Arachidonic acid derivatives and their role in peripheral nerve degeneration and regeneration

Bioinformatics Analysis of Differentially Expressed Genes in Carpal Tunnel Syndrome Using RNA Sequencing

Background

Carpal tunnel syndrome (CTS) is a common disease resulting from the median nerve entrapment at the wrist. Although CTS (prevalence=5%-10% in the general population) is the most common neuropathy, its molecular mechanisms need elucidation. We used bioinformatics to detect genes with differential expressions in CTS and introduce the molecular regulatory noncoding RNAs and signaling pathways involved.

Methods

The raw files of the RNA sequencing of CTS patients and controls were obtained from GEO (accession: GSE108023), and the samples were analyzed. Differentially expressed genes were isolated using DESeq2 R. Functional analyses were conducted on the signaling pathways, biological processes, molecular functions, and cellular components of the differentially expressed genes. Additionally, interactions between the most differentially expressed genes and miRNAs and lncRNAs were investigated bioinformatically.

Results

Upregulation and downregulation were observed in 790 and 922 genes, respectively. The signaling pathway analysis identified the metabolism pathways of arachidonic acid, linoleic acid, and tyrosine as the most significant pathways in CTS. Moreover, PLA2G2D and PLA2G2A with upregulated expressions and PLA2G2F, PLA2G4F, PLA2G4D, PLA2G3, and PLA2G4E with downregulated expressions were genes from the phospholipase family playing significant roles in the pathways. Further analyses demonstrated that hsa-miR-3150b-3p targeted PLA2G2A and PLA2G4F, and RP11-573D15.8-018 lncRNA had regulatory interactions with the aforementioned genes.

Conclusion

Molecular studies on CTS will clarify the involved signaling pathways and provide critical data for biomedical research, drug development, and clinical applications.

Effects of andiroba oil (Carapa guianensis aublet) on the immune system in inflammation and wound healing: A scoping review

ETHNOPHARMACOLOGICAL RELEVANCE

Andiroba seed oil (Carapa guianensis Aubl.) is widely used by traditional populations in tropical countries, especially in the Brazilian Amazon, because of its anti-inflammatory, antirheumatic, antiseptic, healing and antipyretic properties, among others, which makes it useful for the treatment, mainly, of skin afflictions and wounds.

AIM OF THE STUDY

To describe the modulation of the immune system by andiroba oil (Carapa guianensis Aubl.) in inflammation and wound healing.

MATERIALS AND METHODS

A scoping review was performed, following the recommendations of the Joanna Briggs Institute (JBI) and PRISMA for Scoping Reviews (PRISMA-ScR). As inclusion criteria, in vitro, in vivo, ex vivo, and clinical studies were selected, in Portuguese, English, or Spanish, in thirteen databases of published studies, gray literature, and references of the included studies, which deal with immune modulation by andiroba oil in the context of the various therapeutic applications that make use of its anti-inflammatory and wound healing properties. The selection of information sources was carried out by two independent reviewers between November 2022 and January 2023. The process of data extraction and evidence analysis was conducted by four pairs of independent reviewers between January and February 2023.

RESULTS

22 sources of evidence were included in this scoping review, mostly scientific articles published between 2005 and 2021 with in vivo sampling. The evidence suggests that andiroba oil reduces inflammation and promotes the healing of wounds of multiple etiologies by reducing leukocyte infiltration, increasing phagocytic activity, enhancing interleukin and inflammatory cytokine activity, promoting fibroblast recovery, increasing growth factors, reducing apoptotic cells, promoting reepithelialization, as well as promoting angiogenesis, reducing edema, and stimulating the production of glucocorticoids that alleviate pain. Additionally, different formulations of the oil (such as nanoemulsions, films and gels) are more effective in modulating inflammation and wound healing compared to in natura oil.

CONCLUSIONS

Evidence in the literature suggests that andiroba oil (Carapa guianensis Aubl.) has positive effects on immune modulation in inflammation and wound healing, which makes it a biocompound with high therapeutic potential.

