Inflammation and regeneration最新文献

Background: The clinical application of mesenchymal stem cells (MSCs) has garnered attention due to their remarkable capacity to differentiate into adipocytes, chondrocytes, and osteoblasts. However, the quality of MSC culture varies from batch to batch, which poses challenges in ensuring consistent cellular quality across batches. Consequently, it becomes imperative to identify specific markers that can distinguish superior and slightly inferior MSCs.

Methods: Human bone marrow-derived MSC clones were isolated and subjected to flow cytometry analysis to assess the expression of NRP2, VEGFR, and plexinA1. The osteogenic and adipogenic differentiation potentials were evaluated using Alizarin Red S and Oil Red O staining, respectively. Furthermore, the migration capacity was assessed through the scratch healing assay.

Results: Nine out of twenty MSC clones significantly expressed NRP2. NRP2-expressing MSC clones (NRP2⁺ MSCs) retained superior proliferation and differentiation capacities, along with increased migratory capacity compared to non-expressing MSC clones (NRP2^- MSCs). In addition, the activation of VEGF-C/NRP2 signaling augmented the potential of MSCs in cell proliferation and differentiation.

Conclusion: In contrast to NRP2^- MSCs, NRP2⁺ MSCs exhibited superior proliferation, differentiation abilities, and migration capacity. Moreover, the stimulation of VEGF-C/NRP2 signaling further enhanced the proliferation and differentiation rates, indicating a role of NRP2 in the maintenance of MSC stemness. Hence, NRP2 holds potential as a cell surface marker for identifying beneficial MSCs for regenerative medicine.

Peripheral nerve injuries (PNI) occur in approximately 13-23 per 100,000 individuals, predominantly affecting young and middle-aged adults. These injuries often require a lengthy recovery period, placing substantial burdens on healthcare systems and national economies. Current treatment strategies have not significantly shortened this lengthy regenerative process, highlighting the urgent need for innovative therapeutic interventions. Chemokines were originally noted for their powerful ability to recruit immune cells; however, as research has advanced, it has become increasingly evident that their role in peripheral nerve repair has been underestimated. In this review, we provide the first comprehensive overview of chemokine expression and activity during peripheral nerve injury and regeneration. We summarize the existing literature on chemokine family members, detailing their expression patterns and localization in injured nerves to facilitate further mechanistic investigations. For chemokines that remain controversial, such as CXCL1 and CCL2, we critically examine experimental methodologies and discuss factors underlying conflicting results, ultimately affirming their contributions to promoting nerve repair. Importantly, we highlight the dual nature of chemokines: in the early stages of injury, they initiate reparative responses, activate Schwann cells, regulate Wallerian degeneration, and support nerve recovery; but when the axons are connected and the repair enters the later stages, their persistent proinflammatory effects during later stages may impede the healing process. Additionally, we emphasize that certain chemokines, including CXCL5, CXCL12, and CCL2, can act directly on neurons/axons, thereby accelerating axonal regeneration. Future research should focus on precisely mapping the localization and temporal expression profiles of these chemokines and exploring therapeutic approaches.

Background: Ectopic fat is also formed in muscles as well as the liver, where adipose-derived mesenchymal stem cells (ADSCs) promote adipogenesis. On the other hand, after muscle injury, muscle satellite cells (SCs) contribute to muscle repair through myodifferentiation. Human ADSCs are multipotent stem cells, but it remains unclear whether they are involved in myoblast differentiation. The aim is to find a novel myogenic cytokine and its signaling pathway that promotes the differentiation of human ADSCs-a potential source of new muscle precursor cells-into myoblasts.

Methods: An array kit was used to detect cytokines produced by ADSCs. After treating ADSCs with the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-aza-C) and different JAK inhibitors, MyHC1, a myodifferentiation marker, was detected by immunofluorescence staining and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression status of signaling molecules was determined by Western blotting and the recruitment of transcription factors to the MYOG promoter by chromatin immunoprecipitation (ChIP).

Results: IL-6 was detected at high concentrations in the culture supernatant of ADSCs. ADSCs stimulated with 5-aza-C became strongly positive for MyHC1 on day 21 post-stimulation. When co-stimulated with 5-aza-C and IL-6/sIL-6R, ADSCs became positive for MyHC1 protein and upregulated MYOG mRNA as early as day 14 post-stimulation. Co-stimulation with 5-aza-C and IL-6/sIL-6R resulted in phosphorylation of STAT1 and STAT3. The addition of a JAK2 inhibitor, but not JAK1/3 inhibitors, abolished the MyHC1 positivity and phosphorylation of STAT1 and STAT3. Co-stimulation with 5-aza-C and IL-6/sIL-6R during the myogenesis process resulted in the recruitment of STAT1, but not STAT3, to the MYOG promoter. Myoblast differentiation induced by stimulation with 5-aza-C was enhanced by activation of the IL-6/JAK2/STAT1/MYOG pathway.

