Abnormal nuclear factor (NF)-kappaB signal pathway and aspirin inhibits tumor necrosis factor alpha-induced NF-kappaB activation in keloid fibroblasts

An updated review of the immunological mechanisms of keloid scars

Keloid is a type of disfiguring pathological scarring unique to human skin. The disorder is characterized by excessive collagen deposition. Immune cell infiltration is a hallmark of both normal and pathological tissue repair. However, the immunopathological mechanisms of keloid remain unclear. Recent studies have uncovered the pivotal role of both innate and adaptive immunity in modulating the aberrant behavior of keloid fibroblasts. Several novel therapeutics attempting to restore regulation of the immune microenvironment have shown variable efficacy. We review the current understanding of keloid immunopathogenesis and highlight the potential roles of immune pathway-specific therapeutics.

Effect of Mortalin on Scar Formation in Human Dermal Fibroblasts and a Rat Incisional Scar Model

Wound healing is a complicated cascading process; disequilibrium among reparative processes leads to the formation of pathologic scars. Herein, we explored the role of mortalin in scar formation and its association with the interleukin-1α receptor using in vitro and in vivo models. To investigate the effects of mortalin, we performed an MTT cell viability assay, qRT-PCR, and Western blot analyses, in addition to immunofluorescence and immunoprecipitation studies using cultured fibroblasts. A rat incisional wound model was used to evaluate the effect of a mortalin-specific shRNA (dE1-RGD/GFP/shMot) Ad vector in scar tissue. In vitro, the mortalin-treated human dermal fibroblast displayed a significant increase in proliferation of type I collagen, α-smooth muscle actin, transforming growth factor-β, phospho-Smad2/3-complex, and NF-κB levels. Immunofluorescence staining revealed markedly increased mortalin and interleukin-1α receptor protein in keloid tissue compared to those in normal tissue, suggesting that the association between mortalin and IL-1α receptor was responsible for the fibrogenic effect. In vivo, mortalin-specific shRNA-expressing Ad vectors significantly decreased the scar size and type-I-collagen, α-SMA, and phospho-Smad2/3-complex expression in rat incisional scar tissue. Thus, dE1-RGD/GEP/shMot can inhibit the TGF-β/α-SMA axis and NF-κB signal pathways in scar formation, and blocking endogenous mortalin could be a potential therapeutic target for keloids.

The m6A RNA Modification Modulates Gene Expression and Fibrosis-Related Pathways in Hypertrophic Scar

Purpose: To systematically analyze the overall m⁶A modification pattern in hyperplastic scars (HS). Methods: The m⁶A modification patterns in HS and normal skin (NS) tissues were described by m⁶A sequencing and RNA sequencing, and subsequently bioinformatics analysis was performed. The m⁶A-related RNA was immunoprecipitated and verified by real-time quantitative PCR. Results: The appearance of 14,791 new m⁶A peaks in the HS sample was accompanied by the disappearance of 7,835 peaks. The unique m⁶A-related genes in HS were thus associated with fibrosis-related pathways. We identified the differentially expressed mRNA transcripts in HS samples with hyper-methylated or hypo-methylated m⁶A peaks. Conclusion: This study is the first to map the m⁶A transcriptome of human HS, which may help clarify the possible mechanism of m⁶A-mediated gene expression regulation.

Therapeutic Strategies by Regulating Interleukin Family to Suppress Inflammation in Hypertrophic Scar and Keloid

Hypertrophic scar (HS) and keloid are fibroproliferative disorders (FPDs) of the skin due to aberrant wound healing, which cause disfigured appearance, discomfort, dysfunction, psychological stress, and patient frustration. The unclear pathogenesis behind HS and keloid is partially responsible for the clinical treatment stagnancy. However, there are now increasing evidences suggesting that inflammation is the initiator of HS and keloid formation. Interleukins are known to participate in inflammatory and immune responses, and play a critical role in wound healing and scar formation. In this review, we summarize the function of related interleukins, and focus on their potentials as the therapeutic target for the treatment of HS and keloid.

Increased sensitivity to TNF-α promotes keloid fibroblast hyperproliferation by activating the NF-κB, JNK and p38 MAPK pathways

Hyperproliferation of fibroblasts is the main cause of keloid formation. However, the pathogenesis of keloids has yet to be fully elucidated. Tumor necrosis factor (TNF)-α may play an important role in the formation and proliferation of keloids, as it is implicated in the pathogenesis of various fibrous disorders. In the present study, the expression level of TNF-α and its receptors, soluble TNF receptor (sTNFR)1 and sTNFR2, in the peripheral blood and skin tissues was detected by ELISA, reverse transcription-quantitative PCR or immunohistochemistry. There was no statistically significant difference in the expression of TNF-α and sTNFR2 in the peripheral blood and skin tissues between patients with keloids and healthy participants (P>0.05), while the sTNFR1 mRNA level in fibroblasts cultured in vitro and its protein level in keloid skin samples were significantly higher compared with those in normal skin (P<0.05). Subsequently, TNF-α recombinant protein was used to treat keloid-derived and normal skin fibroblasts, and it was observed that TNF-α promoted the proliferation of keloid fibroblasts (KFs), but had little effect on normal skin fibroblasts. Furthermore, it was observed that TNF-α stimulation led to the activation of the nuclear factor (NF)-κB, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways in KFs. In conclusion, KFs exhibited increased expression of sTNFR1, which may contribute to the increased sensitivity to TNF-α, resulting in low concentrations of TNF-α activating the NF-κB, JNK and p38 MAPK pathways, thereby promoting the sustained and excessive proliferation of KFs.

