Overexpression of homeodomain-interacting protein kinase 2 (HIPK2) attenuates sepsis-mediated liver injury by restoring autophagy

miR-664a-5p promotes experimental membranous nephropathy progression through HIPK2/Calpain1/GSα-mediated autophagy inhibition

We previously found that miR-664a-5p is specifically expressed in urinary exosomes of idiopathic membranous nephropathy (IMN) patients. Homeodomain-interacting protein kinase 2 (HIPK2), a nuclear serine/threonine kinase, plays an important role in nephropathy. But the function of these factors and their connection in MN are unclear. To investigate the function and mechanism of miR-664a-5p in MN, the miR-664a-5p expression in HK-2 cells, exosomes, podocytes and renal tissues were studied, as well as cell growth and apoptosis of these cells, the binding of miR-664a-5p to HIPK2 mRNA, the levels of relative proteins and autophagy. The MN progression in MN mice model was also studied. Albumin increased the miR-664a-5p content and apoptosis of HK-2 cells, which was blocked by miR-664a-5p antagomir. miR-664a-5p bound to the 3' UTR of HIPK2 mRNA, resulting in the up-regulation of Calpain1, GSα shear and the inhibition of autophagy level. Autophagy inhibitor CQ blocked the protective effect of miR-664a-5p antagomir, HIPK2 overexpression, Calpain inhibitor SJA6017 on albumin-mediated injury. MiR-664a-5p from albumin-treated HK-2 cells could be horizontally transported to podocytes through exosomes. Exosomes from albumin-treated HK-2 cells promoted progression of MN mice, AAV-Anti-miR-664-5p (mouse homology miRNA) could improve them. Albumin increases the miR-664a-5p level and causes changes of HIPK2/Calpain1/GSα pathway, which leads to autophagy inhibition and apoptosis up-regulation of renal tubular epithelial cells. miR-664a-5p can horizontally enter podocytes through exosomes resulting in podocytes injury. Targeted inhibition of miR-664a-5p can reduce the apoptosis of renal tubule cells and podocytes, and may improve the MN progression.

MicroRNA-483-3p Inhibitor Ameliorates Sepsis-Induced Intestinal Injury by Attenuating Cell Apoptosis and Cytotoxicity Via Regulating HIPK2

Sepsis is a life-threatening syndrome that can result in multi-organ dysfunction. MicroRNA (miR)-483-3p was previously demonstrated to be upregulated in sepsis patients; however, its specific functions in sepsis-triggered intestinal injury remain unclarified. Human intestinal epithelial NCM460 cell line was stimulated with lipopolysaccharide (LPS) to mimic sepsis-induced intestinal injury in vitro. Terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining was utilized for examining cell apoptosis. Western blotting and real time quantitative polymerase chain reaction (RT-qPCR) were used for detecting molecular protein and RNA levels. LPS-induced cytotoxicity was determined by measuring concentrations of lactate dehydrogenase (LDH), diamine oxidase (DAO) and fatty acid binding protein 2 (FABP2). Luciferase reporter assay was utilized for verifying the interaction between miR-483-3p and homeodomain interacting protein kinase 2 (HIPK2). Inhibiting miR-483-3p alleviates LPS-triggered NCM460 cell apoptosis and cytotoxicity. miR-483-3p targeted HIPK2 in LPS-stimulated NCM460 cells. Knockdown of HIPK2 reversed the above effects mediated by miR-483-3p inhibitor. Inhibiting miR-483-3p ameliorates LPS-triggered apoptosis and cytotoxicity by targeting HIPK2.

Albiflorin Alleviates Sepsis-induced Acute Liver Injury through mTOR/p70S6K Pathway

BACKGROUND

Sepsis often induces hepatic dysfunction and inflammation, accounting for a significant increase in the incidence and mortality rates. To this end, albiflorin (AF) has garnered enormous interest due to its potent anti-inflammatory activity. However, the substantial effect of AF on sepsis-mediated acute liver injury (ALI), along with its potential mechanism of action, remains to be explored.

METHODS

An LPS-mediated primary hepatocyte injury cell model in vitro and a mouse model of CLP-mediated sepsis in vivo were initially built to explore the effect of AF on sepsis. Furthermore, the hepatocyte proliferation by CCK-8 assay in vitro and animal survival analyses in vivo for the survival time of mice were carried out to determine an appropriate concentration of AF. Then, flow cytometry, Western blot (WB), and TUNEL staining analyses were performed to investigate the effect of AF on the apoptosis of hepatocytes. Moreover, the expressions of various inflammatory factors by ELISA and RT-qPCR analyses and oxidative stress by ROS, MDA, and SOD assays were determined. Finally, the potential mechanism of AF alleviating the sepsis-mediated ALI via the mTOR/p70S6K pathway was explored through WB analysis.

RESULTS

AF treatment showed a significant increase in the viability of LPS-inhibited mouse primary hepatocytes cells. Moreover, the animal survival analyses of the CLP model mice group indicated a shorter survival time than the CLP+AF group. AF-treated groups showed significantly decreased hepatocyte apoptosis, inflammatory factors, and oxidative stress. Finally, AF exerted an effect by suppressing the mTOR/p70S6K pathway.

CONCLUSION

In summary, these findings demonstrated that AF could effectively alleviate sepsis-mediated ALI via the mTOR/p70S6K signaling pathway.

