TRAIL mRNA expression in peripheral blood mononuclear cells of Egyptian SLE patients

Reduced expressions of apoptosis-related proteins TRAIL, Bcl-2, and TNFR1 in NK cells of juvenile-onset systemic lupus erythematosus patients: relations with disease activity, nephritis, and neuropsychiatric involvement

Background

Lupus pathogenesis is mainly ascribed to increased production and/or impaired clearance of dead cell debris. Although self-reactive T and B lymphocytes are critically linked to lupus development, neutrophils, monocytes, and natural killer (NK) cells have also been implicated. This study assessed apoptosis-related protein expressions in NK cells of patients with juvenile-onset systemic lupus erythematosus (jSLE) and relations to disease activity parameters, nephritis, and neuropsychiatric involvement.

Methods

Thirty-six patients with jSLE, 13 juvenile dermatomyositis (JDM) inflammatory controls, and nine healthy controls had Fas, FasL, TRAIL, TNFR1, Bcl-2, Bax, Bim, and caspase-3 expressions in NK cells (CD3-CD16+CD56+) simultaneously determined by flow cytometry. Disease activity parameters included Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score, erythrocyte sedimentation rate, C-reactive protein level, anti-double strain DNA antibody level, complement fractions C3 and C4 levels.

Results

Patients with jSLE had a profile of significantly reduced expression of TRAIL, Bcl-2, and TNFR1 proteins in NK cells when compared to healthy controls. Similar profile was observed in patients with jSLE with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. Patients with jSLE with positive anti-dsDNA also had reduced expression of Bax in NK cells when compared healthy controls and to those with negative anti-dsDNA. Yet, patients with jSLE with negative anti-dsDNA had reduced mean fluorescence intensity (MFI) of Bim in NK cells compared to healthy controls. Patients with jSLE with nephritis also had reduced MFI of Fas in NK cells when compared to those without nephritis. In addition, in patients with jSLE, the proportion of FasL-expressing NK cells directly correlated with the SLEDAI-2K score (rs = 0.6, p = 0.002) and inversely correlated with the C3 levels (rs = -0.5, p = 0.007). Moreover, patients with jSLE had increased NK cell percentage and caspase-3 protein expression in NK cells when compared to JDM controls.

Conclusion

This study extends to NK cells an altered profile of TRAIL, Bcl-2, TNFR1, Fas, FasL, Bax, Bim, and caspase-3 proteins in patients with jSLE, particularly in those with active disease, positive anti-dsDNA, nephritis, and without neuropsychiatric involvement. This change in apoptosis-related protein expressions may contribute to the defective functions of NK cells and, consequently, to lupus development. The full clarification of the role of NK cells in jSLE pathogenesis may pave the way for new therapies like those of NK cell-based.

Understanding the role of key amino acids in regulation of proline dehydrogenase/proline oxidase (prodh/pox)-dependent apoptosis/autophagy as an approach to targeted cancer therapy

In stress conditions, as neoplastic transformation, amino acids serve not only as nutrients to maintain the cell survival but also as mediators of several regulatory pathways which are involved in apoptosis and autophagy. Especially, under glucose deprivation, in order to maintain the cell survival, proline and glutamine together with other glutamine-derived products such as glutamate, alpha-ketoglutarate, and ornithine serve as alternative sources of energy. They are substrates for production of pyrroline-5-carboxylate which is the product of conversion of proline by proline dehydrogenase/ proline oxidase (PRODH/POX) to produce ATP for protective autophagy or reactive oxygen species for apoptosis. Interconversion of proline, ornithine, and glutamate may therefore regulate PRODH/POX-dependent apoptosis/autophagy. The key amino acid is proline, circulating between mitochondria and cytoplasm in the proline cycle. This shuttle is known as proline cycle. It is coupled to pentose phosphate pathway producing nucleotides for DNA biosynthesis. PRODH/POX is also linked to p53 and AMP-activated protein kinase (AMPK)-dependent pathways. Proline availability for PRODH/POX-dependent apoptosis/autophagy is regulated at the level of collagen biosynthesis (proline utilizing process) and prolidase activity (proline supporting process). In this review, we suggest that amino acid metabolism linking TCA and Urea cycles affect PRODH/POX-dependent apoptosis/autophagy and the knowledge might be useful to targeted cancer therapy.

