Neurological diseases are a major health concern, and brain injury is a typical pathological process in various neurological disorders. Different biomarkers in the blood or the cerebrospinal fluid are associated with specific physiological and pathological processes. They are vital in identifying, diagnosing, and treating brain injuries. In this review, we described biomarkers for neuronal cell body injury (neuron-specific enolase, ubiquitin C-terminal hydrolase-L1, αII-spectrin), axonal injury (neurofilament proteins, tau), astrocyte injury (S100β, glial fibrillary acidic protein), demyelination (myelin basic protein), autoantibodies, and other emerging biomarkers (extracellular vesicles, microRNAs). We aimed to summarize the applications of these biomarkers and their related interests and limits in the diagnosis and prognosis for neurological diseases, including traumatic brain injury, status epilepticus, stroke, Alzheimer's disease, and infection. In addition, a reasonable outlook for brain injury biomarkers as ideal detection tools for neurological diseases is presented.
Humans ; Biomarkers/cerebrospinal fluid* ; Nervous System Diseases/diagnosis* ; Brain Injuries/metabolism* ; Phosphopyruvate Hydratase/cerebrospinal fluid* ; Glial Fibrillary Acidic Protein/blood* ; S100 Calcium Binding Protein beta Subunit/blood* ; tau Proteins/cerebrospinal fluid* ; Ubiquitin Thiolesterase/blood* ; Myelin Basic Protein/cerebrospinal fluid* ; Neurofilament Proteins/blood* ; MicroRNAs/blood* ; Brain Injuries, Traumatic/metabolism*

Oligodendrocyte lineage cells, including oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs), are essential in establishing and maintaining brain circuits. Autophagy is a conserved process that keeps the quality of organelles and proteostasis. The role of autophagy in oligodendrocyte lineage cells remains unclear. The present study shows that autophagy is required to maintain the number of OPCs/OLs and myelin integrity during brain aging. Inactivation of autophagy in oligodendrocyte lineage cells increases the number of OPCs/OLs in the developing brain while exaggerating the loss of OPCs/OLs with brain aging. Inactivation of autophagy in oligodendrocyte lineage cells impairs the turnover of myelin basic protein (MBP). It causes MBP to accumulate in the cytoplasm as multimeric aggregates and fails to be incorporated into integral myelin, which is associated with attenuated endocytic recycling. Inactivation of autophagy in oligodendrocyte lineage cells impairs myelin integrity and causes demyelination. Thus, this study shows autophagy is required to maintain myelin quality during aging by controlling the turnover of myelin components.
Animals ; Autophagy/physiology* ; Oligodendroglia/metabolism* ; Myelin Sheath/physiology* ; Aging/pathology* ; Myelin Basic Protein/metabolism* ; Cell Lineage/physiology* ; Mice ; Oligodendrocyte Precursor Cells ; Mice, Inbred C57BL ; Brain/cytology* ; Cells, Cultured ; Cell Count

The obstacle to successful remyelination in demyelinating diseases, such as multiple sclerosis, mainly lies in the inability of oligodendrocyte precursor cells (OPCs) to differentiate, since OPCs and oligodendrocyte-lineage cells that are unable to fully differentiate are found in the areas of demyelination. Thus, promoting the differentiation of OPCs is vital for the treatment of demyelinating diseases. Shikimic acid (SA) is mainly derived from star anise, and is reported to have anti-influenza, anti-oxidation, and anti-tumor effects. In the present study, we found that SA significantly promoted the differentiation of cultured rat OPCs without affecting their proliferation and apoptosis. In mice, SA exerted therapeutic effects on experimental autoimmune encephalomyelitis (EAE), such as alleviating clinical EAE scores, inhibiting inflammation, and reducing demyelination in the CNS. SA also promoted the differentiation of OPCs as well as their remyelination after lysolecithin-induced demyelination. Furthermore, we showed that the promotion effect of SA on OPC differentiation was associated with the up-regulation of phosphorylated mTOR. Taken together, our results demonstrated that SA could act as a potential drug candidate for the treatment of demyelinating diseases.
Animals ; Apoptosis ; drug effects ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Demyelinating Diseases ; prevention & control ; Encephalitis ; prevention & control ; Encephalomyelitis, Autoimmune, Experimental ; prevention & control ; Female ; Mice, Inbred C57BL ; Myelin Basic Protein ; metabolism ; Neuroprotective Agents ; administration & dosage ; Oligodendrocyte Precursor Cells ; drug effects ; metabolism ; Rats ; Remyelination ; drug effects ; Shikimic Acid ; administration & dosage ; TOR Serine-Threonine Kinases ; metabolism

