Implication of TIPE2 Expression on the Malignant Transformation of Oral Leukoplakia.

BACKGROUND/AIM: Identification of biomarkers involved in the malignant transformation of oral leukoplakia (OL) is required for the early diagnosis and management of patients with OL. This study aimed to evaluate the functions of tumor necrosis factor-alpha-induced protein 8-like 2 (TIPE2) expression in the malignant transformation of OL. MATERIALS AND METHODS: The expression levels of TIPE2 and dormant cell markers phospho-ERK and phospho-p38 in a cohort containing 103 surgical specimens from patients with OL were evaluated using immunohistochemistry. The influence of TIPE2 expression on the biological behavior of the immortalized human oral keratinocyte (IHOK) line was investigated in vitro. RESULTS: Increased TIPE2 expression was detected in 40 (38.8%) patients with OL. In a multivariate analysis using clinicopathological variables and TIPE2 expression as cofactors, the presence of dysplasia (p=0.003) and TIPE2 abundance (p=0.019) were identified as independent risk factors for the malignant transformation of OL. Moreover, the in vitro analysis revealed that TIPE2 knockdown can promote the proliferating ability of IHOK; however, the number of apoptotic cells also increased after TIPE2 knockdown in IHOK. Furthermore, TIPE2 expression was significantly associated with phospho-p38 expression, a dormant cell marker, in our cohort (p=0.047). CONCLUSION: TIPE2 expression may contribute to the malignant transformation of OL, and its function may be related to cellular dormancy in OL pathogenesis.

Hepatocyte TIPE2 is a fasting-induced Raf-1 inactivator that drives hepatic gluconeogenesis to maintain glucose homeostasis.

BACKGROUND: The liver regulates metabolic balance during fasting-feeding cycle. Hepatic adaptation to fasting is precisely modulated on multiple levels. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is a negative regulator of immunity that reduces several liver pathologies, but its physiological roles in hepatic metabolism are largely unknown. METHODS: TIPE2 expression was examined in mouse liver during fasting-feeding cycle. TIPE2-knockout mice, liver-specific TIPE2-knockout mice, liver-specific TIPE2-overexpressed mice were examined for fasting blood glucose and pyruvate tolerance test. Primary hepatocytes or liver tissues from these mice were evaluated for glucose production, lipid accumulation, gene expression and regulatory pathways. TIPE2 interaction with Raf-1 and TIPE2 transcription regulated by PPAR-α were examined using gene overexpression or knockdown, co-immunoprecipitation, western blot, luciferase reporter assay and DNA-protein binding assay. RESULTS: TIPE2 expression was upregulated in fasted mouse liver and starved hepatocytes, which was positively correlated with gluconeogenic genes. Liver-specific TIPE2 deficiency impaired blood glucose homeostasis and gluconeogenic capacity in mice upon fasting, while liver-specific TIPE2 overexpression elevated fasting blood glucose and hepatic gluconeogenesis in mice. In primary hepatocytes upon starvation, TIPE2 interacted with Raf-1 to accelerate its ubiquitination and degradation, resulting in ERK deactivation and FOXO1 maintenance to sustain gluconeogenesis. During prolonged fasting, hepatic TIPE2 deficiency caused aberrant activation of ERK-mTORC1 axis that increased hepatic lipid accumulation via lipogenesis. In hepatocytes upon starvation, PPAR-α bound with TIPE2 promoter and triggered its transcriptional expression. CONCLUSIONS: Hepatocyte TIPE2 is a PPAR-α-induced Raf-1 inactivator that sustains hepatic gluconeogenesis and prevents excessive hepatic lipid accumulation, playing beneficial roles in hepatocyte adaptation to fasting.

TIPE2 ameliorates neuroinflammation and cognitive impairment in sepsis-associated encephalopathy through regulating RhoA/ROCK2-NF-κB signaling pathway.

