Role of tumor necrosis factor alpha-induced protein 1 in paclitaxel resistance

Knocking down TNFAIP1 alleviates inflammation and oxidative stress in pediatric pneumonia through PI3K/Akt/Nrf2 pathway

BACKGROUND

Pneumonia is an acute respiratory infection with increasing global incidences. Children are more susceptible to pneumonia than adults, and its incidences grow extremely high during peak seasons. Thus, it is necessary to investigate the pathogenesis and molecular mechanism of childhood pneumonia.

METHODS

This study examined the role of tumor necrosis factor alpha-inducible protein 1 (TNFAIP1) in lipopolysaccharide (LPS)-induced pneumonia mice. After LPS exposure, lung function, TNFAIP1 activation, infarction volume, oxidative stress, lung tissue apoptosis ratio, and inflammatory response were assessed by immunohistochemistry staining, hematoxylin and eosin staning, Western blot analysis, terminal deoxynucleotidyl transferase dUTP nick end labelling assay, and enzyme-linked-immunosorbent serologic assay, respectively. The mechanism of TNFAIP1 regulating phosphoinositide 3-kinases (PI3K)-protein kinase B (Akt)-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway was analyzed by Western blot analysis.

RESULTS

TNFAIP1 expression was enhanced in the LPS-induced pneumonia mice but was negatively correlated with the LPS-induced lung injury. Silencing TNFAIP1 alleviated inflammatory response, production of reactive oxygen species (ROS), and cellular apoptosis in LPS-induced pneumonia. Moreover, PI3K/Akt/Nrf2 signaling pathways were predominantly involved in the TNFAIP1-mediated lung injury, which also played a role in the process of LPS-induced pneumonia.

CONCLUSION

This study suggested that TNFAIP1 acted as a negative regulator of acute pneumonia by attenuating inflammatory response, production of ROS, and cellular apoptosis via PI3K/Akt/Nrf2 pathway. The findings suggested that TNFAIP1 is a potential candidate for pneumonia therapy.

Inhibition of TNFAIP1 ameliorates the oxidative stress and inflammatory injury in myocardial ischemia/reperfusion injury through modulation of Akt/GSK-3β/Nrf2 pathway

Tumor necrosis factor α-induced protein 1 (TNFAIP1) has been documented as a vital regulator of apoptosis and oxidative stress under various pathological conditions. However, whether TNFAIP1 plays a role in myocardial ischemia/reperfusion (I/R) injury has not been well investigated. This work aimed to evaluate the possible role of TNFAIP1 in mediating myocardial I/R injury. Firstly, we demonstrated that TNFAIP1 expression was dramatically increased in rat cardiomyocytes following hypoxia/reoxygenation (H/R) in vitro, and in rat myocardial tissues following I/R treatment in vivo. Silencing of TNFAIP1 alleviated H/R-induced apoptosis, oxidative stress and inflammatory response in rat cardiomyocytes in vitro. Moreover, knockdown of TNFAIP1 ameliorated I/R-induced myocardial injury, infarction size, cardiac apoptosis, oxidative stress and inflammatory response in vivo. Further investigation elucidated that knockdown of TNFAIP1 enhanced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling associated with modulation of the Akt/glycogen synthase kinase-3β (GSK-3β) pathway in vitro and in vivo. Inhibition of Akt markedly abrogated TNFAIP1-knockdown-mediated Nrf2 activation in cardiomyocytes following H/R injury. In addition, suppression of Nrf2 significantly diminished TNFAIP1-knockdown-induced cardioprotective effects in H/R-exposed cardiomyocytes. In summary, this work elucidates that inhibition of TNFAIP1 ameliorates myocardial I/R injury by potentiating Nrf2 signaling via the modulation of the Akt/GSK-3β pathway. Our study highlights a vital role of the TNFAIP1/Akt/GSK-3β/Nrf2 pathway in mediating myocardial I/R injury and suggests TNFAIP1 as an attractive target for treatment of this disease.