Conclusions: Therefore, sustained IL-6/JAK2/STAT1 activation may serve as an important driver of human ADSC differentiation into myoblast, suggesting an important candidate signaling pathway for ameliorating muscle atrophy.

Background: Wound healing is a complex physiological process essential for restoring tissue integrity following various injuries, ranging from minor, everyday incidents to post-surgical complications. Emerging studies have demonstrated that lactic acid bacteria (LAB) can offer benefits beyond gut health, extending their positive effects on skin health. This study investigated the potential of Lactobacillus reuteri NCHBL-005, a honeybee-derived probiotic strain, to enhance fibroblast-mediated wound healing.

Method: L929 cells and mouse embryonic fibroblasts (MEFs) were utilized as models to specifically target fibroblasts. To assess the wound healing potential in vitro, a scratch assay was performed, providing insights into wound closure. Additionally, we created wound models in mice to evaluate the in vivo effects of the treatment.

Results: Our results showed that L. reuteri NCHBL-005 significantly accelerated wound closure in L929 fibroblast compared to other lactobacilli and exhibited superior efficacy in activating the mitogen-activated protein kinase (MAPK) pathway. Through MAPK inhibition assays, we confirmed that the wound healing effects of L. reuteri NCHBL-005 were MAPK-dependent, promoting fibroblast proliferation and differentiation. Notably, L. reuteri NCHBL-005 treatment did not facilitate wound healing in MEF cells derived from Toll-like-receptor 2 knockout (TLR2^-/-) mice, highlighting the critical role of TLR2 in this mechanism. In vivo studies further corroborated these findings, in which topical administration of L. reuteri NCHBL-005 enhanced wound healing and stimulated fibroblast proliferation and activation, as confirmed by histopathological analysis.

Conclusion: These findings revealed that L. reuteri NCHBL-005 activates fibroblasts through TLR2 stimulation and subsequent MAPK pathway activation, suggesting its potential as a promising therapeutic candidate for wound management.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can lead to severe coronavirus disease 2019 (COVID-19), which is characterized by cytokine storm and organ dysfunction. The spike S1 subunit induces inflammatory cytokine production, but the immune cell subsets that respond to S1 stimulation and contribute to disease severity remain unclear.

Methods: We analyzed serum samples and peripheral blood mononuclear cells (PBMCs) from patients with COVID-19 (moderate: n = 7; severe: n = 25) and healthy controls (n = 38). Using mass cytometry (cytometry by time-of-flight; CyTOF), we analyzed immune cell responses to S1 subunit stimulation in PBMCs from healthy donors and patients with COVID-19. We examined correlations among identified cell populations, serum cytokine levels, and clinical parameters.

Results: Serum S1 subunit levels correlated with disease severity and inflammatory cytokine concentrations. S1 subunit stimulation induced dose-dependent cytokine production from PBMCs, predominantly from myeloid cells. CyTOF analysis identified classical monocytes with high CD147 expression (CD147hi cMono) as the primary source of S1-induced cytokines. The proportion of CD147hi cMono increased significantly in severe COVID-19 and decreased with clinical improvement. The frequency of CD147hi cMono showed a stronger positive correlation with clinical severity markers in younger patients compared to older patients.

Conclusions: CD147hi cMono are the primary cellular source of S1-induced inflammatory cytokines and may serve as potential biomarkers for monitoring COVID-19 severity and treatment response.

Ischemic stroke triggers inflammation that promotes neuronal injury, leading to disruption of neural circuits and exacerbated neurological deficits in patients. Immune cells contribute to not only the acute inflammatory responses but also the chronic neural repair. During the post-stroke recovery, reparative immune cells support the neural circuit reorganization that occurs around the infarct region to connect broad brain areas. This review highlights the time-dependent changes of neuro-immune interactions and reorganization of neural circuits after ischemic brain injury. Understanding the molecular mechanisms involving immune cells in acute inflammation, subsequent neural repair, and neuronal circuit reorganization that compensate for the lost brain function is indispensable to establish treatment strategies for stroke patients.

