Toll-Like Receptors (TLRs) and their potential therapeutic applications in diabetic neuropathy

Design, synthesis, in vitro and in vivo biological evaluation of pterostilbene derivatives for anti-inflammation therapy

Pterostilbene (PST) is a naturally derived stilbene compound in grapes, blueberries, and other fruits. It is also a natural dietary compound with a wide range of biological activities such as antioxidant, anti-inflammatory, antitumor, and so on. Structural modifications based on the chemical scaffold of the pterostilbene skeleton are of great importance for drug discovery. In this study, pterostilbene skeletons were used to design novel anti-inflammatory compounds with high activity and low toxicity. A total of 30 new were found and synthesised, and their anti-inflammatory activity and safety were screened. Among them, compound E2 was the most active (against NO: IC50 = 0.7 μM) than celecoxib. Further studies showed that compound E2 exerted anti-inflammatory activity by blocking LPS-induced NF-κB/MAPK signalling pathway activation. In vivo experiments revealed that compound E2 had a good alleviating effect on acute colitis in mice. In conclusion, compound E2 may be a promising anti-inflammatory lead compound.

Study on anti-inflammatory effect of Shangkehuangshui in vitro and in vivo based on TLR4/TLR2-NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Shangkehuangshui (SK) has been traditionally used to treat traumatic injury, soft tissue and bone injury in Foshan hospital of traditional Chinese medicine for more than 60 years, which composed of many Chinese herbs such as Coptis chinensis Franch., Gardenia jasminoides Ellis, Phellodendron chinense Schneid. and etc. SK exhibits heat-clearing and detoxifying, enhancing blood circulation to eliminate blood stasis properties, and demonstrates noteworthy clinical efficacy. Nevertheless, the underlying mechanism remains uncertain.

AIM OF THE STUDY

The early study found that SK had good anti-inflammatory effects in acute soft tissue injury model. This research is to verify the anti-inflammatory properties of SK both in vitro and in vivo via TLR4/TLR2-NF-κB signaling pathway, to clarify the underlying mechanisms responsible for the curative effect of SK.

METHODS

The RAW264.7 cells inflammatory model was established with lipopolysaccharide (LPS) in vitro. NO and TNF-α, IL-6, IL-1β were determined with Griess method and ELISA method respectively. The mRNA and protein expression levels of TLR4/TLR2-NF-κB pathway were evaluated by qPCR and Western blot method. In vivo experiment, chronic soft tissue injury rat models were established by tracking gastrocnemius muscle with electrical stimulation, then local appearance and pathological changes were observed and recorded, the contents of inflammatory factors in serum and tissue were performed. Moreover, we also measured and contrasted the expression of TLR4/TLR2-NF-κB related factors.

RESULTS

SK effectively inhibited the LPS-induced generation of inflammatory cytokines, including NO, TNF-α, IL-6 and IL-1β in RAW264.7 cells, and significantly suppressed the expression of TLR4, TLR2, MyD88, IκB, and NF-κB. In vivo, SK remarkably decreased the damage appearance scores after 4 and 14 days of administration and inhibit the quantity of NO and leukocytes present in the serum. Additionally, the inflammatory infiltration in the pathological section was alleviated, myofibrillar hyperplasia and blood stasis were reduced. SK markedly downregulated NO, TNF-α, IL-6 and IL-1β in injured tissues of rats, also declined the expression of TLR4, TLR2, MyD88, IκB, NF-κB, IL-6, TNF-α and IL-1β.

CONCLUSION

This study revealed that SK had obvious effects of anti-inflammatory actions in vivo and vitro, effectively reduced acute and chronic soft tissue injury in clinical, this might be attributed to inhibit the TLR4/TLR2-NF-κB pathway, further inhibit the expression of downstream relevant pro-inflammatory cytokines.

