Interleukin-1-receptor-associated kinase 2 (IRAK2)-mediated interleukin-1-dependent nuclear factor kappaB transactivation in Saos2 cells requires the Akt/protein kinase B kinase

Exploring novel protein biomarkers for early-stage diagnosis and prognosis of T-acute lymphoblastic leukemia (T-ALL)

BACKGROUND

Efficient classification of T-acute lymphoblastic leukemia (T-ALL) involves considering various factors, such as age, white blood cell count, and chromosomal alterations. However, studying protein markers are crucial to improving T-ALL patients' diagnosis and treatment. A study analyzing the expression of proteomes was conducted to identify promising early-stage biomarkers for T-ALL patients METHODS: Label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze the blood proteins of both patients and healthy individuals to identify new biomarkers for T-ALL. The findings were validated by RT-PCR, ELISA and computational analysis RESULTS: The study identified 1467 proteins in the blood, of which nine were upregulated and 35 were downregulated by more than 2-fold. T-ALL patients showed a significant increase in specific disease-related proteins, such as eleven-nineteen lysine-rich leukemia protein, triggering receptor expressed on myeloid cells 1, cisplatin resistance-associated-overexpressed protein, X-ray radiation resistance-associated protein 1, tumor necrosis factor receptor superfamily member 10D, protein S100-A8, and copine-4, by more than 3-fold CONCLUSION: The findings of this study provide a valuable protein map of leukemic cells and identify potential biomarkers for leukemic aggressiveness. However, further studies using larger T-ALL patient samples must confirm these preliminary results.

Toxic effects of ammonia on the intestine of the Asian clam (Corbicula fluminea)

Intestines contain a large number of microorganisms that collectively play a vital role in regulating physiological and biochemical processes, including digestion, water balance, and immune function. In this study, we explored the effects of ammonia stress on intestinal inflammation, the antioxidant system, and the microbiome of the Asian clam (Corbicula fluminea). Exposure to varying ammonia concentrations (10 and 25 mg N/L) and exposure times (7 and 14 days) resulted in damage to C. fluminea intestinal tissue, according to histological analysis. Furthermore, intestinal inflammatory responses and damage to the antioxidant system were revealed through qPCR, ELISA, and biochemical analysis experiments. Inflammatory responses were more severe in the treatment group exposed to a lower concentration of ammonia. High-throughput 16S rDNA sequencing showed that ammonia stress under different conditions altered intestinal bacterial diversity and microbial community composition, particularly impacting the dominant phylum Proteobacteria and genus Aeromonas. These results indicate that ammonia stress can activate intestinal inflammatory reactions, damage the intestinal antioxidant system, and alter intestinal microbial composition, thereby impeding intestinal physiological function and seriously threatening the health of C. fluminea.

Shear stress induces human aortic endothelial cell apoptosis via interleukin‑1 receptor‑associated kinase 2‑induced endoplasmic reticulum stress

Atherosclerosis is characterized by localized lesions distributed in the arterial tree due to the shear stress produced by blood flow. Endothelial cells are directly affected by alterations in blood flow. Dysfunction and injury to endothelial cells has been hypothesized to initiate the pathological processes of atherosclerosis. The present study aimed to investigate the mechanism of shear stress-induced endothelial cellular apoptosis. Shear stress was generated using an artificial device to mimic the impact of disturbed blood flow on cultured human aortic endothelial cells (HAECs). Cellular apoptosis was assessed using a terminal deoxynucleotidyl transferase dUTP nick end labeling assay; an ELISA assay was used to detect the produced interleukin (IL)-1β; specific small interfering (si)RNA was used to knockdown the expression of interleukin-1 receptor-associated kinase 2 (IRAK2) in HAECs and the expression levels of 78 kDa glucose-regulated protein, DNA damage-inducible transcript 3 protein (CHOP), IRAK2 and IL-1β were evaluated using western blotting. The results of the present study demonstrated that artificial shear stress induced endoplasmic reticulum (ER) stress, IL-1β production and apoptosis in HAECs in a time-dependent manner. The inhibition of ER stress, and treatment with interleukin-1 receptor antagonist protein and siRNA against IRAK2 attenuated shear stress-induced CHOP signaling-mediated cellular apoptosis. Therefore, overproduction of IL-1β exacerbated shear stress-induced ER stress-mediated apoptosis via the IRAK2/CHOP signaling pathway in endothelial cells.

Circulating interleukin-1β promotes endoplasmic reticulum stress-induced myocytes apoptosis in diabetic cardiomyopathy via interleukin-1 receptor-associated kinase-2

Aim

IL-1β was considered as an important inflammatory cytokine in diabetic cardiovascular complications. DCM is one of the major manifestations of diabetic cardiovascular complications whose specific mechanisms are still unclear. In this study, we investigated the role of IL-1β in myocytes apoptosis in DCM.

Methods

In the in vitro study, high- glucose medium and/or IL-1β were used to incubate the isolated primary myocytes. siRNA was used to knockdown the irak2 gene expression. Apoptosis was evaluated by Hoechst and TUNEL staining. In the in vivo study, DCM in rats was induced by STZ injection and confirmed by cardiac hemodynamic determinations. The IL-1 receptor antagonist, IL-1Ra was also used to treat DCM rats. Myocardial apoptosis was assessed by TUNEL assay. In both in vitro and in vivo studies, expression levels of GRP-78, IRAK-2 and CHOP were analyzed by Western Blotting. ELISA was employed to exam the IL-1β content in serum and cell supernatants.

