compared with H-MSCs. The functional differences were validated in a scratch wound healing assay and neuron-glia co-cultures. In addition, the neuroprotective and immunoregulatory protein follistatin-like 1 (FSTL1) was identified as one of the downregulated proteins in the CA-MSC secretome, with suppressive effects on proinflammatory microglial activation. Our study findings suggest that targeting aspects of the downregulated anti-inflammatory secretome, such as FSTL1, might improve the efficacy of autologous MSC therapy for CA.

We recently reported that upregulation of the constitutively active ras homolog enriched in brain [Rheb(S16H)], which induces the activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, can protect adult neurons, mediated by the induction of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF), in animal models of neurodegenerative diseases. Here we show that neuronal transduction of Rheb(S16H) using adeno-associated virus serotype 1 provides neuroprotection in a mouse model of photothrombosis-induced ischemic stroke. Rheb(S16H)-expressing neurons exhibited neurotrophic effects, such as mTORC1 activation, increases in neuronal size, and BDNF production, in mouse cerebral cortex. Moreover, the upregulation of neuronal Rheb(S16H) significantly attenuated ischemic damage and behavioral impairments as compared to untreated mice, suggesting that Rheb(S16H) upregulation in cortical neurons may be a useful strategy to treat ischemic stroke.

Cerebellar ataxias (CAs) are neurological diseases characterized by loss of muscle coordination that is a result of damage and inflammation to the cerebellum. Despite considerable efforts in basic and clinical research, most CAs are currently incurable. In this study, we evaluated the therapeutic potential of human mesenchymal stem cells (hMSCs) against CAs associated with neuroinflammation. We observed that hMSC treatment significantly inhibited the symptoms of ataxia in lipopolysaccharide (LPS)-induced inflammatory CA (ICA) mice, which were recently reported as a potential animal model of ICA, through the anti-inflammatory effect of hMSC-derived TNFα-stimulated gene-6 (TSG-6), the protection of Purkinje cells by inhibition of apoptosis, and the modulatory effect for microglial M2 polarization. Thus, our results suggest that hMSC treatment may be an effective therapeutic approach for preventing or improving ataxia symptoms.

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