Oligodendrocytes (OLs) are myelinating glial cells that form myelin sheaths around axons to ensure rapid and focal conduction of action potentials. Here, we found that an axonal outgrowth regulatory molecule, AATYK (apoptosis-associated tyrosine kinase), was up-regulated with OL differentiation and remyelination. We therefore studied its role in OL differentiation. The results showed that AATYK knockdown inhibited OL differentiation and the expression of myelin genes in vitro. Moreover, AATYK-deficiency maintained the proliferation status of OLs but did not affect their survival. Thus, AATYK is essential for the differentiation of OLs.
Animals ; Animals, Newborn ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Cell Differentiation ; drug effects ; physiology ; Cell Proliferation ; drug effects ; genetics ; Cells, Cultured ; Cuprizone ; toxicity ; Demyelinating Diseases ; chemically induced ; metabolism ; pathology ; Embryo, Mammalian ; Gene Expression Regulation, Developmental ; genetics ; Ki-67 Antigen ; metabolism ; Mice ; Mice, Inbred C57BL ; Myelin Basic Protein ; metabolism ; Myelin Proteolipid Protein ; metabolism ; Myelin Sheath ; drug effects ; metabolism ; Oligodendroglia ; drug effects ; metabolism ; Protein-Tyrosine Kinases ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

We investigated the potential of human dental pulp stem cells (hDPSCs) to differentiate into dopaminergic neurons in vitro as an autologous stem cell source for Parkinson's disease treatment. The hDPSCs were expanded in knockout-embryonic stem cell (KO-ES) medium containing leukemia inhibitory factor (LIF) on gelatin-coated plates for 3-4 days. Then, the medium was replaced with KO-ES medium without LIF to allow the formation of the neurosphere for 4 days. The neurosphere was transferred into ITS medium, containing ITS (human insulin-transferrin-sodium) and fibronectin, to select for Nestin-positive cells for 6-8 days. The cells were then cultured in N-2 medium containing basic fibroblast growth factor (FGF), FGF-8b, sonic hedgehog-N, and ascorbic acid on poly-l-ornithine/fibronectin-coated plates to expand the Nestin-positive cells for up to 2 weeks. Finally, the cells were transferred into N-2/ascorbic acid medium to allow for their differentiation into dopaminergic neurons for 10-15 days. The differentiation stages were confirmed by morphological, immunocytochemical, flow cytometric, real-time PCR, and ELISA analyses. The expressions of mesenchymal stem cell markers were observed at the early stages. The expressions of early neuronal markers were maintained throughout the differentiation stages. The mature neural markers showed increased expression from stage 3 onwards. The percentage of cells positive for tyrosine hydroxylase was 14.49%, and the amount was 0.526 ± 0.033 ng/mL at the last stage. hDPSCs can differentiate into dopaminergic neural cells under experimental cell differentiation conditions, showing potential as an autologous cell source for the treatment of Parkinson's disease.
Animals ; Brain/pathology ; *Cell Differentiation/drug effects ; Cells, Cultured ; Culture Media/chemistry/pharmacology ; Dental Pulp/*cytology ; Dopaminergic Neurons/*cytology/*metabolism/pathology ; Enzyme-Linked Immunosorbent Assay ; Glial Fibrillary Acidic Protein/genetics/metabolism ; Humans ; Mice ; Mice, Inbred ICR ; Myelin Basic Protein/genetics/metabolism ; Real-Time Polymerase Chain Reaction ; Stage-Specific Embryonic Antigens/genetics/metabolism ; Stem Cells/*cytology/*metabolism/pathology ; Tubulin/genetics/metabolism ; Tyrosine 3-Monooxygenase/analysis/genetics/metabolism