Spatial transcriptomics is a cutting-edge technology that analyzes gene expression at the cellular level within tissues while integrating spatial location information. This concept, which combines high-plex RNA sequencing with spatial data, emerged in the early 2010s. Spatial transcriptomics has rapidly expanded with the development of technologies such as in situ hybridization, in situ sequencing, in situ spatial barcoding, and microdissection-based methods. Each technique offers advanced mapping resolution and precise spatial assessments at the single-cell level. Over the past decade, the use of spatial transcriptomics on clinical samples has enabled researchers to identify gene expressions in specific diseased foci, significantly enhancing our understanding of cellular interactions and disease processes. In the field of rheumatology, the complex and elusive pathophysiology of diseases such as rheumatoid arthritis, systemic lupus erythematosus, and Sjögren's syndrome remains a challenge for personalized treatment. Spatial transcriptomics provides insights into how different cell populations interact within disease foci, such as the synovial tissue, kidneys, and salivary glands. This review summarizes the development of spatial transcriptomics and current insights into the pathophysiology of autoimmune rheumatic diseases, focusing on immune cell distribution and cellular interactions within tissues. We also explore the potential of spatial transcriptomics from a clinical perspective and discuss the possibilities for translating this technology to the bedside.

During human evolution, some genes were lost or silenced from the genome of hominins. These missing genes might be the key to the evolution of humans' unique cognitive skills. An inactivation mutation in CMP-N-acetylneuraminic acid hydroxylase (CMAH) was the result of natural selection. The inactivation of CMAH protected our ancestors from some pathogens and reduced the level of N-glycolylneuraminic acid (Neu5Gc) in brain tissue. Interestingly, the low level of Neu5Gc promoted the development of brain tissue, which may have played a role in human evolution. As a xenoantigen, Neu5Gc may have been involved in brain evolution by affecting neural conduction, neuronal development, and aging.

Background: Recent evidence suggests that clonally expanded cytotoxic T cells play a role in various autoimmune diseases. Late-onset rheumatoid arthritis (LORA) exhibits unique characteristics compared to other RA forms, suggesting distinct immunological mechanisms. This study aimed to examine the involvement of cytotoxic T cells in LORA.

Methods: Fresh peripheral blood samples were collected from 78 treatment-naïve active RA patients, 12 with difficult-to-treat RA, and 16 healthy controls. Flow cytometry was employed to measure the proportions of CX3CR1⁺cytotoxic CD4⁺ and CD8⁺ T cells in these samples. Additionally, immunohistochemical staining was performed on lymphoid node and synovial biopsy samples from patients with RA.

Results: CX3CR1⁺cytotoxic CD4⁺ T cells were specifically increased in untreated, active patients with LORA, displaying features of CXCR3^mid age-associated T helper cells known as "ThA". CX3CR1⁺CD4⁺ T cells were identified as a cytotoxic ThA subset, as nearly all of these cells specifically expressed granzyme B. These cells were observed in enlarged lymph nodes and were found to infiltrate synovial tissues from patients with LORA. The proportions of CX3CR1⁺CD4⁺ T cells positively correlated with arthritis activity in LORA. The number of cells decreased after treatment with methotrexate, tumor necrosis factor inhibitors, and interleukin-6 inhibitors, whereas T-cell activation modulators did not affect them. Moreover, PD-1⁺CD38⁺CX3CR1⁺CD4⁺ T cells were identified as a treatment-resistant T cell subset that was characteristically increased in difficult-to-treat RA. CX3CR1⁺CD8⁺ T cells showed no significant difference between RA patients and healthy individuals, and no correlation with disease activity was observed. However, a correlation with age was observed in RA patients.

Conclusions: Our findings suggest that the immunopathogenesis of RA differs by age of onset, with CX3CR1⁺ age-associated cytotoxic CD4⁺ T cells playing a significant role in LORA. Additionally, the presence of a specific CX3CR1⁺ T cell subset may be linked to treatment resistance.

Background: The incidence of periodontitis is high in older individuals. However, its impact on multi-organ frailty remains unclear. We developed mouse models with varying severity and duration of periodontitis to examine its effects.

Methods: We generated mouse models with mild and severe periodontitis, categorizing the disease duration into 3-month and 5-month periods for analysis. The organs assessed for frailty included the gastrocnemius muscle, soleus muscle, brain, and femur.

Results: Our study found that periodontitis induced systemic inflammation resembling inflammaging and other symptoms characteristic of age-induced frailty. Notably, muscle impairment developed specifically in slow-twitch muscles, and the femur emerged as the most vulnerable bone, exhibiting reduced bone mineral density even with mild and short-duration periodontitis. This condition resulted in the co-occurrence of bone fragility and slow-twitch muscle dysfunction. Cognitive function assessment revealed increased activated microglia and decreased adult neurogenesis in the hippocampus, impairing spatial learning. Thus, periodontitis induced both physical and cognitive frailties. Therapeutic intervention for the periodontitis, which halted the exacerbation of bone resorption markers, did not restore femur bone mineral density.

Conclusion: This study underscores the role of periodontitis in inducing multifaceted organ frailty with vulnerability, varying by organ, and the necessity of early intervention, particularly regarding bone density loss.