Sepsis-associated encephalopathy (SAE) is an acute brain dysfunction induced by systemic inflammation caused by sepsis and is one of the most common types of encephalopathy in intensive care units. Deteriorative neuroinflammation is closely related to the development of brain injury, which often transforms into common pathological manifestations in patients with severe sepsis. Therefore, taking necessary preventive and protective measures for potential brain injury and promptly reducing neuroinflammatory injury is necessary to improve the long-term prognoses of patients. Tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) can play a significant protective role in septic lung injury, but studies on its expression and role in neurological diseases are rare. In the present study, we found that TIPE2 can expressed in microglia and ameliorate brain injury caused by SAE by suppressing neuroinflammation. The RhoA/ROCK2 pathway is the central coordinator of tissue injury response, and the activation of RhoA participates in the lipopolysaccharide-induced activation of the nuclear factor kappa B (NF-κB) signaling pathway. The activation of RhoA and phosphorylation of NF-κB was enhanced after TIPE2 deficiency. Importantly, TIPE2 negatively regulates inflammatory responses in vivo and in vitro and plays a protective role in SAE by inhibiting the activation of RhoA/ROCK2-NF-κB signaling pathways. The ultimate aim of our proposed project is to provide a theoretical basis for the development of a novel strategy for the early prevention and therapy of SAE.

Tumor necrosis factor-α-induced protein 8-like 2 alleviates morphine antinociceptive tolerance through reduction of ROS-mediated apoptosis and MAPK/NF-κB signaling pathways.

Chronic morphine tolerance is a repulsive barrier to the clinical treatment of pain. Whereas the underlying molecular mechanisms of morphine tolerance remain unknown. Here, we proposed that tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) is an essential control point regarding the progression of chronic morphine antinociceptive tolerance. We found that TIPE2 levels in the lumbar spinal cord were significantly downregulated in the morphine tolerance mouse model. Specifically, decreased TIPE2 by morphine tolerance was primarily expressed in spinal neurons, while increased expression of spinal TIPE2 distinctly attenuated the chronic morphine antinociceptive tolerance and tolerance-associated hyperalgesia. We also observed that increased expression of spinal TIPE2 significantly reduced morphine tolerance-induced neuronal ROS production and apoptosis, along with the activation of MAPKs and NF-κB signaling pathways. Moreover, the increased TIPE2 expression inhibited neuronal activation and glial reactivity in the spinal dorsal horn after chronic morphine exposure. Additionally, TIPE2 overexpression in cultured SH-SY5Y cells significantly suppressed ROS production and apoptosis in response to morphine challenge. Therefore, we can conclude that the upregulation of spinal TIPE2 may attenuate the morphine antinociceptive tolerance via TIPE2-dependent downregulation of neuronal ROS, inhibition of neuronal apoptosis, suppression of MAPKs and NF-κB activation. TIPE2 may be a potential strategy for preventing morphine tolerance in the future studies and clinical settings.

Research progress of TIPE2 in immune-related diseases.

The tumor necrosis factor α-induced protein 8 (TNFAIP8) family, which consists of TNFAIP8 (TIPE), TNFAIP8L1 (TIPE1), TNFAIP8L2 (TIPE2) and TNFAIP8L3 (TIPE3), has recently emerged as a regulatory factor involved in immune response and tumorigenesis. Among its members, TIPE2 acts as a negative regulator of both innate and adaptive immunity, playing a crucial role in maintaining immune homeostasis by negatively regulating T cell receptor (TCR) and toll-like receptor (TLR) signal transduction. Immune homeostasis is an indispensable characteristic of the immune system, which prevents harmful inflammatory reactions and ensures the proper functioning of the body. A large number of studies have shown that abnormal TIPE2 expression exists in a variety of inflammation-related diseases such as asthma, colitis, and systemic lupus erythematosus, highlighting the importance of comprehending its function for the prevention and treatment of immune-related conditions. This review aims to provide an overview of the in vivo distribution and expression of TIPE2, its regulatory role in central and peripheral immune-related diseases, and the underlying mechanisms that govern its function in the inflammatory response. By delving into these aspects, a deeper understanding of the role and functionality of TIPE2 in inflammatory responses can be achieved.

TIPE2 regulates the response of BV2 cells to lipopolysaccharide by the crosstalk between PI3K/AKT signaling and microglia M1/M2 polarization.