Adiponectin, but Not TGF-β1, CTGF, IL-6 or TNF-α, May Be a Potential Anti-Inflammation and Anti-Fibrosis Factor in Keloid

INTRODUCTION

Numerous studies have elucidated adiponectin as a negative impact on inflammation and tissue fibrosis. However, little is known about the relevance between adiponectin and inflammatory factors in keloid.

METHODS

To clarify whether adiponectin plays a role in the inflammation and fibrosis of keloid, 50 patients with keloid and 50 healthy subjects were enrolled, We examined the serum and mRNA expression levels of adiponectin, TGF-β1, CTGF, IL-6 and TNF-α in normal skin tissues and keloid tissues by ELISA and qPCR, respectively. Correlation analysis between serum concentration of adiponectin with Vancouver Scar Scale (VSS) scores and the age of patients with keloid was evaluated, and the adiponectin concentrations in patients with keloid between different genders were measured. We further examined the effects of adiponectin on TGF-β1 mediated expression of collagen I, FN and MMP-1 in normal fibroblasts (NFs) and keloid fibroblasts (KFs).

RESULTS

We discovered that lower serum concentration and mRNA expression of adiponectin, but higher TGF-β1, CTGF, IL-6 and TNF-α levels were measured in patients with keloid compared with those in normal controls. Furthermore, there was a strong inverse correlation between the serum adiponectin levels and VSS scores in patients with keloid, but not in ages, and there was no statistically difference between different genders. Moreover, adiponectin attenuated TGF-β1 mediated expression of collagen I and FN, and upregulated the expression level of MMP-1 in KFs, but not in NFs. In addition, the inhibitory effect of adiponectin on TGF-β1 was attenuated by AMPK inhibitor Compound C, but not PI3K/Akt inhibitor LY294002.

DISCUSSION

Adiponectin may exert an anti-inflammation and anti-fibrosis role in the development of keloid. One of the underlying mechanisms may be the activation of the AMPK signaling pathway.

The Roles of Inflammation in Keloid and Hypertrophic Scars

The underlying mechanisms of wound healing are complex but inflammation is one of the determining factors. Besides its traditional role in combating against infection upon injury, the characteristics and magnitude of inflammation have dramatic impacts on the pathogenesis of scar. Keloids and hypertrophic scars are pathological scars that result from aberrant wound healing. They are characterized by continuous local inflammation and excessive collagen deposition. In this review, we aim at discussing how dysregulated inflammation contributes to the pathogenesis of scar formation. Immune cells, soluble inflammatory mediators, and the related intracellular signal transduction pathways are our three subtopics encompassing the events occurring in inflammation associated with scar formation. In the end, we enumerate the current and potential medicines and therapeutics for suppressing inflammation and limiting progression to scar. Understanding the initiation, progression, and resolution of inflammation will provide insights into the mechanisms of scar formation and is useful for developing effective treatments.

Long-term Treatment with Anti-platelet Agents for Collagen-induced Arthritis Improves Radiological Findings

Objectives

The objectives of this study were to evaluate the long-term effect of anti-platelet treatment on the radiological progression of collagen-induced arthritis in rats.

Methods

Female Lewis rats with collagen-induced arthritis were divided into three experimental groups: saline, aspirin monotherapy (n = 12), and aspirin–clopidogrel dual therapy (n = 12). Drugs were administered daily and continued up to 70 days after the induction of arthritis. The clinical arthritis index (weight, morphology score, and paw thickness) and radiological scores were evaluated.

Results

The clinical arthritis index peaked on day 20, while the radiological scores peaked on day 35. No intergroup difference was observed in the clinical arthritis index throughout the experiment. The aspirin–clopidogrel dual therapy group had a significantly higher mean radiological score than the other groups (p = 0.045) on day 35. Further treatments resulted in significantly improved radiological findings in the aspirin monotherapy and aspirin–clopidogrel dual therapy groups on day 70 but no significant improvement in the saline group.

Conclusion

Anti-platelet agent treatment improved radiological findings on day 70. These observations emphasize the importance of a future long-term study of the effects of anti-platelet agent treatment on arthritis.

Aspirin: a review of its neurobiological properties and therapeutic potential for mental illness

There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory 'braking signals', including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor-α and interleukin (IL)--6, but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.

