Mechanism of M2 macrophages modulating astrocyte polarization through the TGF-ß/PI3K/Akt pathway.

Recent studies have revealed that activated astrocytes (AS) are divided into two distinct types, termed A1 and A2. A2 astrocytes are neuroprotective and promote tissue repair and regeneration following spinal cord injury. Whereas, the specific mechanism for the formation of the A2 phenotype remains unclear. This study focused on the PI3K/Akt pathway and examined whether TGF-ß secreted by M2 macrophages could mediate A2 polarization by activating this pathway. In this study, we revealed that both M2 macrophages and their conditioned medium (M2-CM) could facilitate the secretion of IL-10, IL-13 and TGF-ß from AS, and this effect was significantly reversed after the administration of SB431542 (a TGF-ß receptor inhibitor) or LY294002 (a PI3K inhibitor). Moreover, immunofluorescence results demonstrated that TGF-ß secreted by M2 macrophages could facilitate the expression of A2 biomarker S100A10 in AS; combined with the results of western blot, it was found that this effect was closely related to the activation of PI3K/Akt pathway in AS. In conclusion, TGF-ß secreted by M2 macrophages may induce the conversion of AS to the A2 phenotype through the activation of the PI3K/Akt pathway.

Multiple strategies enhance the efficacy of MSCs transplantation for spinal cord injury.

Spinal cord injury (SCI) is a serious complication of the central nervous system (CNS) after spine injury, often resulting in severe sensory, motor, and autonomic dysfunction below the level of injury. To date, there is no effective treatment strategy for SCI. Recently, stem cell therapy has brought hope to patients with neurological diseases. Mesenchymal stem cells (MSCs) are considered to be the most promising source of cellular therapy after SCI due to their immunomodulatory, neuroprotective and angiogenic potential. Considering the limited therapeutic effect of MSCs due to the complex pathophysiological environment following SCI, this paper not only reviews the specific mechanism of MSCs to facilitate SCI repair, but also further discusses the research status of these pluripotent stem cells combined with other therapeutic approaches to promote anatomical and functional recovery post-SCI.

Advances in the research of the role of macrophage/microglia polarization-mediated inflammatory response in spinal cord injury.

It is often difficult to regain neurological function following spinal cord injury (SCI). Neuroinflammation is thought to be responsible for this failure. Regulating the inflammatory response post-SCI may contribute to the recovery of neurological function. Over the past few decades, studies have found that macrophages/microglia are one of the primary effector cells in the inflammatory response following SCI. Growing evidence has documented that macrophages/microglia are plastic cells that can polarize in response to microenvironmental signals into M1 and M2 macrophages/microglia. M1 produces pro-inflammatory cytokines to induce inflammation and worsen tissue damage, while M2 has anti-inflammatory activities in wound healing and tissue regeneration. Recent studies have indicated that the transition from the M1 to the M2 phenotype of macrophage/microglia supports the regression of inflammation and tissue repair. Here, we will review the role of the inflammatory response and macrophages/microglia in SCI and repair. In addition, we will discuss potential molecular mechanisms that induce macrophage/microglia polarization, with emphasis on neuroprotective therapies that modulate macrophage/microglia polarization, which will provide new insights into therapeutic strategies for SCI.

Novel compound heterozygous variants in the LHX3 gene caused combined pituitary hormone deficiency: A case report.

BACKGROUND: Combined pituitary hormone deficiency 3 (CPHD3; OMIM: 221750) is caused by mutations within the LHX3 gene (OMIM: 600577), which located on the subtelomeric region of chromosome 9 at band 9q34.3, has seven coding exons and six introns. LIM homeobox (LHX) 3 protein is the key regulator of pituitary development in fetal life. CASE SUMMARY: We have diagnosed and treate an 11-year-old boy with combined pituitary hormone deficiency (CPHD). The main clinical manifestations were pituitary hormone deficiency, hydrocele of the tunica vaginalis, pituitary dwarfism, gonadal dysplasia, micropenis, clonic convulsion, and mild facial dysmorphic features. We collected peripheral blood from the patient, the patient's older brother, as well as their parents, and sequenced them by using high-throughput whole-exosome sequencing, which was verified by Sanger sequencing. The results showed that there were two compound heterozygous variants of c.613G>C (p.V205L) and c.220T>C (p.C74R) in the LHX3 gene. c.613G>C (p.V205L) was inherited from his mother and c.220T>C (p.C74R) from his father. His brother also has both variants and symptoms. CONCLUSION: This study reported ununreported genetic mutations of LHX3, and recorded the treatment process of the patients, providing data for the diagnosis and treatment of CPHD.