Tumor necrosis factor (TNF)-α-induced protein 8-like 2 (TIPE2) is a crucial negative regulator of both adaptive and innate immunity, which helps maintain the dynamic balance of the immune system by negatively regulating the signaling of T-cell receptors (TCR) and Toll-like receptors (TLR). In this study, we aimed to investigate the role and molecular mechanism of TIPE2 using a lipopolysaccharide (LPS)-induced inflammatory injury model in BV2 cells. Specifically, we constructed a BV2 cell line of TIPE2-overexpression or TIPE2-knockdown via lentiviral transfection. Our results demonstrated that overexpression of TIPE2 downregulated the expression of pro-inflammatory cytokines IL-1ß and IL-6, which was reversed by knockdown of TIPE2 in the inflammation model of BV2 cells. In addition, overexpression of TIPE2 resulted in the conversion of BV2 cells to the M2 phenotype, while the knockdown of TIPE2 promoted the transformation of BV2 cells to the M1 phenotype. Notably, our co-culture experiments with neuronal cells SH-SY5Y showed that the overexpression of TIPE2 in inflammation-injured BV2 cells exhibited a protective effect on the neuronal cells. Finally, western blot analysis demonstrated that TIPE2 significantly reduced the expression of p-PI3K, p-AKT, p-p65, and p-IκBα in LPS treated BV2 cells, and inhibited the activation of NF-κB through the dephosphorylation of PI3K/AKT. These results suggest that TIPE2 plays an important role in mediating neuroinflammatory responses and may be involved in neuroprotection by modulating the phenotypic changes of BV2 cells and regulating the pro-inflammatory responses through the PI3K/AKT and NF-κB signaling pathways. In conclusion, our study provides new insights into the crucial role of TIPE2 in regulating neuroinflammatory responses and highlights its potential as a therapeutic target for neuroprotection.

TIPE2 deficiency prolongs mouse heart allograft survival by facilitating immature DCs-induced Treg generation.

It has been reported that deletion of tumor necrosis factor-α-induced protein-8 like 2 (TNFAIP8L2, TIPE2) facilitates the activation of T-cell receptors. However, the role of TIPE2 in T-cell-mediated acute transplant rejection remains unclear. To illustrate the underlying cellular mechanisms, we transplanted BALB/c hearts into C57BL/6 wild-type (WT) or C57BL/6 mice deficient for TIPE2 (TIPE2-/-) and found that TIPE2-/- recipient mice showed significantly prolonged survival of heart allografts and suppressed maturation of CD11c+ dendritic cells (DCs), which largely abolished the activation and proliferation of alloreactive T cells and their cytotoxic activity. TIPE2-/- DCs increased CD4+CD25+Foxp3+CD127- regulatory T cells (Tregs)generation, likely by inhibiting DCs maturation and CD80 and CD86 expression. Administration of anti-CD25 abolished the allograft survival induced by TIPE2 deficiency. Moreover, TIPE2 deficiency increased IL-10 production in T cells and in recipient serum and allografts. Mechanistic studies revealed that TIPE2-/- restrained the maturation of DCs via inhibition of PI3K/AKT phosphorylation during alloantigen stimulation. Taken together, TIPE2 deficiency in recipient mice inhibited acute rejection by increasing Tregs generated by immature DCs. Thus, TIPE2 could be a therapeutic target for suppressing rejection in organ transplantation.

TIPE2 knockdown exacerbates isoflurane-induced postoperative cognitive impairment in mice by inducing activation of STAT3 and NF-κB signaling pathways.

Objective: Anesthetic exposure causes learning and memory impairment, the mechanisms of which remain unknown. It has been reported that tumor necrosis factor-α-inducer protein 8-like 2 (TIPE2) is a newly discovered immune negative regulator that is essential for maintaining immune homeostasis. This study aimed to examine the role of TIPE2 in isoflurane-induced postoperative cognitive decline (POCD). Methods: An AAV empty vector and AAV shTIPE2 vector for the knockdown of TIPE2 were injected into the dorsal hippocampus of mice. Mice were continuously exposed to 1.5% isoflurane followed by abdominal exploration. Behavioral tests including the open field test and fear conditioning test were performed on the third and fourth day post-operation. Apoptosis was detected by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling staining. The kits were used to detect the activity of antioxidant enzymes. Inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay. Signal transducer and activator of transcription 3 (STAT3) and nuclear factor-κB (NF-κB) signaling pathway activities were detected by western blotting. Results: TIPE2 expression increased after isoflurane anesthesia and surgery. TIPE2 deficiency aggravated cognitive impairment in mice and further caused apoptosis and oxidative stress in hippocampal neurons. TIPE2 deficiency induced microglial activation and increased secretion of proinflammatory cytokines. In addition, TIPE2 deficiency promoted STAT3 and NF-κB signaling activation induced by isoflurane anesthesia and after surgery. Conclusion: TIPE2 may play a neuroprotective role in POCD by regulating STAT3 and NF-κB pathways.