The emerging role of the KCTD proteins in cancer

The human family of Potassium (K+) Channel Tetramerization Domain (KCTD) proteins counts 25 members, and a significant number of them are still only partially characterized. While some of the KCTDs have been linked to neurological disorders or obesity, a growing tally of KCTDs are being associated with cancer hallmarks or involved in the modulation of specific oncogenic pathways. Indeed, the potential relevance of the variegate KCTD family in cancer warrants an updated picture of the current knowledge and highlights the need for further research on KCTD members as either putative therapeutic targets, or diagnostic/prognostic markers. Homology between family members, capability to participate in ubiquitination and degradation of different protein targets, ability to heterodimerize between members, role played in the main signalling pathways involved in development and cancer, are all factors that need to be considered in the search for new key players in tumorigenesis. In this review we summarize the recent published evidence on KCTD members' involvement in cancer. Furthermore, by integrating this information with data extrapolated from public databases that suggest new potential associations with cancers, we hypothesize that the number of KCTD family members involved in tumorigenesis (either as positive or negative modulator) may be bigger than so far demonstrated. Video abstract.

The role of TNF-α induced protein 1 in the activation of pro-apoptotic proteins

It is known that Porphyromonas gingivalis/lipopolysaccharide (P. gingivalis/LPS) induces inflammatory diseases via TNF-α-mediated transcription factors. Our recent data shows that TNFAIP1 (TNF-α induced protein 1) is related to TNF-α. However, little is known regarding how TNFAIP1 is involved in the TNF-α-dependent pathway. We therefore focused on the biological function of TNFAIP1 and examined how TNFAIP1 mediates TNF-α and other genes. We found that TNF-α was upregulated and peaks before the upregulation of apoptotic genes such as Bad, Bcl-x, Caspase 3, Catalase, Claspin, Cytochromic, Ho-1/HMOX1/HSP32, or MCI-1 in our time course with TNFAIP1-treated cells. Our findings here may serve as the foundation for future studies linking regulation of TNFAIP1 and intervention of inflammatory disease.

Cullin3-TNFAIP1 E3 Ligase Controls Inflammatory Response in Hepatocellular Carcinoma Cells via Ubiquitination of RhoB

Rho family GTPase RhoB is the critical signaling component controlling the inflammatory response elicited by pro-inflammatory cytokines. However, the underlying mechanisms of RhoB degradation in inflammatory response remain unclear. In this study, for the first time, we identified that TNFAIP1, an adaptor protein of Cullin3 E3 ubiquitin ligases, coordinated with Cullin3 to mediate RhoB degradation through ubiquitin proteasome system. In addition, we demonstrated that downregulation of TNFAIP1 induced the expression of pro-inflammatory cytokines IL-6 and IL-8 in TNFα-stimulated hepatocellular carcinoma cells through the activation of p38/JNK MAPK pathway via blocking RhoB degradation. Our findings revealed a novel mechanism of RhoB degradation and provided a potential strategy for anti-inflammatory intervention of tumors by targeting TNFAIP1-RhoB axis.

Circ0001320 inhibits lung cancer cell growth and invasion by regulating TNFAIP1 and TPM1 expression through sponging miR-558

Lung cancer is the most affected malignant tumor in the world, and its specific pathogenesis is still unclear. It has been confirmed that circ0001320 is down-regulated in lung cancer, but its mechanism has not been reported. Further study found that circ0001320 was down-regulated in lung cancer cells, localized in the cytoplasm, and had multiple miR-558 binding sites. Dual-luciferase reporter gene assay, RNA-pull-down, and immunoprecipitation experiments all confirmed that circ0001320 directly bound to miR-558, and then inhibit the expression of miR-558. MiR-558 was up-regulated in lung cancer cells, and bound the downstream target genes TNFAIP1 and TPM1 to inhibit their expression. Western blot showed that circ0001320 significantly up-regulated the protein levels of TNFAIP1 and TPM1, while miR-558 blocked this effect of circ0001320. Circ0001320, TNFAIP1, and TPM1 all inhibited the proliferation and invasion of lung cancer cells and promoted apoptosis, while miR-558 had the opposite effects. After transfection with circ0001320 overexpression vector, miR-558 up-regulation or down-regulation of TNFAIP1, or TPM1 expression significantly reversed the inhibition of cell growth and invasion by circ0001320. Similarly, the expression of TNFAIP1 or TPM1 was down-regulated, while miR-558 expression was inhibited, and the levels of cell proliferation, apoptosis, and invasion did not change significantly. Therefore, these fully show that circ0001320 inhibits the growth and invasion of lung cancer cells through miR-558/TNFAIP1 and TPM1 pathways, which may be closely related markers and therapeutic targets of lung cancer.

