Claudin-1 and Claudin-3 as Molecular Regulators of Myelination in Leukoaraiosis Patients.

OBJECTIVES: Leukoaraiosis is described as white matter lesions that are associated with cognitive dysfunction, neurodegenerative disorders, etc. Myelin depletion is a salient pathological feature of, and the loss of oligodendrocytes is one of the most robust alterations evident in, white matter degeneration. Recent studies have revealed that claudin proteins are aberrantly expressed in leukoaraiosis and regulate oligodendrocyte activity. However, the roles of claudin-1 and claudin-3 in oligodendrocytes and leukoaraiosis are still not well-defined. METHODS: Quantitative polymerase chain reaction was used to measure the expression of claudin-1 (CLDN1), claudin-3 (CLDN3), and myelinogenesis-related genes such as myelin basic protein (MBP), proteolipid protein (PLP), oligodendrocyte transcription factor 2 (OLIG2), and SRY-box transcription factor 10 (SOX10) in leukoaraiosis patients (n=122) and healthy controls (n=122). The expression of claudin-1 and claudin-3 was either ectopically silenced or augmented in Oli-neu oligodendrocytes, and colony formation, apoptosis, and migration assays were performed. Finally, the expression of myelin proteins was evaluated by western blotting. RESULTS: Our results revealed that in addition to SOX10, the expression levels of claudin-1, claudin-3, and myelinogenesis-related proteins were prominently downregulated in leukoaraiosis patients, compared to those in healthy controls. Furthermore, the growth and migration of Oli-neu cells were downregulated upon silencing claudin-1 or claudin-3. However, the overexpression of claudin-1 or claudin-3 resulted in the reduction of the degree of apoptosis in Oli-neu cells. In addition, claudin-1 and claudin-3 promoted the expression of MBP, OLIG2, PLP, and SOX10 at the translational level. CONCLUSION: Our data has demonstrated that the abnormal expression of claudin-1 and claudin-3 regulates the pathological progression of leukoaraiosis by governing the viability and myelination of oligodendrocytes. These findings provide novel insights into the regulatory mechanisms underlying the roles of claudin-1 and claudin-3 in leukoaraiosis.

[Clinical characteristics and genetic analysis of a Chinese pedigree affected with thiamine pyrophosphokinase deficiency].

OBJECTIVE: To investigate the clinical characteristics and genetic variant in a Chinese pedigree affected with thiamine pyrophosphokinase deficiency (TPKD). METHODS: Clinical data of the pedigree were analyzed retrospectively and summarized from the perspectives of clinical manifestation, magnetic resonance imaging (MRI), and genotype. Relevant literature was also reviewed. RESULTS: The proband, a female, has developed paroxysmal ataxia with dystonia at the age of 2-year-and-8-month. The ataxia has recurred for 7-8 times. The child had died at 11 years old due to recurrence and aggravation of the disease. MRI showed diffuse symmetrical lesions of brain parenchyma and spinal cord. Her brother had similar symptoms and died at 6. The parents were consanguineous but healthy. Genetic testing revealed that the girl has carried homozygous c.161C>T variants of the TPK1 gene, suggesting the diagnosis of TPKD. So far 15 cases of TPKD have been reported, among which 9 were from consanguineous marriages. The disease usually occurs before the age of 3, and most patients had featured paroxysmal encephalopathy and recurrent infections. Symmetrical celebral cortex, basal ganglia and cerebellum lesions were common. Missense mutations of the TPK1 gene were common. Vitamin B1 was effective in some cases. CONCLUSION: For infants featuring encephalopathy, ataxia, dystonia and other phenotypes, early genetic testing should be recommended in order to provide guidance for clinical treatment and genetic counseling.

Claudin-1 and Claudin-3 as Molecular Regulators of Myelination in Leukoaraiosis Patients