TIPE2 Inhibits MGD Inflammation by Regulating Macrophage Polarization.

BACKGROUND: The aim of this study was to decide the role of the polarization of macrophages regulated by tumor necrosis factor-α (TNF-α)-induced protein 8-like 2 (TIPE2) in meibomian gland dysfunction (MGD). METHODS: Firstly, the secretory function of the meibomian gland (MG) in apolipoprotein E knockout (ApoE-/-) MGD mice and normal mice was detected by oil red staining. Then, the expression levels of markers of M1 and M2 macrophages were detected by immunofluorescence staining in MGD, normal mice, and mild and severe MGD corpses to decide the role of M1 and M2 macrophages in MGD inflammation. Meanwhile, the expression levels of TIPE2 in MGD mice and MGD patients were detected by immunofluorescence staining, and the correlations among TIPE2, M1 and M2 macrophages were analyzed by immunofluorescence double staining in MGD mice and MGD patients. Furthermore, lipopolysaccharide (LPS) and interleulkin-4 (IL-4) were used to induce M1 and M2 polarization of macrophages, and the mRNA level of TIPE2 was detected in M1 and M2 macrophages. RESULTS: Oil red staining showed that eyelid fat congestion was more severe in (ApoE-/-) MGD mice than in normal mice, and the M1 macrophage was the primary inflammatory cell infiltrated in (ApoE-/-) MGD mice (p < 0.05). The results of the immunofluorescence staining showed that the infiltration of macrophages in MGD mice was more obvious than that in the normal group, and M1 macrophage was the dominant group (p < 0.05). Similar to the results of the MGD mouse model, more macrophage infiltration was observed in MGD patients' MG tissues, and there were more M1 cells in the severe group than in the mild group (p < 0.05). Moreover, the expression of TIPE2 was positively correlated with the expression of M2 macrophages in MGD patients and mice MG tissues (p < 0.05). The expression of TIPE2 mRNA in LPS-induced M1 macrophages declined, while the expression of TIPE2 mRNA in IL-4-induced M2 macrophages increased (p < 0.05). CONCLUSION: M1 macrophage was the dominant group infiltrated in the MG tissue of MGD, and TIPE2 is a potential anti-inflammatory target for preventing the development of MGD by promoting the M2 polarization of macrophages.

TIPE2 sensitizes breast cancer cells to paclitaxel by suppressing drug-induced autophagy and cancer stem cell properties.

Drug resistance is a great obstacle to the clinical application of paclitaxel (PTX) in breast cancer treatment. Chemoresistance can be either primary or acquired. Multifarious factors are related to drug resistance. Among these factors, drug-induced autophagy has been shown to contribute to acquired chemoresistance in cancer cells. Additionally, cancer stem cells (CSCs) drive primary chemoresistance. Recent advances regarding TIPE2 demonstrate that TIPE2 enhances osteosarcoma and non-small cell lung cancer cell sensitivity to cisplatin. However, the role of TIPE2 in PTX resistance in breast cancer cells has not been elucidated. Here, the in vitro and in vivo study demonstrated that TIPE2 sensitized breast cancer cells to PTX by suppressing drug-induced autophagy and CSC properties. Mechanistically, we found that TIPE2 activated the AKT/mTOR signalling pathway and inhibited the TAK1/MAPK signalling pathway to suppress drug-induced autophagy. Moreover, TIPE2 inhibited TAK1/NF-κB activation to reduce breast CSC properties. Collectively, our results first elucidated the inhibitory role of TIPE2 in breast cancer chemoresistance. Thus, TIPE2 may be a new target for breast cancer chemotherapy.

Long noncoding RNA HOXA-AS2 ameliorates chronic intermittent hypoxia-induced lung inflammation by regulating miR-17-5p/tipe2 axis.