Selective histonedeacetylase inhibitor M344 intervenes in HIV-1 latency through increasing histone acetylation and activation of NF-kappaB

BACKGROUND

Histone deacetylase (HDAC) inhibitors present an exciting new approach to activate HIV production from latently infected cells to potentially enhance elimination of these cells and achieve a cure. M344, a novel HDAC inhibitor, shows robust activity in a variety of cancer cells and relatively low toxicity compared to trichostatin A (TSA). However, little is known about the effects and action mechanism of M344 in inducing HIV expression in latently infected cells.

METHODOLOGY/PRINCIPAL FINDINGS

Using the Jurkat T cell model of HIV latency, we demonstrate that M344 effectively reactivates HIV-1 gene expression in latently infected cells. Moreover, M344-mediated activation of the latent HIV LTR can be strongly inhibited by a NF-κB inhibitor aspirin. We further show that M344 acts by increasing the acetylation of histone H3 and histone H4 at the nucleosome 1 (nuc-1) site of the HIV-1 long terminal repeat (LTR) and by inducing NF-κB p65 nuclear translocation and direct RelA DNA binding at the nuc-1 region of the HIV-1 LTR. We also found that M344 synergized with prostratin to activate the HIV-1 LTR promoter in latently infected cells.

CONCLUSIONS/SIGNIFICANCE

These results suggest the potential of M344 in anti-latency therapies and an important role for histone modifications and NF-κB transcription factors in regulating HIV-1 LTR gene expression.

β-1,4-Galactosyltransferase I involved in Schwann cells proliferation and apoptosis induced by tumor necrosis factor-alpha via the activation of MAP kinases signal pathways

β-1,4-galactosyltransferase-I (β-1,4-GalT-I) plays a critical role in the initiation and maintenance of peripheral nervous system inflammatory reaction. However, the exact function of β-1,4-GalT-I in the regulation of SCs proliferation and apoptosis remains unclear. In this study, we found that low concentration of tumor necrosis factor-alpha (TNF-α) induced SCs proliferation, while high concentration of TNF-α induced SCs apoptosis. Meanwhile, the expressions of β-1,4-GalT-I, TNFR1, and TNFR2 were changed following. When β-1,4-GalT I overexpression, low concentration of TNF-α-induced SCs proliferation was partially repressed. Concurrently, the activity of ERK1/2 was decreased. While knocking down β-1,4-GalT I expression, high concentration of TNF-α-induced SCs apoptosis was partially rescued. Consistent with this, the activity of P38 and JNK were decreased. We also found anti-TNFR2 antibody suppressed low concentration of TNF-α-induced SCs proliferation, while anti-TNFR1 antibody inhibited high concentration of TNF-α-induced SCs apoptosis. Thus, present data show that β-1,4-GalT I may play an important role in SCs proliferation and apoptosis induced by TNF-α via different signal pathways and TNFR.

β-1,4-galactosyltransferase I promotes tumor necrosis factor-α autocrine via the activation of MAP kinase signal pathways in Schwann cells

Recent studies have demonstrated that aberrant galactosylation is associated with some inflammation diseases. β-1,4-Galactosyltransferase-I (β-1,4-GalT I), which transferred galactose to the terminal N-acetylglucosamine of N- and O-linked glycans in a β-1,4-linkage, was considered to be the major galactosyltransferase among the seven members of the subfamily responsible for β4 galactosylation. To elucidate the expression and possible function of β-1,4-GalT I in the peripheral nervous system (PNS) inflammatory diseases, we performed a tumor necrosis factor-alpha (TNF-α) autocrine inflammatory model in Schwann cells (SCs). In this study, we found that silencing of β-1,4-GalT I suppressed TNF-α autocrine, while overexpression of β-1,4-GalT I promoted TNF-α autocrine in TNF-α-treated SCs. Meanwhile, anti-TNFR1 antibody suppressed the expression of β-1,4-GalT I, and TNF-α autocrine. β-1,4-GalT I conferred its effect by promoting ERK, JNK, and P38 MAP kinase signal pathways activation in TNF-α-induced SCs. Thus, the present data shows that during SCs activation, β-1,4-GalT I may play an important role in the release of inflammatory mediators.

SSeCKS promotes tumor necrosis factor-alpha autocrine via activating p38 and JNK pathways in Schwann cells

Tumor necrosis factor-alpha (TNF-alpha) derived from activated Schwann cells (SCs) plays a critical role as an inflammatory mediator in the peripheral nervous system disease. TNF-alpha could act as an autocrine mediator in SC activation. In this study, we found knockdown Src-suppressed protein kinase C substrate (SSeCKS) expression suppressed TNF-alpha production induced by TNF-alpha, overexpression of SSeCKS could promoted TNF-alpha autocrine in SCs. Such effects might be resulted in SSeCKS promoted p38 and JNK activation in SCs treated by TNF-alpha. Thus present data show that while SCs activation, SSeCKS may plays an important role in the release of inflammatory mediators.