Endothelial nitric oxide synthase Asp298Glu (894G/T) gene polymorphism as a possible risk factor for the coronary slow flow phenomenon among Iranians

Background

Mounting evidence indicates an association between endothelial dysfunction and the coronary slow flow phenomenon (CSFP). In the present study, we aimed to evaluate the possible role of endothelial nitric oxide synthase (eNOS) 894G/T and interleukin-1β (IL-1β) 315C/T polymorphisms as possible risk factors for CSFP.

Methods

This prospective study enrolled patients with CSFP and individuals with normal coronary arteries. Genotypes were assessed using regular polymerase chain reaction and direct Sanger-sequencing techniques.

Results

The study population consisted of 267 individuals: 180 patients with CSFP (49 women [27.2%]) at a median age of 55 (48–62) years and 87 controls with normal coronary arteries (56 women [64.4%]) at a median age of 47 (41–58) years. The allelic distribution of eNOS 894G/T was significantly associated with CSFP (odds ratio [OR], 1.58; 95% confidence interval (CI), 1.04–2.42; P = 0.03). This polymorphism increased the risk of CSFP under the dominant model (OR 1.73; 95% CI I.02–2.95; P = 0.04). However, the allelic frequencies (1.05; 95% CI 0.68–1.59; P = 0.83) and genotypic frequencies (0.88; 95% CI 0.52–1.49; P = 0.63) of the IL-1β 315C/T polymorphism were not associated with the incidence of CSFP in the Iranian population.

Conclusions

The CSFP and control groups were statistically different regarding the eNOS 894G/T polymorphism. Our findings also demonstrated that the IL-1β 315C/T polymorphism was not a risk factor for CSFP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02736-0.

Lipids in Pathophysiology and Development of the Membrane Lipid Therapy: New Bioactive Lipids

Membranes are mainly composed of a lipid bilayer and proteins, constituting a checkpoint for the entry and passage of signals and other molecules. Their composition can be modulated by diet, pathophysiological processes, and nutritional/pharmaceutical interventions. In addition to their use as an energy source, lipids have important structural and functional roles, e.g., fatty acyl moieties in phospholipids have distinct impacts on human health depending on their saturation, carbon length, and isometry. These and other membrane lipids have quite specific effects on the lipid bilayer structure, which regulates the interaction with signaling proteins. Alterations to lipids have been associated with important diseases, and, consequently, normalization of these alterations or regulatory interventions that control membrane lipid composition have therapeutic potential. This approach, termed membrane lipid therapy or membrane lipid replacement, has emerged as a novel technology platform for nutraceutical interventions and drug discovery. Several clinical trials and therapeutic products have validated this technology based on the understanding of membrane structure and function. The present review analyzes the molecular basis of this innovative approach, describing how membrane lipid composition and structure affects protein-lipid interactions, cell signaling, disease, and therapy (e.g., fatigue and cardiovascular, neurodegenerative, tumor, infectious diseases).

Increased TRPV4 expression in non-myelinating Schwann cells is associated with demyelination after sciatic nerve injury

Transient receptor potential vanilloid 4 (TRPV4) is a non-selective calcium-permeable cation channel that is widely expressed and activated in various neurons and glial cells in the nervous system. Schwann cells (SCs) are primary glia cells that wrap around axons to form the myelin sheath in the peripheral nervous system. However, whether TRPV4 is expressed and functions in SCs is unclear. Here, we demonstrate functional expression of TRPV4 in mouse SCs and investigated its physiological significance. Deletion of TRPV4 did not affect normal myelin development for SCs in sciatic nerves in mice. However, after sciatic nerve cut injury, TRPV4 expression levels were remarkably increased in SCs following nerve demyelination. Ablation of TRPV4 expression impaired the demyelinating process after nerve injury, resulting in delayed remyelination and functional recovery of sciatic nerves. These results suggest that local activation of TRPV4 could be an attractive pharmacological target for therapeutic intervention after peripheral nerve injury.