PURPOSE: The purpose is to confirm whether long noncoding RNA HOXA-AS2 relieves chronic intermittent hypoxia (CIH)-induced lung inflammation. METHODS: Male Sprague Dawley rats were used to establisha CIH rat model. Hematoxylin and Eosin staining was used on the lung tissue injury to determine the successful construction of CIH animal model. Arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2) were measured. HOXA-AS2 was overexpressed to evaluate its role in the progression and development of CIH. T cell differentiation and cytokine production were determined using flow cytometry. Cell apoptosis was determined using terminal deoxynucleotidyl transferase dUTP nick end labelling assay kit. The target of HOXA-AS2 and miR-17-5p was predicted by the Encyclopedia of RNA Interactomes (ENCORI) and confirmed using luciferase assay. RESULTS: HOXA-AS2 was downregulated in CIH rat models. Lung tissue injury was observed in CIH rats, and the injury was attenuated by the overexpression of HOXA-AS2. PaO2 was reduced and PaCO2 was induced in CIH rats, which was reversed by the overexpression of HOXA-AS2. The overexpression of HOXA-AS2 inhibited CIH-induced cell apoptosis. It also reversed alterations in the levels of interferon gamma (IFNγ), interleukin (IL)-2, IL-6, IL-1ß, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta1 (TGF-ß1) in rats caused by CIH. The overexpression of HOXA-AS2 prevented the induction in CD4+ IFN-γ+ T cells and reduction in CD4+TGF-ß1+ T cells. The overexpression of HOXA-AS2 upregulated tumor necrosis factor-alpha-induced protein 8-like 2 (tipe2) key regulator through directly targeting miR-17-5p. Further experiments proved that tipe2 was the direct target of miR-17-5p. CONCLUSION: This study manifested that HOXA-AS2 acted as an anti-inflammatory regulator and protected lung tissue injury from CIH in the rat model; this was mediated by upregulation of tipe2 through directly targeting miR-17-5p. HOXA-AS2 upregulated the expression of tipe2, providing new understanding and therapeutic target for CIH.

Long noncoding RNA HOXA-AS2 ameliorates chronic intermittent hypoxia-induced lung inflammation by regulating miR-17-5p/tipe2 axis

Purpose: The purpose is to confirm whether long noncoding RNA HOXA-AS2 relieves chronic intermittent hypoxia (CIH)-induced lung inflammation. Methods: Male Sprague Dawley rats were used to establisha CIH rat model. Hematoxylin and Eosin staining was used on the lung tissue injury to determine the successful construction of CIH animal model. Arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2) were measured. HOXA-AS2 was overexpressed to evaluate its role in the progression and development of CIH. T cell differentiation and cytokine production were determined using flow cytometry. Cell apoptosis was determined using terminal deoxynucleotidyl transferase dUTP nick end labelling assay kit. The target of HOXA-AS2 and miR-17-5p was predicted by the Encyclopedia of RNA Interactomes (ENCORI) and confirmed using luciferase assay. Results: HOXA-AS2 was downregulated in CIH rat models. Lung tissue injury was observed in CIH rats, and the injury was attenuated by the overexpression of HOXA-AS2. PaO2 was reduced and PaCO2 was induced in CIH rats, which was reversed by the overexpression of HOXA-AS2. The overexpression of HOXA-AS2 inhibited CIH-induced cell apoptosis. It also reversed alterations in the levels of interferon gamma (IFNγ), interleukin (IL)-2, IL-6, IL-1β, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta1 (TGF-β1) in rats caused by CIH. The overexpression of HOXA-AS2 prevented the induction in CD4+ IFN-γ+ T cells and reduction in CD4+TGF-β1+ T cells. The overexpression of HOXA-AS2 upregulated tumor necrosis factor-alpha-induced protein 8-like 2 (tipe2) key regulator through directly targeting miR-17-5p. Further experiments proved that tipe2 was the direct target of miR-17-5p (AU)

TIPE-2 ameliorates inflammatory bowel disease in mice via inhibiting STAT3 and NF-kB activation.

TIPE-2 has been identified as a negative regulator of both innate and adaptive immunity and is involved in several inflammatory diseases. However, the immune inhibition mechanism of TIPE-2 involved in inflammatory bowel disease has not been well studied. Therefore, the aim of this study was to investigate whether TIPE-2 improved experimental colitis by reducing high levels of inflammation in the intestine. Lentivirus encoding TIPE-2 was administered to mice by intrarectal injection after colitis induction. Histological analysis was used to analyze sections of the intestine. Protein expression induced by STAT3 and NF-κB signaling was analyzed by western blot. We found that TIPE-2 reduced the colitis activity index score and the histological score of the intestine. TIPE-2 also decreased inflammatory cytokine levels in the intestine. Additionally, TIPE-2 inhibited STAT3 and NF-kB activation. These results suggested that TIPE-2 might attenuate inflammation of colitis via inhibiting of STAT3 and NF-kB activation.