The CRL3BTBD9 E3 ubiquitin ligase complex targets TNFAIP1 for degradation to suppress cancer cell migration

Tumor necrosis factor alpha-induced protein 1 (TNFAIP1) modulates a plethora of important biological processes, including tumorigenesis and cancer cell migration. However, the regulatory mechanism of TNFAIP1 degradation remains largely elusive. In the present study, with a label-free quantitative proteomic approach, TNFAIP1 was identified as a novel ubiquitin target of the Cullin-RING E3 ubiquitin ligase (CRL) complex. More importantly, Cul3-ROC1 (CRL3), a subfamily of CRLs, was identified to specifically interact with TNFAIP1 and promote its polyubiquitination and degradation. Mechanistically, BTBD9, a specific adaptor component of CRL3 complex, was further defined to bind and promote the ubiquitination and degradation of TNFAIP1 in cells. As such, downregulation of BTBD9 promoted lung cancer cell migration by upregulating the expression of TNFAIP1, whereas TNFAIP1 deletion abrogated this effect. Finally, bioinformatics and clinical sample analyses revealed that BTBD9 was downregulated while TNFAIP1 was overexpressed in human lung cancer, which was associated with poor overall survival of patients. Taken together, these findings reveal a previously unrecognized mechanism by which the CRL3^BTBD9 ubiquitin ligase controls TNFAIP1 degradation to regulate cancer cell migration.

Tumor Necrosis Factor Alpha-Induced Proteins in Malignant Tumors: Progress and Prospects

Tumor necrosis factor (TNF) is the first cytokine used in tumor biotherapy, but TNF-related drugs are limited by the lack of specific targets. Tumor necrosis factor alpha-induced proteins (TNFAIPs), derived from TNF, is a protein family and participates in proliferation, invasion and metastasis of tumor cells. In order to better understand biological functions and potential roles of TNFAIPs in malignant tumors, this paper in the form of “Gene–Protein–Tumor correlation” summarizes the biological characteristics, physiological functions and mechanisms of TNFAIPs by searching National Center of Biotechnology Information, GeneCards, UniProt and STRING databases. The relationship between TNFAIPs and malignant tumors is analyzed, and protein–protein interaction diagram in members of TNFAIPs is drawn based on TNF for the first time. We find that TNF as a key factor is related to TNFAIP1, TNFAIP3, TNFAIP5, TNFAIP6, TNFAIP8 and TNFAIP9, which can be directly involved in activating TNFAIP1, TNFAIP5, TNFAIP8 and TNFAIP9. We confirm that the mechanism of TNFAIP1, TNFAIP2 and TNFAIP3 inducing tumors may be related to NF-κB signaling pathway, but the mechanism of tumor induction by other members of TNFAIPs is not clear. In the future, translational studies are needed to explore the mechanisms of TNF-TNFAIPs-tumors.

Neuroprotective effects of agmatine in antineoplastic drugs induced neurotoxicity: In vitro study

AIMS

The effects of agmatine, an endogenous substance known to have a neuroprotective effect against neurotoxicity has been investigated.

MATERIAL AND METHODS

The primary neuron culture obtained from neonatal rats was exposed to toxicity with paclitaxel and cisplatin and the effect of agmatine on both acute (1 h) and chronic (24 h) exposure was demonstrated by biochemical and molecular analyses. It was demonstrated that the effect of agmatine before and after agmatine was induced by neurotoxicity before agmatine and the effect of agmatine on the formed and occuring toxicities. In addition to the results of cell viability assay, total oxidant capacity and total antioxidant capacity, we have found the opportunity to elaborate on our molecular mechanisms by elaborating our findings with apoptotic and inflammation markers such as caspase 3, kaspase 9 and TNF alpha.

KEY FINDINGS

The results of our study revealed the effect profile of a protective molecule against pathological neural deaths due to neurodegeneration not only in neurotoxicity due to anticancer drugs.

SIGNIFICANCE

In this context, we tried to reverse neurotoxicity due to anticancer drugs by using agmatine the duration (1 and 24 h) and dosage (10-5 M and 10-6 M) determined.