Machine learning applied to whole-blood RNA-sequencing data uncovers distinct subsets of patients with systemic lupus erythematosus

Objectives

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease that is difficult to treat. There is currently no optimal stratification of patients with SLE, and thus, responses to available treatments are unpredictable. Here, we developed a new stratification scheme for patients with SLE, based on the computational analysis of patients’ whole‐blood transcriptomes.

Methods

We applied machine learning approaches to RNA‐sequencing (RNA‐seq) data sets to stratify patients with SLE into four distinct clusters based on their gene expression profiles. A meta‐analysis on three recently published whole‐blood RNA‐seq data sets was carried out, and an additional similar data set of 30 patients with SLE and 29 healthy donors was incorporated in this study; a total of 161 patients with SLE and 57 healthy donors were analysed.

Results

Examination of SLE clusters, as opposed to unstratified SLE patients, revealed underappreciated differences in the pattern of expression of disease‐related genes relative to clinical presentation. Moreover, gene signatures correlated with flare activity were successfully identified.

Conclusion

Given that SLE disease heterogeneity is a key challenge hindering the design of optimal clinical trials and the adequate management of patients, our approach opens a new possible avenue addressing this limitation via a greater understanding of SLE heterogeneity in humans. Stratification of patients based on gene expression signatures may be a valuable strategy allowing the identification of separate molecular mechanisms underpinning disease in SLE. Further, this approach may have a use in understanding the variability in responsiveness to therapeutics, thereby improving the design of clinical trials and advancing personalised therapy.

Tumour necrosis factor-related apoptosis-inducing ligand expression in patients with diabetic nephropathy

Objective:

The objective of this study was to evaluate the expression profile of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) in patients with diabetic nephropathy (DN).

Methods:

A total of 126 Chinese subjects were enrolled in this study, including 42 patients with diabetes mellitus (DM), 42 patients with DN and 42 healthy controls. Real-time polymerase chain reaction was performed to analyze levels of TRAIL mRNA in peripheral blood mononuclear cells (PBMCs). Serum levels of soluble TRAIL (sTRAIL) and various cytokines were detected with a commercially available enzyme-linked immunosorbent assay kit.

Results:

Compared with the control group, the levels of TRAIL mRNA in PBMCs and sTRAIL in sera were both significantly decreased in the DM and DN patients (P < 0.05). Conversely, levels of interleukin (IL)-1, IL-6, tumour necrosis factor-α and monocyte chemotactic protein-1 were higher in the DN group than in the control group. Serum levels of TRAIL positively correlated with TRAIL mRNA levels in all of the subjects examined (P < 0.05).

Conclusions:

These results provide support and a theoretical basis for further research of TRAIL in regard to the pathogenesis of DN.

Analysis of the regulatory function of natural killer cells from patients with systemic lupus erythematosus

Natural killer (NK) cells participate in the regulation of the immune response. However, the immunomodulatory function of NK cells in systemic lupus erythematosus (SLE) is not well understood. The aim of this study was to evaluate the regulatory function of NK cells in SLE patients and to identify the NK cells involved in the pathogenesis of this complex disease. We analysed the expression of NK receptors and co-stimulatory molecules in peripheral NK cells (CD3^- CD56⁺ ) from SLE patients, as well as the numbers of human leucocyte antigen D-related (HLA-DR)/CD11c⁺ NK cells. In addition, NK cell regulatory function was assessed by the detection of NK cell-mediated dendritic cell (DC) lysis. We found that SLE patients showed increased numbers of immunoglobulin-like transcript 2 (ILT2)⁺ , CD86⁺ and CD134⁺ NK cells. Furthermore, NK cells from SLE patients induced higher levels of DC lysis. We were able to identify a new subset of NK cells co-expressing CD11c and HLA-DR. These atypical NK cells were increased in SLE patients when compared with controls. We have identified an expanded new subset of NK cells in SLE patients. This is the first study, to our knowledge, which demonstrates that NK cells in SLE patients have an altered phenotype with a high expression of receptors characteristic of dendritic cells. Our results suggest that the impairment in the regulatory function of NK cells, together with the increased number of DC-like NK cells, could play an important role in the development of SLE and highlight the importance of NK cells as a future therapeutic target.