TIPE2 acts as a tumor suppressor and correlates with tumor microenvironment immunity in epithelial ovarian cancer.

BACKGROUND: Epithelial ovarian cancer (EOC) is one of the deadliest gynecologic cancers. The etiology of EOC has still not been elucidated thoroughly. Tumor necrosis factor-α-induced protein 8-like2 (TNFAIP8L2, TIPE2), an important regulator of inflammation and immune homeostasis, plays a critical role in the progression of various cancers. This study aims to investigate the role of TIPE2 in EOC. METHODS: Expression of TIPE2 protein and mRNA in EOC tissues and cell lines was examined using Western blot and quantitative real-time PCR (qRT-PCR). The functions of TIPE2 in EOC were investigated by cell proliferation assay, colony assay, transwell assay, and apoptosis analysis in vitro. To further investigate the regulatory mechanisms of TIPE2 in EOC, RNA-seq and western blot were performed. Finally, the CIBERSORT algorithm and databases including Tumor Immune Single-cell Hub (TISCH), Tumor Immune Estimation Resource (TIMER), Tumor-Immune System Interaction (TISIDB), and The Gene Expression Profiling Interactive Analysis (GEPIA) were used to elucidate its potential role in regulating tumor immune infiltration in the tumor microenvironment (TME). RESULTS: TIPE2 expression was shown to be considerably lower in both EOC samples and cell lines. Overexpression of TIPE2 suppressed EOC cell proliferation, colony formation, and motility in vitro. Mechanistically, TIPE2 suppressed EOC by blocking the PI3K/Akt signaling pathway, according to bioinformatics analysis and western blot in TIPE2 overexpression EOC cell lines, and the anti-oncogenic potentials of TIPE2 in EOC cells could be partially abrogated by the PI3K agonist, 740Y-P. Finally, TIPE2 expression was positively associated with various immune cells and possibly involved in the regulation of macrophage polarization in ovarian cancer. CONCLUSIONS: We detail the regulatory mechanism of TIPE2 in EOC carcinogenesis, as well as how it correlates with immune infiltration, emphasizing its potential as a therapeutic target in ovarian cancer.

TIPE2 knockout reduces myocardial cell damage by inhibiting IFN-γ-mediated ferroptosis.

Acute rejection of the transplanted heart is mediated by oxidative programmed cell death through the synergistic effects of the innate and adaptive immune systems. However, the role of ferroptosis, a newly discovered form of oxidative cell death, has not been widely evaluated. Tumor necrosis factor-α-induced protein-8 like 2 (TNFAIP8L2), also known as TIPE2, is required for maintaining immune homeostasis. To characterize the role of TIPE2 in mediating heart allografts, BALB/c hearts were transplanted into C57BL/6 wild-type (WT) and TIPE2-/- recipient mice. In TIPE2-/- recipient mice, allograft injury in BALB/c allograft hearts was significantly reduced through the inhibition of allograft ferroptosis. On day 3 and day 6 post-transplantation, the numbers of CD3+, CD4+, and CD8+ cells among splenocytes and draining lymph node cells were significantly decreased, and the activation of CD4+ and CD8+ cells in grafts was decreased in TIPE2-/- recipient mice compared with WT mice. Moreover, CD4+ and CD8+ T cells in TIPE2-/- recipient mice were characterized by deficient capacities for interferon-γ (IFN-γ) production through the TBK1 signaling axis and increased glutathione peroxidase 4 (GPX4). In cell experiments, treatment with IFN-γ enhanced ferroptosis-specific lipid peroxidation in myocardial cells and correlated inversely with GPX4 expression. Mechanistically, IFN-γ administration decreased the expression of GPX4 by inhibiting MEK/ERK phosphorylation. In summary, our findings demonstrated that TIPE2 deficiency inhibits T-cell production of IFN-γ to reduce ferroptosis in allografts by restraining lipid peroxidation.