OBJECTIVES: Leukoaraiosis is described as white matter lesions that are associated with cognitive dysfunction, neurodegenerative disorders, etc. Myelin depletion is a salient pathological feature of, and the loss of oligodendrocytes is one of the most robust alterations evident in, white matter degeneration. Recent studies have revealed that claudin proteins are aberrantly expressed in leukoaraiosis and regulate oligodendrocyte activity. However, the roles of claudin-1 and claudin-3 in oligodendrocytes and leukoaraiosis are still not well-defined. METHODS: Quantitative polymerase chain reaction was used to measure the expression of claudin-1 (CLDN1), claudin-3 (CLDN3), and myelinogenesis-related genes such as myelin basic protein (MBP), proteolipid protein (PLP), oligodendrocyte transcription factor 2 (OLIG2), and SRY-box transcription factor 10 (SOX10) in leukoaraiosis patients (n=122) and healthy controls (n=122). The expression of claudin-1 and claudin-3 was either ectopically silenced or augmented in Oli-neu oligodendrocytes, and colony formation, apoptosis, and migration assays were performed. Finally, the expression of myelin proteins was evaluated by western blotting. RESULTS: Our results revealed that in addition to SOX10, the expression levels of claudin-1, claudin-3, and myelinogenesis-related proteins were prominently downregulated in leukoaraiosis patients, compared to those in healthy controls. Furthermore, the growth and migration of Oli-neu cells were downregulated upon silencing claudin-1 or claudin-3. However, the overexpression of claudin-1 or claudin-3 resulted in the reduction of the degree of apoptosis in Oli-neu cells. In addition, claudin-1 and claudin-3 promoted the expression of MBP, OLIG2, PLP, and SOX10 at the translational level. CONCLUSION: Our data has demonstrated that the abnormal expression of claudin-1 and claudin-3 regulates the pathological progression of leukoaraiosis by governing the viability and myelination of oligodendrocytes. These findings provide novel insights into the regulatory mechanisms underlying the roles of claudin-1 and claudin-3 in leukoaraiosis.

[Transplanted adipose-derived stem cells promote the expression of deleted in colorectal cancer (DCC) and neurofilament-200 (NF-200) in peri-infarct cortex of rats].

Objective To investigate the effects of adipose-derived stem cells (ADSCs) transplantation on the expression of deleted in colorectal cancer (DCC) and neurofilament-200 (NF-200) in peri-infarct cortex of rats. Methods SD rats were randomly divided into sham group, model group and ADSCs group. The rat model of middle cerebral artery occlusion (MCAO) was established with the modified Longa's method. Twenty-four hours after MCAO, 50 µL of cell suspension containing about 2×106 PKH-26-labeled ADSCs was injected into the carotid artery of rats in the ADSCs group, and the same dose of saline was given to the rats in the model group. Day 7 and 14 after MCAO, the migration of ADSCs in rat brains was observed under a fluorescence microscope, and the protein levels of DCC and NF-200 in the peri-infarct cortex were measured by Western blot analysis and the expression and distribution of DCC and NF-200 were detected by immunofluorescent histochemistry. Results PKH-26-labeled ADSCs were observed in the rat brains of ADSC group, and most of them were located in the peri-infarct cortex. At 7 and 14 days after MCAO, the expression of DCC in the model group was higher than that in the sham group, while the expression level of NF-200 was lower. Besides, the expression of DCC and NF-200 in the ADSC group was both higher than that in the model group. In the peri-infract cortex, DCC was mainly expressed in NF-200-positive neuronal axons. Conclusion The ADSCs can migrate to the peri-infarct cortex after transplantation via carotid artery, and may strengthen the axonal regeneration and repairment by promoting the expression of DCC and NF-200 in this region.

Effects of intra-arterial transplantation of adipose-derived stem cells on the expression of netrin-1 and its receptor DCC in the peri-infarct cortex after experimental stroke.

BACKGROUND: Stem cell transplantation has been documented to promote functional recovery in animal models of stroke; however, the underlying mechanisms are not yet fully understood. As netrin-1 and its receptor deleted in colorectal cancer (DCC) are important regulators in neuronal and vascular activities, the present study attempted to explore whether netrin-1 and DCC are involved in the neuroprotection of stem cell-based therapies in a rat ischemic stroke model. METHODS: Adult male Sprague-Dawley rats were subjected to a transient middle cerebral artery occlusion (MCAO) and subsequently received an intra-arterial injection of 2 × 106 PKH26-labeled adipose-derived stem cells (ADSCs) or saline 24 h later. Neurological function was evaluated by behavioral tests before the rats were sacrificed at days 7 and 14 after MCAO. The migration of ADSCs and regeneration of neuronal fibers and blood vessels were determined by immunofluorescence staining. The expression of netrin-1 and DCC was analyzed by Western blot and immunofluorescence staining. RESULTS: ADSC transplantation significantly improved the neurological recovery at days 7 and 14, and noticeably promoted the regeneration of neuronal fibers and blood vessels in the peri-infarct cortex at day 14. PKH26-labeled ADSCs located mainly in the peri-infarct area at days 7 and 14. In ADSC-treated rats, the expression of netrin-1 and DCC significantly increased in the peri-infarct cortex at days 7 and 14. Immunofluorescence staining showed that netrin-1 was mainly expressed by neuronal perikaryal in the peri-infarct cortex, and DCC was mainly expressed by neuronal fibers and was present around the blood vessels in the peri-infarct cortex. CONCLUSIONS: These findings suggest that ADSC transplantation facilitates the regeneration of neuronal fibers and blood vessels in the peri-infarct cortex and improves neurological functions, which may be attributed, at least in part, to the involvement of upregulated netrin-1 and DCC in the remodeling of neuronal and vascular networks in the peri-infarct cortex.