Feng et al. report that TRPV4 plays an important role in Schwann cells (SCs) during nerve demyelination and remyelination in mice. Using sciatic nerve cut injury mouse models, they find that TRPV4 expression is remarkably increased in demyelinating SCs during sciatic nerve injury; and ablation of TRPV4 expression impairs the demyelinating process after nerve injury, resulting in their delayed remyelination and functional recovery.

Magnetic resonance imaging of enhanced nerve repair with mesenchymal stem cells combined with microenvironment immunomodulation in neurotmesis

INTRODUCTION

The immuno-microenvironment of injured nerves adversely affects mesenchymal stem cell (MSC) therapy for neurotmesis. Magnetic resonance imaging (MRI) can be used noninvasively to monitor nerve degeneration and regeneration. The aim of this study was to investigate nerve repair after MSC transplantation combined with microenvironment immunomodulation in neurotmesis by using multiparametric MRI.

METHODS

Rats with sciatic nerve transection and surgical coaptation were treated with MSCs combined with immunomodulation or MSCs alone. Serial multiparametric MRI examinations were performed over an 8-week period after surgery.

RESULTS

Nerves treated with MSCs combined with immunomodulation showed better functional recovery, rapid recovery of nerve T2, fractional anisotropy and radial diffusivity values, and more rapid restoration of the fiber tracks than nerves treated with MSCs alone.

DISCUSSION

Transplantation of MSCs in combination with immunomodulation can exert a synergistic repair effect on neurotmesis, which can be monitored by multiparametric MRI.

Inflammation markers in the saliva of infants born from Zika-infected mothers: exploring potential mechanisms of microcephaly during fetal development

Zika virus (ZIKV) has emerged as one of the most medically relevant viral infections of the past decades; the devastating effects of this virus over the developing brain are a major matter of concern during pregnancy. Although the connection with congenital malformations are well documented, the mechanisms by which ZIKV reach the central nervous system (CNS) and the causes of impaired cortical growth in affected fetuses need to be better addressed. We performed a non-invasive, metabolomics-based screening of saliva from infants with congenital Zika syndrome (CZS), born from mothers that were infected with ZIKV during pregnancy. We were able to identify three biomarkers that suggest that this population suffered from an important inflammatory process; with the detection of mediators associated with glial activation, we propose that microcephaly is a product of immune response to the virus, as well as excitotoxicity mechanisms, which remain ongoing even after birth.

Transcriptomics Analysis of Porcine Caudal Dorsal Root Ganglia in Tail Amputated Pigs Shows Long-Term Effects on Many Pain-Associated Genes

Tail amputation by tail docking or as an extreme consequence of tail biting in commercial pig production potentially has serious implications for animal welfare. Tail amputation causes peripheral nerve injury that might be associated with lasting chronic pain. The aim of this study was to investigate the short- and long-term effects of tail amputation in pigs on caudal DRG gene expression at different stages of development, particularly in relation to genes associated with nociception and pain. Microarrays were used to analyse whole DRG transcriptomes from tail amputated and sham-treated pigs 1, 8, and 16 weeks following tail treatment at either 3 or 63 days of age (8 pigs/treatment/age/time after treatment; n = 96). Tail amputation induced marked changes in gene expression (up and down) compared to sham-treated intact controls for all treatment ages and time points after tail treatment. Sustained changes in gene expression in tail amputated pigs were still evident 4 months after tail injury. Gene correlation network analysis revealed two co-expression clusters associated with amputation: Cluster A (759 down-regulated) and Cluster B (273 up-regulated) genes. Gene ontology (GO) enrichment analysis identified 124 genes in Cluster A and 61 genes in Cluster B associated with both “inflammatory pain” and “neuropathic pain.” In Cluster A, gene family members of ion channels e.g., voltage-gated potassium channels (VGPC) and receptors e.g., GABA receptors, were significantly down-regulated compared to shams, both of which are linked to increased peripheral nerve excitability after axotomy. Up-regulated gene families in Cluster B were linked to transcriptional regulation, inflammation, tissue remodeling, and regulatory neuropeptide activity. These findings, demonstrate that tail amputation causes sustained transcriptomic expression changes in caudal DRG cells involved in inflammatory and neuropathic pain pathways.