Different exposure modes of PM2.5 induces bronchial asthma and fibrosis in male rats through macrophage activation and immune imbalance induced by TIPE2 methylation.

Exposure to PM2.5 can aggravate the occurrence and development of bronchial asthma and fibrosis. Here, we investigated the differences in bronchial injury caused by different exposure modes of PM2.5 (high concentration intermittent exposure and low concentration continuous exposure), and the mechanism of macrophage activation and respiratory immune imbalance induced by PM2.5, leading to bronchial asthma and airway fibrosis using animal and cell models. A "PM2.5 real-time online concentrated animal whole-body exposure system" was used to conduct PM2.5 respiratory exposure of Wistar rats for 12 weeks, which can enhance oxidative stress in rat bronchus, activate epithelial cells and macrophages, release chemokines, recruit inflammatory cells, release inflammatory factors and extracellular matrix, promote bronchial mucus hypersecretion, inhibit the expression of epithelial cytoskeletal proteins, destroy airway barrier, and induce asthma. Furthermore, PM2.5 induced M2 polarization in lung bronchial macrophages through JAK/STAT and PI3K/Akt signaling pathways, and compared with low concentration continuous exposure, high concentration intermittent exposure of PM2.5 could regulate significantly higher expression of TIPE2 protein through promoter methylation of TIPE2 DNA, thereby activating PI3K/Akt signaling pathway and more effectively inducing M2 polarization of macrophages. Additionally, activated macrophages release IL-23, and activated epithelial cells and macrophages released TGF-ß1, which promoted the differentiation of Th17 cells, triggered the Th17 dominant immune response, and activated the TGF-ß1/Smad2 signaling pathway, finally causing bronchial fibrosis. Moreover, when the total amount of PM2.5 exposure was equal, high concentration-intermittent exposure was more serious than low concentration-continuous exposure. In vitro experiments, the co-culture models of PM2.5 with BEAS-2B, WL-38 and rat primary alveolar macrophages further confirmed that PM2.5 could induce the macrophage activation through oxidative stress and TIPE2 DNA methylation, and activate the TGF-ß1/Smad2 signaling pathway, leading to the occurrence of bronchial fibrosis.

Comprehensive analysis of tumor necrosis factor-α-inducible protein 8-like 2 (TIPE2): A potential novel pan-cancer immune checkpoint.

Tumor necrosis factor-α-inducible protein 8-like 2 (TIPE2) is encoded by TNFAIP8L2 and is a newly identified negative regulator of natural and acquired immunity that plays a critical function in maintaining immune homeostasis. Recently, CAR-NK immune cell therapy has been a focus of major research efforts as a novel cancer therapeutic strategy. TIPE2 is a potential checkpoint molecule for immune cell maturation and antitumor immunity that could be used as a novel NK cell-based immunotherapeutic approach. In this study, we explored the expression of TNFAIP8L2 across various tumor types and found that TNFAIP8L2 was highly expressed in most tumor types and correlated with prognosis. Survival analysis showed that TNFAIP8L2 expression was predictive of improved survival in cervical-squamous-cell-carcinoma (CESC), sarcoma (SARC) and skin-cutaneous-melanoma (SKCM). Conversely, TNFAIP8L2 expression predicted poorer survival in acute myeloid leukemia (LAML), lower-grade-glioma (LGG), kidney-renal-clear-cell-carcinoma (KIRC) and uveal-melanoma (UVM). Analysis of stemness features and immune cell infiltration indicated that TNFAIP8L2 was significantly associated with cancer stem cell index and increased macrophage and dendritic cell infiltration. Our data suggest that TNFAIP8L2 may be a novel immune checkpoint biomarker across different tumor types, particularly in LAML, LGG, KIRC and UVM, and may have further utility as a potential target for immunotherapy.

TIPE2 attenuates neuroinflammation and brain injury through Bcl-2/Bax/cleaved caspase-3 apoptotic pathways after intracerebral hemorrhage in mice.