Results

Myocytes were not identified as the source of IL-1β secretion under high- glucose incubation. High glucose incubation and/or IL-1β incubation elevated ER- stress mediated myocytes apoptosis which was attenuated by irak2 silencing. Dramatically increased circulating and myocardial IL-1β levels were found in DCM rats which stimulated activation of ER stress and lead to elevated myocytes apoptosis. The administration of IL-1Ra, however, attenuated IRAK2/CHOP induced apoptosis without affecting fasting blood glucose concentration.

Conclusions

Elevated circulating IL-1β contributed to promote ER stress- induced myocytes apoptosis by affecting IRAK-2/CHOP pathway in DCM.

Lamin A Ser404 is a nuclear target of Akt phosphorylation in C2C12 cells

Akt/PKB is a central activator of multiple signaling pathways coupled with a large number of stimuli. Although both localization and activity of Akt in the nuclear compartment are well-documented, most Akt substrates identified so far are located in the cytoplasm, while nuclear substrates have remained elusive. A proteomic-based search for nuclear substrates of Akt was undertaken, exploiting 2D-electrophoresis/MS in combination with an anti-Akt phosphosubstrate antibody. This analysis indicated lamin A/C as a putative substrate of Akt in C2C12 cells. In vitro phosphorylation of endogenous lamin A/C by recombinant Akt further validated this result. Moreover, by phosphopeptide analysis and point mutation, we established that lamin A/C is phosphorylated by Akt at Ser404, in an evolutionary conserved Akt motif. To delve deeper into this, we raised an antibody against the lamin A Ser404 phosphopeptide which allowed us to determine that phosphorylation of lamin A Ser404 is triggered by the well-known Akt activator insulin, and is therefore to be regarded as a physiological response. Remarkably, expression of S404A lamin A in primary cells from healthy tissue caused the nuclear abnormalities that are a hallmark of Emery-Dreifuss muscular dystrophy (EDMD) cells. Indeed, it is known that mutations at several sites in lamin A/C cause autosomal dominant EDMD. Very importantly, we show here that Akt failed to phosphorylate lamin A/C in primary cells from an EDMD-2 patient with lamin A/C mutated in the Akt consensus motif. Together, our data demonstrate that lamin A/C is a novel signaling target of Akt, and implicate Akt phosphorylation of lamin A/C in the correct function of the nuclear lamina.

MyD88 functions as a negative regulator of TLR3/TRIF-induced corneal inflammation by inhibiting activation of c-Jun N-terminal kinase

The adaptor molecule MyD88 is necessary for responses to all Toll-like receptors except TLR3 and a subset of TLR4 signaling events, which are mediated by the adaptor molecule TRIF. To determine the role of TRIF in host inflammatory responses, corneal epithelium of C57BL/6, TLR3(-/-), TRIF(-/-), and MyD88(-/-) mice was abraded and stimulated with the synthetic TLR3 ligand poly(I:C). We found that poly(I:C) induced a pronounced cellular infiltration into the corneal stroma, which was TLR3- and TRIF-dependent. Unexpectedly, the inflammatory response was exacerbated in MyD88(-/-) mice, with enhanced neutrophil and F4/80(+) cell infiltration into the corneal stroma and elevated corneal haze, which is an indicator of loss of corneal transparency. To determine whether MyD88-dependent inhibition of TLR3/TRIF responses is a general phenomenon, we examined cytokine production by MyD88(-/-) bone marrow-derived macrophages; however, no significant difference was observed between MyD88(+/+) or MyD88(-/-) macrophages. In contrast, human corneal epithelial cells (HCECs) transfected with MyD88 small interfering RNA had significantly increased (2.5-fold) CCL5/RANTES production compared with control HCECs, demonstrating a negative regulatory role for MyD88 in TLR3/TRIF responses in these cells. Finally, knockdown of MyD88 in HCECs resulted in increased phosphorylation of c-Jun N-terminal kinase (JNK), but not p38, IRF-3, or NF-kappaB. Consistent with this finding, the JNK inhibitor SP600125, but not p38 inhibitor SB203580, ablated this response. Taken together, these findings demonstrate a novel JNK-dependent inhibitory role for MyD88 in the TLR3/TRIF activation pathway.

Nurr1 dependent regulation of pro-inflammatory mediators in immortalised synovial fibroblasts

Background

Nurr1 is an orphan member of the nuclear receptor superfamily; these orphan receptors are a group for which a ligand has yet to be identified. Nurr1 has been shown to regulate the expression of a small number of genes as a monomeric, constitutively active receptor. These Nurr1 regulated genes are primarily associated with dopamine cell maturation and survival. However, previous reports have shown an increased expression of Nurr1 in the synovium of patients with rheumatoid arthritis (RA) suggesting a pro-inflammatory role for Nurr1 in RA. In this study we investigate the potential pro-inflammatory role of Nurr1 by monitoring Nurr1 dependent gene expression in an immortalised synoviocyte cell line, K4IM.

Methods

We overexpressed the wild type and a dominant negative form of the orphan nuclear receptor Nurr1, in a model synoviocyte cell line. Using the Affymetrix HG-U133 Genechips we demonstrate the effects on the transcriptome by the receptor. Further evidence of gene expression change was demonstrated using quantitative RT-PCR and ELISA analysis.

Results

We show that Nurr1 regulates transcription of a small number of genes for pro-inflammatory modulators of which the most significant is interleukin-8 (IL-8). We also demonstrate increased synthesis and secretion of IL-8 further supporting a role for Nurr1 in inflammatory signalling pathways.

Conclusion

Using microarray analysis we show that elevated levels of Nurr1 leads to increased gene expression of pro-inflammatory genes: IL-8, Amphiregulin and Kit ligand in a model cell line. This data provides further evidence for an additional role for Nurr1 in inflammation and may play a role in the pathogenesis of rheumatoid arthritis.