Altered Lipid Metabolism in Blood Mononuclear Cells of Psoriatic Patients Indicates Differential Changes in Psoriasis Vulgaris and Psoriatic Arthritis

The aim of this study was to investigate possible stress-associated disturbances in lipid metabolism in mononuclear cells, mainly lymphocytes of patients with psoriasis vulgaris (Ps, n = 32) or with psoriatic arthritis (PsA, n = 16) in respect to the healthy volunteers (n = 16). The results showed disturbances in lipid metabolism of psoriatic patients reflected by different phospholipid profiles. The levels of non-enzymatic lipid metabolites associated with oxidative stress 8-isoprostaglandin F2α (8-isoPGF2α) and free 4-hydroxynonenal (4-HNE) were higher in PsA, although levels of 4-HNE-His adducts were higher in Ps. In the case of the enzymatic metabolism of lipids, enhanced levels of endocannabinoids were observed in both forms of psoriasis, while higher expression of their receptors and activities of phospholipases were detected only in Ps. Moreover, cyclooxygenase-1 (COX-1) activity was enhanced only in Ps, but cyclooxygenase-2 (COX-2) was enhanced both in Ps and PsA, generating higher levels of eicosanoids: prostaglandin E1 (PGE1), leukotriene B4 (LTB4), 13-hydroxyoctadecadienoic acid (13HODE), thromboxane B2 (TXB2). Surprisingly, some of major eicosanoids 15-d-PGJ₂ (15-deoxy-Δ12,14-prostaglandin J₂), 15-hydroxyeicosatetraenoic acid (15-HETE) were elevated in Ps and reduced in PsA. The results of our study revealed changes in lipid metabolism with enhancement of immune system-modulating mediators in psoriatic mononuclear cells. Evaluating further differential stress responses in Ps and PsA affecting lipid metabolism and immunity might be useful to improve the prevention and therapeutic treatments of psoriasis.

Successful reduction of inflammatory responses and arachidonic acid-cyclooxygenase 2 pathway in human pulmonary artery endothelial cells by silencing adipocyte fatty acid-binding protein

Background

Adipocyte fatty acid-binding protein, also known as aP2 or fatty acid-binding protein 4 (FABP4), plays an important role in inflammatory and metabolic responses in adipocytes and macrophages. Recent work has demonstrated that macrophage FABP4 integrates inflammatory and lipid metabolic responses, thereby contributing to the development of insulin resistance and atherosclerosis. However, it is not known whether FABP4 in human pulmonary artery endothelial cells(HPAECs) modulates inflammation.

Results

Here, we demonstrate that FABP4 and inflammatory cytokines are upregulated in lipopolysaccharide(LPS)-stimulated HPAECs. In addition, LPS increases the expression of molecules in the arachidonic acid(AA)–cyclooxygenase (COX) 2 signaling pathway in FABP4-expressing, but not FABP4-deficient, HPAECs.

Conclusions

Our findings demonstrate that silencing FABP4 could decrease inflammatory cytokines, which were reported to be expressed via the AA–COX2 pathway, in HPAECs. In addition, silencing FABP4 could inhibit the expression of molecules in the AA–COX2 pathways. So we speculate silencing FABP4 could decrease the inflammatory response in HPAECs, which involves in the AA–COX2 signaling pathway. Our study suggests that FABP4 could be a potential biomarker and intervention point for the inflammation-related disease in HPAECs such as pulmonary thromboembolism.