BACKGROUND: Intracerebral hemorrhage (ICH) is a serious disease with high mortality and morbidity, and effective treatment is limited. A large amount of evidence suggests that the inflammatory response contributes to secondary brain damage following ICH. TIPE2 is an essential negative regulator of both innate and adaptive immunity, and depletion of TIPE2 causes inflammatory disease. However, the possible role of TIPE2 following ICH has not been reported. METHODS: In this study, we investigated TIPE2 levels and inflammation in microglia treated with erythrocyte lysate in vitro. In addition, we analyzed the role of Bcl-2/Bax/cleaved caspase-3 apoptotic pathways in ICH mice. Furthermore, we observed proinflammatory cytokine production, BBB disruption, cerebral water content and neurological damage in ICH mice. RESULTS: We found that TIPE2 levels were significantly decreased in erythrocyte lysate-treated microglia compared to control microglia.Upregulation of TIPE2 decreased microglia activation and cytokine production and accelerated brain damage in ICH mice. Furthermore, upregulation of TIPE2 decreased the higher ratio of Blc-2/Bax and increased cleaved caspase-3 levels in ICH mice. In addition, upregulation of TIPE2 attenuated proinflammatory cytokine production, BBB disruption, and severe brain inflammation after ICH. CONCLUSION: These results demonstrated that TIPE2 was negatively correlated with the pathogenesis of ICH, which prevented brain injury and attenuated deleterious inflammatory responses following ICH. TIPE2 might serve as a novel target for ICH therapy.

TIPE2 Inhibits Migration and Promotes Apoptosis as a Tumor Suppressor in Hypopharyngeal Carcinoma.

BACKGROUND: Hypopharyngeal squamous cell carcinoma (HSCC) is a common malignant cancer characterized by high metastasis and infiltration. The development of new approaches for the early diagnosis and identification of new therapeutic targets is essential. TIPE2 is well known as a tumor suppressor and related to a favorable prognosis of HSCC. However, its underlying mechanism remains unclear. METHODS AND MATERIALS: TIPE2 expression was determined by immunohistochemistry and RT-qPCR. A TIPE2 overexpression stable cell line was generated by lentivirus infection. TIPE2 and other related protein levels were detected by western blotting. The cell cycle and apoptosis were performed by flow cytometric analysis. Cell proliferation was measured with a Cell Counting Kit-8 (CCK-8) assay, and the activity of caspase-3 and caspase-7 was assessed by Caspase-Glo® 3/7 Assay. All data were analyzed with SPSS 25 and GraphPad Prism 8.0. RESULTS: TIPE2 expression was significantly down-regulated in HSCC. Low TIPE2 expression may be associated with poor prognosis in HSCC. TIPE2 overexpression markedly inhibited tumor cell migration. Moreover, TIPE2 decreased cell proliferation but promoted apoptosis. TIPE2 suppressed tumor growth by activating Epithelial-Mesenchymal Transition (EMT) and the extrinsic apoptosis pathway. CONCLUSION: TIPE2 inhibited tumor progression by suppressing cell migration but promoting apoptosis. TIPE2 can be a new therapeutic target in HSCC.

Genistein promotes M1 macrophage apoptosis and reduces inflammatory response by disrupting miR-21/TIPE2 pathway.

Cardiovascular diseases are a major cause of mortality, and vascular injury, a common pathological basis of cardiovascular disease, is deeply correlated with macrophage apoptosis and inflammatory response. Genistein, a type of phytoestrogen, exerts cardiovascular protective activities, but the underlying mechanism has not been fully elucidated. In this study, RAW264.7 cells were treated with genistein, lipopolysaccharide (LPS), nuclear factor-kappa B (NF-κB) inhibitor, and/or protein kinase B (AKT) agonist to determine the role of genistein in apoptosis and inflammation in LPS-stimulated cells. Simultaneously, high fat diet-fed C57BL/6 mice were administered genistein to evaluate the function of genistein on LPS-induced cardiovascular injury mouse model. Here, we demonstrated that LPS obviously increased apoptosis resistance and inflammatory response of macrophages by promoting miR-21 expression, and miR-21 downregulated tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) expression by targeting the coding region. Genistein reduced miR-21 expression by inhibiting NF-κB, then blocked toll-like receptor 4 (TLR4) pathway and AKT phosphorylation dependent on TIPE2, resulting in inhibition of LPS. Our research suggests that miR-21/TIPE2 pathway is involved in M1 macrophage apoptosis and inflammatory response, and genistein inhibits the progression of LPS-induced cardiovascular injury at the epigenetic level via regulating the promoter region of Vmp1 by NF-κB.