We investigated the potential of human dental pulp stem cells (hDPSCs) to differentiate into dopaminergic neurons in vitro as an autologous stem cell source for Parkinson's disease treatment. The hDPSCs were expanded in knockout-embryonic stem cell (KO-ES) medium containing leukemia inhibitory factor (LIF) on gelatin-coated plates for 3-4 days. Then, the medium was replaced with KO-ES medium without LIF to allow the formation of the neurosphere for 4 days. The neurosphere was transferred into ITS medium, containing ITS (human insulin-transferrin-sodium) and fibronectin, to select for Nestin-positive cells for 6-8 days. The cells were then cultured in N-2 medium containing basic fibroblast growth factor (FGF), FGF-8b, sonic hedgehog-N, and ascorbic acid on poly-l-ornithine/fibronectin-coated plates to expand the Nestin-positive cells for up to 2 weeks. Finally, the cells were transferred into N-2/ascorbic acid medium to allow for their differentiation into dopaminergic neurons for 10-15 days. The differentiation stages were confirmed by morphological, immunocytochemical, flow cytometric, real-time PCR, and ELISA analyses. The expressions of mesenchymal stem cell markers were observed at the early stages. The expressions of early neuronal markers were maintained throughout the differentiation stages. The mature neural markers showed increased expression from stage 3 onwards. The percentage of cells positive for tyrosine hydroxylase was 14.49%, and the amount was 0.526 ± 0.033 ng/mL at the last stage. hDPSCs can differentiate into dopaminergic neural cells under experimental cell differentiation conditions, showing potential as an autologous cell source for the treatment of Parkinson's disease.
Animals ; Brain/pathology ; *Cell Differentiation/drug effects ; Cells, Cultured ; Culture Media/chemistry/pharmacology ; Dental Pulp/*cytology ; Dopaminergic Neurons/*cytology/*metabolism/pathology ; Enzyme-Linked Immunosorbent Assay ; Glial Fibrillary Acidic Protein/genetics/metabolism ; Humans ; Mice ; Mice, Inbred ICR ; Myelin Basic Protein/genetics/metabolism ; Real-Time Polymerase Chain Reaction ; Stage-Specific Embryonic Antigens/genetics/metabolism ; Stem Cells/*cytology/*metabolism/pathology ; Tubulin/genetics/metabolism ; Tyrosine 3-Monooxygenase/analysis/genetics/metabolism

Emerging evidence indicates that microglia activation plays an important role in spinal cord injury (SCI) caused by trauma. Studies have found that inhibiting the Rho/Rho-associated protein kinase (ROCK) signaling pathway can reduce inflammatory cytokine production by microglia. In this study, Western blotting was conducted to detect ROCK2 expression after the SCI; the ROCK Activity Assay kit was used for assay of ROCK pathway activity; microglia morphology was examined using the CD11b antibody; electron microscopy was used to detect microglia phagocytosis; TUNEL was used to detect tissue cell apoptosis; myelin staining was performed using an antibody against myelin basic protein (MBP); behavioral outcomes were evaluated according to the methods of Basso, Beattie, and Bresnahan (BBB). We observed an increase in ROCK activity and microglial activation after SCI. The microglia became larger and rounder and contained myelin-like substances. Furthermore, treatment with fasudil inhibited neuronal cells apoptosis, alleviated demyelination and the formation of cavities, and improved motor recovery. The experimental evidence reveals that the ROCK inhibitor fasudil can regulate microglial activation, promote cell phagocytosis, and improve the SCI microenvironment to promote SCI repair. Thus, fasudil may be useful for the treatment of SCI.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine ; analogs & derivatives ; pharmacology ; therapeutic use ; Animals ; Apoptosis ; Male ; Microglia ; drug effects ; metabolism ; Myelin Basic Protein ; metabolism ; Myelin Sheath ; metabolism ; Phagocytosis ; Protein Kinase Inhibitors ; pharmacology ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Spinal Cord Injuries ; drug therapy ; rho-Associated Kinases ; antagonists & inhibitors ; metabolism

OBJECTIVETo study the effects of caffeine citrate on myelin basic protein (MBP) expression in the cerebral white matter of neonatal rats with hypoxic-ischemic brain damage (HIBD) and the related mechanism.