Superhero Rictor promotes cellular differentiation of mouse embryonic stem cells

Embryonic stem cells (ESCs) hold great promise for regenerative medicine. To harness the full therapeutic potential of ESCs, better understanding of the molecular mechanisms underlying the maintenance and differentiation of ESCs is required. Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that integrates growth factor receptor signaling with cellular growth and proliferation. Dysregulation of mTOR signaling has been linked to various human diseases including cancer and metabolic syndromes. However, little is known regarding the function of mTOR signaling in the regulation of ES cell differentiation. Here we report that Rictor, a key component of mTORC2, functions as a novel ES cell differentiation promoting factor. Mechanistically, Rictor is able to interact with Prkch and facilitate Prkch phosphorylation at Ser-642. Upon phosphorylation, Prkch promotes Klf4 phosphorylation and inhibits Klf4-dependent E-cadherin expression, thereafter leading to the ES cell differentiation. These findings reveal a novel Rictor-Prkch-Klf4 pathway that plays an important role in the regulation of ES cell differentiation.

A method for high transfection efficiency in THP-1 suspension cells without PMA treatment

Adherent cells such as mouse RAW cells or human cancer U2OS cells are beneficial to DNA transfection, with 20%-60% transfection efficiency. However, this DNA transfection is rarely used on suspension cells due to its low transfection efficiency (≤5%). We recently found a new DNA transfection method to increase the efficiency up to 13.5% in suspension cells without PMA treatment. We also found that DNA transfection of human TNFAIP1 or CXCL1 recombinant plasmid DNA in THP-1 cells induces a high level of TNF-α protein. Overall, this new method is simple yet efficient and can be used for the overexpression of DNA in suspension cells.

Proinflammatory Factors Mediate Paclitaxel-Induced Impairment of Learning and Memory

The chemotherapeutic agent paclitaxel is widely used for cancer treatment. Paclitaxel treatment impairs learning and memory function, a side effect that reduces the quality of life of cancer survivors. However, the neural mechanisms underlying paclitaxel-induced impairment of learning and memory remain unclear. Paclitaxel treatment leads to proinflammatory factor release and neuronal apoptosis. Thus, we hypothesized that paclitaxel impairs learning and memory function through proinflammatory factor-induced neuronal apoptosis. Neuronal apoptosis was assessed by TUNEL assay in the hippocampus. Protein expression levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the hippocampus tissue were analyzed by Western blot assay. Spatial learning and memory function were determined by using the Morris water maze (MWM) test. Paclitaxel treatment significantly increased the escape latencies and decreased the number of crossing in the MWM test. Furthermore, paclitaxel significantly increased the number of TUNEL-positive neurons in the hippocampus. Also, paclitaxel treatment increased the expression levels of TNF-α and IL-1β in the hippocampus tissue. In addition, the TNF-α synthesis inhibitor thalidomide significantly attenuated the number of paclitaxel-induced TUNEL-positive neurons in the hippocampus and restored the impaired spatial learning and memory function in paclitaxel-treated rats. These data suggest that TNF-α is critically involved in the paclitaxel-induced impairment of learning and memory function.

Effects of XIST/miR-137 axis on neuropathic pain by targeting TNFAIP1 in a rat model

Non-coding RNAs have been reported to participate in the pathophysiology of neuropathic pain. The objective of our study was to investigate the biological role of XIST in neuropathic pain development. In our study, we identify and validate that lncRNA XIST was markedly increased and miR-137 was significantly decreased in chronic constriction injury (CCI) rats. XIST silencing alleviated pain behaviors including both mechanical and thermal hyperalgesia in the CCI rats. XIST was predicted to interact with miR-137 by bioinformatics technology and dual-luciferase reporter assays confirmed the correlation between XIST and miR-137. miR-137 was negatively modulated by XIST and upregulation of miR-137 greatly reduced neuropathic pain development in CCI rats. Moreover, we observed that tumor necrosis factor alpha-induced protein 1 (TNFAIP1) was enhanced in CCI rats and 3'-untranslated region (UTR) of TNFAIP1 was exhibited to be a target of miR-137 by bioinformatics prediction. TNFAIP1 can act as a crucial inflammation regulator by activating NF-kB activity. Overexpression of miR-137 significantly suppressed TNFAIP1 both in vitro and in vivo. Furthermore, upregulation of XIST reversed the inhibitory role of miR-137 in neuropathic pain development by inhibiting TNFAIP1. In conclusion, our current study indicates that XIST can positively regulate neuropathic pain in rats through regulating the expression of miR-137 and TNFAIP1. Our results imply that XIST/miR-137/TNFAIP1 axis may serve as a novel therapeutic target in neuropathic pain.