Antimicrobial Nanostructures for Neurodegenerative Infections

Nanostructures have been widely involved in changes in the drug delivery system. Nanoparticles have unique physicochemical properties, e.g., ultrasmall size, large surface area, and the ability to target specific actions. Various nanomaterials, like Ag, ZnO, Cu/CuO, and Al₂O₃, have antimicrobial activity. Basically, six mechanisms are involved in the production of antimicrobial activity, i.e., (1) destruction of the peptidoglycan layer, (2) release of toxic metal ions, (3) alteration of cellular pH via proton efflux pumps, (4) generation of reactive oxygen species, (5) damage of nuclear materials, and (6) loss of ATP production. Nanomedicine contributes to various pharmaceutical applications, like diagnosis and treatment of various ailments including microbial diseases. Furthermore, nanostructured antimicrobial agents are also involved in the treatment of the neuroinfections associated with neurodegenerative disorders. This chapter focuses on the nanostructure and nanomedicine of antimicrobial agents and their prospects for the possible management of infections associated with neurodegenerative disorders.

Increased arachidonic acid-containing phosphatidylcholine is associated with reactive microglia and astrocytes in the spinal cord after peripheral nerve injury

Peripheral nerve injury (PNI) triggers cellular and molecular changes in the spinal cord. However, little is known about how the polyunsaturated fatty acid-containing phosphatidylcholines (PUFA-PCs) are regulated in the spinal cord after PNI and the association of PUFA-PCs with the non-neuronal cells within in the central nervous system (CNS). In this study, we found that arachidonic acid-containing phosphatidylcholine (AA-PC), [PC(16:0/20:4)+K](+), was significantly increased in the ipsilateral ventral and dorsal horns of the spinal cord after sciatic nerve transection, and the increased expression of [PC(16:0/20:4)+K](+) spatiotemporally resembled the increase of reactive microglia and the astrocytes. From the lipidomics point of view, we conclude that [PC(16:0/20:4)+K](+) could be the main phospholipid in the spinal cord influenced by PNI, and the regulation of specific phospholipid molecule in the CNS after PNI is associated with the reactive microglia and astrocytes.

Functional recoveries of sciatic nerve regeneration by combining chitosan-coated conduit and neurosphere cells induced from adipose-derived stem cells

Suboptimal repair occurs in a peripheral nerve gap, which can be partially restored by bridging the gap with various biosynthetic conduits or cell-based therapy. In this study, we developed a combination of chitosan coating approach to induce neurosphere cells from human adipose-derived stem cells (ASCs) on chitosan-coated plate and then applied these cells to the interior of a chitosan-coated silicone tube to bridge a 10-mm gap in a rat sciatic nerve. Myelin sheath degeneration and glial scar formation were discovered in the nerve bridged by the silicone conduit. By using a single treatment of chitosan-coated conduit or neurosphere cell therapy, the nerve gap was partially recovered after 6 weeks of surgery. Substantial improvements in nerve regeneration were achieved by combining neurosphere cells and chitosan-coated conduit based on the increase of myelinated axons density and myelin thickness, gastrocnemius muscle weight and muscle fiber diameter, and step and stride lengths from gait analysis. High expressions of interleukin-1β and leukotriene B4 receptor 1 in the intra-neural scarring caused by using silicone conduits revealed that the inflammatory mechanism can be inhibited when the conduit is coated with chitosan. This study demonstrated that the chitosan-coated surface performs multiple functions that can be used to induce neurosphere cells from ASCs and to facilitate nerve regeneration in combination with a cells-assisted coated conduit.

Neuroinflammation and central nervous system regeneration in vertebrates

Injuries in the central nervous system (CNS) are one of the leading causes of mortality or persistent disabilities in humans. One of the reasons why humans cannot recover from neuronal loss is the limited regenerative capacity of their CNS. By contrast, non-mammalian vertebrates exhibit widespread regeneration in diverse tissues including the CNS. Understanding those mechanisms activated during regeneration may improve the regenerative outcome in the severed mammalian CNS. Of those mechanisms, recent evidence suggests that inflammation may be important in regeneration. In this review we compare the different events following acute CNS injury in mammals and non-mammalian vertebrates. We also discuss the involvement of the immune response in initiating regenerative programs and how immune cells and neural stem/progenitor cells (NSPCs) communicate.