PBMSCs transplantation facilitates functional recovery after spinal cord injury by regulating microglia/macrophages plasticity.

BACKGROUND: Stem cell therapy has been proven as one of the promising strategies for treating spinal cord injury (SCI). However, the role of peripheral blood-derived mesenchymal stem cells (PBMSCs) in animal models of SCI has not been fully uncovered. This study aimed to investigate whether transplanted PBMSCs could inhibit neuroinflammation and then promote the functional recovery by shifting the microglia/macrophages phenotype from M1 to M2 at the site of injury after SCI. METHODS: PBMSCs harvested from peripheral blood were analyzed by morphology and phenotype. Rat models of SCI were administrated with PBMSCs 1 week after injury. Inclined plane test and Basso-Beattie-Bresnahan (BBB) scores were used for assessing the functional recovery. Enzyme-linked immunosorbent assay (ELISA), reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and flow cytometry (FCM) were performed on days 3, 7, 14, 28 and 56 after PBMSCs transplantation. RESULTS: PBMSCs were plastic-adherent and fibroblast-like with positive expression of cluster of differentiation (CD)29, CD90 and CD44. ELISA and RT-qPCR both showed a lower expression of pro-inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α while a higher expression of anti-inflammatory cytokines IL-10 and transforming growth factor (TGF)-ß1 after PBMSCs transplantation. This was associated with increased numbers of M2 microglia/macrophages and decreased numbers of M1 microglia/macrophages. These changes taken together were associated with the functional recovery in PBMSCs groups. CONCLUSIONS: Administration of PBMSCs following SCI may provide an anti-inflammatory and reparative micro-environment for locomotive recovery by shifting microglia/macrophages phenotype from M1 towards M2.

Regulatory Role of Mesenchymal Stem Cells on Secondary Inflammation in Spinal Cord Injury.

Spinal cord injury (SCI) is a catastrophic condition with high morbidity and mortality that still lacks effective therapeutic strategies. It is well known that the most important stage in SCI pathogenesis is secondary injury, and among the involved mechanisms, the inflammatory cascade is the main contributor and directly influences neurological function recovery. In recent years, increasing evidence has shown that mesenchymal stem cells (MSCs) transplantation is a promising immunomodulatory strategy. Transplanted MSCs can regulate macrophage-, astrocyte-, and T lymphocyte-mediated neuroinflammation and help create a microenvironment that facilitates tissue repair and regeneration. This review focuses on the effects of different types of immune cells and MSCs, specifically the immunoregulatory capacity of MSCs in SCI and repair. We will also discuss how to exploit MSCs transplantation to regulate immune cells and develop novel therapeutic strategies for SCI.

Neuroinflammation and Scarring After Spinal Cord Injury: Therapeutic Roles of MSCs on Inflammation and Glial Scar.

Transected axons are unable to regenerate after spinal cord injury (SCI). Glial scar is thought to be responsible for this failure. Regulating the formation of glial scar post-SCI may contribute to axonal regrow. Over the past few decades, studies have found that the interaction between immune cells at the damaged site results in a robust and persistent inflammatory response. Current therapy strategies focus primarily on the inhibition of subacute and chronic neuroinflammation after the acute inflammatory response was executed. Growing evidences have documented that mesenchymal stem cells (MSCs) engraftment can be served as a promising cell therapy for SCI. Numerous studies have shown that MSCs transplantation can inhibit the excessive glial scar formation as well as inflammatory response, thereby facilitating the anatomical and functional recovery. Here, we will review the effects of inflammatory response and glial scar formation in spinal cord injury and repair. The role of MSCs in regulating neuroinflammation and glial scar formation after SCI will be reviewed as well.