METHODSForty-eight seven-day-old Sprague-Dawley neonatal rats were randomly assigned to 3 groups: sham operation (n=16), HIBD (n=16) and HIBD+caffeine citrate (n=16). The rats in the HIBD and HIBD+caffeine citrate groups were subjected to left common carotid artery ligation, and then were exposed to 80 mL/L oxygen and 920 mL/L nitrogen for 2 hours to induce HIBD. The rats in the sham operation group were only subjected to a sham operation, without the left common carotid artery ligation or hypoxia exposure. Caffeine citrate (20 mg/kg) was injected intraperitoneally before hypoxia ischemia (HI) and immediately, 24 hours, 48 hours and 72 hours after HI. The other two groups were injected intraperitoneally with an equal volume of normal saline at the corresponding time points. On postnatal day 12, the expression of MBP in the left subcortical white matter was detected by immunohistochemistry, and the levels of adenosine A1 receptor mRNA and A2a receptor mRNA in the left brain were detected by real-time PCR.

RESULTSThe expression of MBP in the left subcortical white matter in the HIBD group was lower than in the sham operation group (P<0.05). The MBP expression in the HIBD+caffeine citrate group was significantly higher than in the HIBD group, but was still lower than the sham operation group (P<0.05). Real-time PCR showed that the adenosine A1 receptor mRNA expression was significantly higher in the HIBD group than in the sham operation group, and it was significantly lower in the HIBD+caffeine citrate group than in the HIBD group (P<0.05).

CONCLUSIONSCaffeine citrate can improve brain white matter damage following HIBD in neonatal rats and the protection mechanism might be related with the down-regulation of adenosine A1 receptor expression.

Animals ; Animals, Newborn ; Caffeine ; pharmacology ; Citrates ; pharmacology ; Female ; Hypoxia-Ischemia, Brain ; drug therapy ; metabolism ; pathology ; Male ; Myelin Basic Protein ; analysis ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Receptor, Adenosine A1 ; genetics ; Receptor, Adenosine A2A ; genetics ; White Matter ; chemistry

OBJECTIVETo study the role and effect of Schwann cells (SCs) remyelination in contused spinal cord.

METHODSGreen fluorescence protein expressing-SCs were transplanted into the epicenter, rostral and caudal tissues of the injury site at 1 week after the spinal cords were contused. At 6 weeks, the spinal cords were removed for cryosections, semithin sections and ultrathin sections, and then immunocytochemical staining of myelin basic protein (MBP), P0 protein (P0) and S100 protein (S100) was carried out on the cryosections. Qualitative and semiquantitative analyses were performed on the cryosections and semithin sections. Ultrastructure of myelinated fibers was observed on the ultrathin sections under electron microscope.

RESULTSTransplanted SCs and myelinated fibers immunocytochemically labeled by MBP, P0 as well as S100 distributed in whole injured area. The quantity of myelinated fibers labeled by the three myelin proteins showed no statistical difference, however, which was significantly larger than that of controls. On the semithin sections, the experimental group demonstrated more myelinated fibers in the injured area than the controls, but the fibers had smaller diameter and thinner myelin sheath under electron microscope.

CONCLUSIONSCs can promote regeneration of injured nerve fibers and enhance remyelination, which may be histological basis of SCs-mediated functional repair of injured spinal cords.

Animals ; Immunohistochemistry ; Microscopy, Electron ; Myelin Basic Protein ; metabolism ; Myelin P0 Protein ; metabolism ; Nerve Regeneration ; physiology ; Rats ; Rats, Sprague-Dawley ; S100 Proteins ; metabolism ; Schwann Cells ; physiology ; ultrastructure ; Spinal Cord Injuries ; metabolism ; physiopathology

Acclimatization ; physiology ; Adult ; Altitude ; Fatty Acid-Binding Proteins ; metabolism ; Humans ; Male ; Middle Aged ; Myelin Basic Protein ; metabolism ; Nervous System Diseases ; metabolism ; Occupational Exposure ; Succinate Dehydrogenase ; metabolism