How inflammation dictates diabetic peripheral neuropathy: An enlightening review

BACKGROUND

Diabetic peripheral neuropathy (DPN) constitutes a debilitating complication associated with diabetes. Although, the past decade has seen rapid developments in understanding the complex etiology of DPN, there are no approved therapies that can halt the development of DPN, or target the damaged nerve. Therefore, clarifying the pathogenesis of DPN and finding effective treatment are the crucial issues for the clinical management of DPN.

AIMS

This review is aiming to summary the current knowledge on the pathogenesis of DPN, especially the mechanism and application of inflammatory response.

METHODS

We systematically summarized the latest studies on the pathogenesis and therapeutic strategies of diabetic neuropathy in PubMed.

RESULTS

In this seminal review, the underappreciated role of immune activation in the progression of DPN is scrutinized. Novel insights into the inflammatory regulatory mechanisms of DPN have been unearthed, illuminating potential therapeutic strategies of notable clinical significance. Additionally, a nuanced examination of DPN's complex etiology, including aberrations in glycemic control and insulin signaling pathways, is presented. Crucially, an emphasis has been placed on translating these novel understandings into tangible clinical interventions to ameliorate patient outcomes.

CONCLUSIONS

This review is distinguished by synthesizing cutting-edge mechanisms linking inflammation to DPN and identifying innovative, inflammation-targeted therapeutic approaches.

Potential role of Schwann cells in neuropathic pain

Neuropathic pain (NPP) is a common syndrome associated with most forms of disease, which poses a serious threat to human health. NPP may persist even after the nociceptive stimulation is eliminated, and treatment is extremely challenging in such cases. Schwann cells (SCs) form the myelin sheaths around neuronal axons and play a crucial role in neural information transmission. SCs can secrete trophic factors to nourish and protect axons, and can further secrete pain-related factors to induce pain. SCs may be activated by peripheral nerve injury, triggering the transformation of myelinated and non-myelinated SCs into cell phenotypes that specifically promote repair. These differentiated SCs provide necessary signals and spatial clues for survival, axonal regeneration, and nerve regeneration of damaged neurons. They can further change the microenvironment around the regions of nerve injury, and relieve the pain by repairing the injured nerve. Herein, we provide a comprehensive overview of the biological characteristics of SCs, discuss the relationship between SCs and nerve injury, and explore the potential mechanism of SCs and the occurrence of NPP. Moreover, we summarize the feasible strategies of SCs in the treatment of NPP, and attempt to elucidate the deficiencies and defects of SCs in the treatment of NPP.

Prevalence of Orthopedic Pains in Children and Adolescents: A Systematic Review and Meta-analysis

Context

Musculoskeletal disorders are among the main causes of death and disability and can impose high costs on individuals and countries. Considering the importance of pain, the present meta-analysis study aimed to investigate the prevalence of orthopedic pains in Iranian children and adolescents.

Methods

The present study was reported in line with PRISMA. The searching process was carried out using keywords, including adolescents, pain, youth, school-age children, shoulder pain, neck pain, shoulder, and neck, AND/OR operators for the articles published during 2000 and 2022 in Scopus, Embase, PubMed, Scientific Information Database, Magiran, International Statistical Institute, and Islamic World Science Citation Center databases. This study reviewed the articles that reported the prevalence of orthopedic pains (i.e., wrists/hands, shoulders, elbows, and knees) among the 5-18-year age group in Iran and extracted their results. Two researchers conducted the search quite independently and extracted the necessary data using a researcher-made checklist. The collected data were analyzed using Comprehensive Meta-Analysis software (CMA3).

Results

Initially, 418 articles were identified, and 14 articles were entered into the systematic review stage. The prevalence rates of pains related to wrists/hands, shoulders, elbows, and knees were 6.6 (95% confidence interval [CI]: 3.2 - 13.0), 26.9 (95% CI: 17.0 - 39.7), 2.9 (95% CI: 1.3 - 6.3), and 6.6 (95% CI: 3.0 - 14.2), respectively.

Conclusions

The prevalence of shoulder and knee pains in individuals under 18 years in Iran was high. Therefore, it is necessary to make necessary interventions and take preventive measures.