CXCL12 overexpression promotes the angiogenesis potential of periodontal ligament stem cells

Periodontal ligament stem cells (PDLSCs) are a major source of mesenchymal stem cells (MSCs) in adults and are effective for tissue engineering, like promoting angiogenesis and bone regeneration. CXCL12 has been reported to be involved in the recruitment and engraftment of MSCs in wound sites. However, whether CXCL12 potentiates the angiogenesis of PDLSCs is not clear. In this experiment, we transduced PDLSCs with CXCL12, and evaluated the angiogenesis potential of CXCL12-modified PDLSCs through in vitro and in vivo studies. The results showed that CXCL12 overexpression significantly stimulated the gene and protein expressions of bFGF, VEGF, SCF and PLGF in PDLSCs; CXCL12 gene modified PDLSCs formed longer capillary‐like structure; Moreover, in vivo transplanted PDLSCs transduced with CXCL12 could significantly promote bone tissue repair and angiogenesis in a rat critical-sized calvarial bone defect model. Taken together, our study confirmed that CXCL12 can enhance the angiogenesis potential of PDLSCs, which are crucial in the repair and regeneration of bone tissue.

Mcl-1 stabilization confers resistance to taxol in human gastric cancer

Taxol has been extensively used as an antineoplastic drug to treat human gastric cancer. However, the acquired drug resistance invariably develops and greatly limits the therapeutic efficacy of Taxol. Identification of the underlying resistance mechanisms may inform the development of new therapies of gastric cancers to Taxol treatment. Here we report that upregulation of Mcl-1 (Myeloid cell leukemia-1) confers acquired resistance to Taxol in human gastric cancer. Mcl-1 is shown to be stabilized in Taxol -resistant gastric cancer cells because of the hyper-activation of the PI3K/Akt signaling pathway. The increased Mcl-1 prevents of the permeabilization of the outer mitochondrial membrane, thereby blocking the Taxol-induced apoptosis. Furthermore, inhibition of Mcl-1 or PI3K/Akt pathway significantly reversed the resistant phenotype of Taxol-resistant human gastric cancer cells. Taken together, our findings broaden the view of PI3K/Akt pathway as an important regulator in Taxol acquired resistance, and implicate Mcl-1 as a specific therapeutic target for the treatment of Taxol-resistant human gastric cancer.

Human Stem Cells Overexpressing miR-21 Promote Angiogenesis in Critical Limb Ischemia by Targeting CHIP to Enhance HIF-1α Activity

Critical limb ischemia (CLI) is a severe blockage in the arteries of the lower extremities. However, the effective and optimal treatment for CLI remains to be elucidated. Previous therapeutic research is mainly focused on proangiogenic growth factors administrations. Recently, miR-21 has been revealed to play a crucial role in angiogenesis. Thus, we hypothesize that miR-21 over-expression in human umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) can effectively treat CLI. Herein, UCBMSCs were transduced with lentivirus-miR-21-Luciferase (Lenti-miR-21) or lentivirus- LacZ-Luciferase (Lenti-LacZ). The results indicated that miR-21 induced UCBMSCs proliferation, migration, and angiogenesis in vitro. Subsequently, general observation and laser Doppler perfusion imaging were introduced to detect perfusion in muscles of CLI-nude mice on 1, 4, 7, 14, and 28 day postoperation. There was a significant improvement in blood vessels of the ischemic limb in Lenti-miR-21 group at 7 day compared with the saline or Lenti-LacZ groups. At 28 day, histological analysis confirmed that UCBMSCs over-expressing miR-21 increased neovascularization in CLI. Furthermore, carboxyl terminus of Hsc70-interacting protein (CHIP) was found to be the target gene for miR-21-mediated activation of hypoxia-inducible factor 1α (HIF-1α) in UCBMSCs. In summary, our study demonstrated that over-expressing miR-21 in UCBMSCs could improve neovascularization in CLI through enhancing HIF-1α activity by targeting CHIP, which may hold great therapeutic promise in treating CLI.