Neuroprotective effect of (-)-epigallocatechin-3-gallate on autoimmune thyroiditis in a rat model by an anti-inflammation effect, anti-apoptosis and inhibition of TRAIL signaling pathway

(-)-Epigallocatechin-3-gallate (EGCG) is a polyphenol monomer compound extracted and separated from green tea, and is a key catechin in green tea. Recent research has identified that EGCG is equipped with important biological activities, including antitumor, antioxidant, anti-inflammation, blood fat reduction and radiation protection abilities. In the current study, it was investigated whether EGCG exerts a neuroprotective effect on AIT and examined the possible underlying mechanism. The present study sought to establish an experimental autoimmune thyroiditis (AIT) rat model and to investigate the neuroprotective effect of EGCG in this model. EGCG was demonstrated to inhibit urinary iodine values and thyroid pathological features in AIT model rats. Treatment with EGCG significantly reduced interleukin-1β, interferon-γ (INF-γ) and tumor necrosis factor-α (TNF-α) levels in the AIT rats through suppression of nuclear factor-κB (NF-κB) pathway. In addition, pretreatment with EGCG significantly increased B-cell lymphoma-2 protein expression, and suppressed caspase-3 activity and TNF-α-related apoptosis-inducing ligand (TRAIL) protein expression levels in the AIT model rats. In conclusion, these results suggested that the neuroprotective effect of EGCG protects against AIT through its anti-inflammatory ability, anti-apoptosis and TRAIL signaling pathway in model rats, and it may be used as a therapeutic agent against AIT caused by inflammation.

Influenza A (H1N1) virus infection triggers severe pulmonary inflammation in lupus-prone mice following viral clearance

Each year, up to one fifth of the United States population is infected with influenza virus. Although mortality rates are low, hundreds of thousands are hospitalized each year in the United States. Specific high risk groups, such as those with suppressed or dysregulated immune systems, are at greater danger for influenza complications. Respiratory infections are a common cause of hospitalizations and early mortality in patients with systemic lupus erythematosus (SLE); however, whether this increased infection risk is a consequence of the underlying dysregulated immune background and/or immunosuppressing drugs is unknown. To evaluate the influenza immune response in the context of lupus, as well as assess the effect of infection on autoimmune disease in a controlled setting, we infected lupus-prone MRL/MpJ-Fas(lpr) mice with influenza virus A PR/8/34 H1N1. Interestingly, we found that Fas(lpr) mice generated more influenza A virus specific T cells with less neutrophil accumulation in the lung during acute infection. Moreover, Fas(lpr) mice produced fewer flu-specific IgG and IgM antibodies, but effectively cleared the virus. Further, increased extrinsic apoptosis during influenza infection led to a delay in autoimmune disease pathology with decreased severity of splenomegaly and kidney disease. Following primary influenza A infection, Fas(lpr) mice had severe complications during the contraction and resolution phase with widespread severe pulmonary inflammation. Our findings suggest that influenza infection may not exacerbate autoimmune pathology in mice during acute infection as a direct result of virus induced apoptosis. Additionally, autoimmunity drives an enhanced antigen-specific T cell response to clear the virus, but persisting pulmonary inflammation following viral clearance may cause complications in this lupus animal model.

Current and emerging biomarkers of cell death in human disease

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.