Identification of Adipogenesis Subgroups and Immune Infiltration Characteristics in Diabetic Peripheral Neuropathy

Dysregulation of adipogenesis is related to diabetic peripheral neuropathy (DPN) pathogenesis, which may be mediated by immune infiltration. Nevertheless, the expression patterns of multiple adipogenesis-related genes and the differences of immune infiltration in different lipid metabolism levels remain unknown. GSE95849, a gene expression matrix containing DPN patients and healthy participants, was downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed adipogenesis-related genes (DEARGs) were screened by overlapping the adipogenesis-related genes with differentially expressed genes (DEGs). DPN patients from GSE24290 and GSE148059 were divided into two adipogenesis subgroups according to the expression of DEARGs. The single-sample gene set enrichment analysis (ssGSEA) was used to estimate the abundance of the immune cells between two subgroups. The analysis of immune infiltration suggested that a variety of immune cells and immune processes were elevated in the high expression group of DEARGs. The differentially expressed genes of the two subgroups were mainly enriched in biological processes and signaling pathways related to lipid metabolism. PPARG, FABP4, LIPE, FASN, SCD, DGAT2, PNPLA2, ADIPOQ, LEP, and CEBPA were identified as the hub genes of the two subgroups, whose related transcription factors (TFs) and miRNAs were predicted. An immunohistochemical assay was used to verify the expression of hub genes in DPN nerve tissues. Our comprehensive analysis of adipogenesis subgroups in DPN illustrated that different expression patterns of DEARGs may lead to different immune and inflammatory states. The identification of DEARGs may help to further distinguish the different characteristics of DPN patients and lay the foundation for targeted treatment. Our findings may bring a novel perspective to the diagnosis and treatment of DPN patients.

Lipopolysaccharide-Induced Model of Neuroinflammation: Mechanisms of Action, Research Application and Future Directions for Its Use

Despite advances in antimicrobial and anti-inflammatory therapies, inflammation and its consequences still remain a significant problem in medicine. Acute inflammatory responses are responsible for directly life-threating conditions such as septic shock; on the other hand, chronic inflammation can cause degeneration of body tissues leading to severe impairment of their function. Neuroinflammation is defined as an inflammatory response in the central nervous system involving microglia, astrocytes, and cytokines including chemokines. It is considered an important cause of neurodegerative diseases, such as Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Lipopolysaccharide (LPS) is a strong immunogenic particle present in the outer membrane of Gram-negative bacteria. It is a major triggering factor for the inflammatory cascade in response to a Gram-negative bacteria infection. The use of LPS as a strong pro-inflammatory agent is a well-known model of inflammation applied in both in vivo and in vitro studies. This review offers a summary of the pathogenesis associated with LPS exposure, especially in the field of neuroinflammation. Moreover, we analyzed different in vivo LPS models utilized in the area of neuroscience. This paper presents recent knowledge and is focused on new insights in the LPS experimental model.

The crosstalk among TLR2, TLR4 and pathogenic pathways; a treasure trove for treatment of diabetic neuropathy

Diabetes is correlated with organ failures as a consequence of microvascular diabetic complications, including neuropathy, nephropathy, and retinopathy. These difficulties come with serious clinical manifestations and high medical costs. Diabetic neuropathy (DN) is one of the most prevalent diabetes complications, affecting at least 50% of diabetic patients with long disease duration. DN has serious effects on patients' life since it interferes with their daily physical activities and causes psychological comorbidities. There are some potential risk factors for the development of neuropathic injuries. It has been shown that inflammatory mechanisms play a pivotal role in the progression of DN. Among inflammatory players, TLR2 and TLR4 have gained immense importance because of their ability in recognizing distinct molecular patterns of invading pathogens and also damage-associated molecular patterns (DAMPs) providing inflammatory context for the progression of a wide array of disorders. We, therefore, sought to explore the possible role of TLR2 and TLR4 in DN pathogenesis and if whether manipulating TLRs is likely to be successful in fighting off DN.