Effect of CSF1R inhibitor on glial cells population and remyelination in the cuprizone model.

Multiple sclerosis is a kind of autoimmune and demyelinating disease with pathological symptoms such as inflammation, myelin loss, astrocytosis, and microgliosis. The colony stimulating factor 1 receptor (CSF1R) is an essential factor for the microglial function, and PLX3397 (PLX) is its specific inhibitor. In this wstudy, we assessed the effect of different doses of PLX for microglial ablation on glial cell population and remyelination process. Sixty male C57BL/6 mice (8 weeks old) were divided into 6 groups. The animals were fed with 0.2% cuprizone diet for 12 weeks. For microglial ablation, PLX (290 mg/kg) was added to the animal food for 3, 7, 14 and 21 days. Glial cell population was measured using immunohistochemistry. The rate of remyelination was evaluated using electron microscopy and Luxol Fast Blue staining. The expression levels of all genes were assessed by qRT-PCR method. Data were analysed using GraphPad Prism and SPSS software. The results showed that the administration of different doses of PLX significantly reduced microglial cells (p ≤ .001). PLX administration also significantly increased oligodendrocytes population (p ≤ .001) and remyelination compared to the cuprizone mice, which was aligned with the results of LFB and TEM. Gene results showed that PLX treatment reduced CSF1R expression. According to the results, the administration of PLX for 21 days enhanced remyelination by increasing oligodendrocytes in the chronic demyelination model. These positive effects could be related to the reduction of microglia.

Tahmasebi F ，Barati S ，Kashani IR 《-》

The effect of microglial ablation and mesenchymal stem cell transplantation on a cuprizone-induced demyelination model.

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the central nervous system with symptoms such as neuroinflammation, astrocytosis, microgliosis, and axonal degeneration. Mesenchymal stem cells (MSCs) with their immunomodulation, differentiation, and neuroprotection abilities can influence the remyelination process. The goal of this study is to investigate the impact of microglial ablation and MSCs transplantation on remyelination processes in the corpus callosum (CC) of the cuprizone demyelination model. For the induction of a chronic demyelination model, C57BL6 mice were fed with chow containing 0.2% cuprizone (wt/wt) for 12 weeks. For the depletion of microglia, PLX3397 was used as a colony-stimulating factor 1 receptor inhibitor for 21 days. MSCs were injected to the right lateral ventricle and after 2 weeks, the mice were killed. We assessed glial cells using specific markers such as APC, Iba-1, and GFAP using the immunohistochemistry method. Remyelination was evaluated by Luxol fast blue (LFB) staining and transmission electron microscope (TEM). The specific genes of microglia and MSCs were evaluated by a quantitative real-time polymerase chain reaction. According to the results of the study, 21 days of PLX3397 treatment significantly reduced microglial cells, and MSCs transplantation decreased the number of astrocytes, whereas the oligodendrocytes population increased significantly in PLX + MSC group in comparison with the cuprizone mice. Furthermore, PLX and MSC treatment elevated levels of remyelination compared with the cuprizone group, as confirmed by LFB staining and TEM analysis. The molecular results showed that MSC transplantation significantly decreased the number of microglia through the CX3CL1/CX3CR1 axis. These results revealed that PLX3397 treatment and MSCs injection reduced microgliosis and astrocytosis. It also increased the oligodendrocytes population by enhancing remyelination in the CC of the cuprizone model of MS.

Tahmasebi F ，Pasbakhsh P ，Barati S ，Madadi S ，Kashani IR ... -  《-》

Effect of the CSF1R inhibitor PLX3397 on remyelination of corpus callosum in a cuprizone-induced demyelination mouse model.

Multiple sclerosis (MS) is a chronic inflammatory disease affecting the central nervous system (CNS). Despite introducing multiple immunomodulatory approaches for MS, there are still major concerns about possible ways for improving remyelination in this disease. Microglia exert essential roles in regulation of myelination processes, and interaction between colony-stimulating factor 1 (CSF1) with its receptor CSF1R is considered as a key regulator of microglial differentiation and survival. The aim of this study was to investigate possible roles for a CSF1R inhibitor PLX3397 in recovery of central myelination processes. Chronic demyelination was induced in mice by addition of 0.2% cuprizone to the chow for 12 weeks. Next, animals were undergoing a diet containing 290 mg/kg PLX3397 to induce microglial ablation. The PLX3397 treatment caused a significant decrease in the rate of expression for the CSF1/CSF1R axis, and a reduction in the protein expressions for the microglial marker Iba-1 and for the oligodendrocyte marker Olig-2. Findings from Luxol fast blue (LFB) staining and transmission electron microscopy (TEM) showed an increase in the rate of myelination for the mice receiving PLX3397. The rate of destruction in the nerve fibers and the extent of the gaps formed between layers of myelin sheaths was also reduced after the treatment with PLX3397. In addition, animals experienced an improvement in recovery of motor deficit after receiving PLX3397 (for all P < 0.05). It could be concluded that PLX3397 could retain myelination in the MS model possibly through regulation of the myelin environment.

Tahmasebi F ，Pasbakhsh P ，Mortezaee K ，Madadi S ，Barati S ，Kashani IR ... -  《-》

Astrocyte ablation induced by La-aminoadipate (L-AAA) potentiates remyelination in a cuprizone demyelinating mouse model.

Madadi S ，Pasbakhsh P ，Tahmasebi F ，Mortezaee K ，Khanehzad M ，Boroujeni FB ，Noorzehi G ，Kashani IR ... -  《-》

Coenzyme Q10 enhances remyelination and regulate inflammation effects of cuprizone in corpus callosum of chronic model of multiple sclerosis.

Khalilian B ，Madadi S ，Fattahi N ，Abouhamzeh B ... -  《-》