Homeodomain-interacting protein kinase 2 regulates NLRP3 inflammasome activation through endoplasmic reticulum stress in septic liver injury

OBJECTIVE

Septic liver injury is a major burden for the clinical management of sepsis. Hepatocyte cell death plays a crucial pathophysiological role in sepsis. A recent study proposed that NLRP3 inflammasome-mediated pyroptosis participates in septic liver injury. Therefore, investigating the mechanism controlling this process may help manage sepsis.

METHODS

We investigated the role of homeodomain-interacting protein kinase 2 (HIPK2) in regulating the NLRP3 inflammasome in vivo using mouse models and in vitro in primary hepatocytes.

RESULTS

HIPK2 could improve liver injury and survival in a mouse model of sepsis. Overexpression of HIPK2 could suppress NLRP3 and caspase-1-p20 expression, while HIPK2 knockdown led to higher levels of these two molecules. Importantly, HIPK2 could suppress endoplasmic reticulum (ER) stress. Pharmacologically inhibiting ER stress could abolish activation of the NLRP3 inflammasome in hepatocytes with HIPK2 knockdown.

CONCLUSION

HIPK2 can regulate ER stress and NLRP3 inflammasome activation in the liver during sepsis, and HIPK2-mediated suppression of ER stress participates in regulating NLRP3 inflammasome activation. The present study highlights the role of HIPK2 in regulating the inflammasome in septic liver injury, which may serve as a target for managing sepsis.

HIPK2 in the physiology of nervous system and its implications in neurological disorders

HIPK2 is an evolutionary conserved serine/threonine kinase with multifunctional roles in stress response, embryonic development and pathological conditions, such as cancer and fibrosis. The heterogeneity of its interactors and targets makes HIPK2 activity strongly dependent on the cellular context, and allows it to modulate multiple signaling pathways, ultimately regulating cell fate and proliferation. HIPK2 is highly expressed in the central and peripheral nervous systems, and its genetic ablation causes neurological defects in mice. Moreover, HIPK2 is involved in processes, such as endoplasmic reticulum stress response and protein aggregate accumulation, and pathways, including TGF-β and BMP signaling, that are crucial in the pathogenesis of neurological disorders. Here, we review the data about the role of HIPK2 in neuronal development, survival, and homeostasis, highlighting the implications in the pathogenesis of neurological disorders, and pointing out HIPK2 potentiality as therapeutic target and diagnostic or prognostic marker.

HIPK2 as a Novel Regulator of Fibrosis

Fibrosis is an unmet medical problem due to a lack of evident biomarkers to help develop efficient targeted therapies. Fibrosis can affect almost every organ and eventually induce organ failure. Homeodomain-interacting protein kinase 2 (HIPK2) is a protein kinase that controls several molecular pathways involved in cell death and development and it has been extensively studied, mainly in the cancer biology field. Recently, a role for HIPK2 has been highlighted in tissue fibrosis. Thus, HIPK2 regulates several pro-fibrotic pathways such as Wnt/β-catenin, TGF-β and Notch involved in renal, pulmonary, liver and cardiac fibrosis. These findings suggest a wider role for HIPK2 in tissue physiopathology and highlight HIPK2 as a promising target for therapeutic purposes in fibrosis. Here, we will summarize the recent studies showing the involvement of HIPK2 as a novel regulator of fibrosis.

Fish Oil - Omega-3 Exerts Protective Effect in Oxidative Stress and Liver Dysfunctions Resulting from Experimental Sepsis

Background

Sepsis is a severe global health problem, with high morbidity and mortality. In sepsis, one of the main affected organs is the liver. Hepatic alterations characterize a negative prognostic. Omega-3 fatty acids (ω3), eicosapentaenoic acid, and docosahexaenoic acid, are part of the main families of polyunsaturated fatty acids. ω3 has been used in studies as sepsis treatment and as a treatment for non-alcoholic liver disease.

Aim

We aimed to evaluate the effects of treatment with fish oil (FO) rich in ω3 on liver changes and damage resulting from experimental sepsis.

Methodology

A model of severe sepsis in Wistar rats was used. Oxidative stress in the liver tissue was evaluated by means of tests of thiobarbituric acid reactive substances, 2,7-dihydrodichlorofluorescein diacetate , catalase, and glutathione peroxidase, in the serum TBARS, DCF, thiols and, to assess liver dysfunction, alanine aminotransferase and aspartate aminotransferase. Hepatic tissue damage was evaluated using H&E histology.

Results

In assessments of oxidative stress in liver tissue, a protective effect was observed in the tests of TBARS, DCF, CAT, and GPx, when compared the sepsis versus sepsis+ω3 groups. Regarding the oxidative stress in serum, a protective effect of treatment with ω3 was observed in the TBARS, DCF, and thiols assays, in the comparison between the sepsis and sepsis+ω3 groups. ω3 had also a beneficial effect on biochemical parameters in serum in the analysis of ALT, creatinine, urea, and lactate, observed in the comparison between the sepsis and sepsis+ω3 groups.

Conclusion

The results suggest ω3 as a liver protector during sepsis with an antioxidant effect, alleviating injuries and dysfunctions.

TSLP protects against sepsis-induced liver injury by inducing autophagy via activation of the PI3K/Akt/STAT3 pathway

BACKGROUND

Liver injury is the main factor in multiple organ failure caused by sepsis. Thymic stromal lymphopoietin (TSLP) is derived from epithelial cells and plays an important role in inflammation, allergies and cancer. The role of TSLP in sepsis-induced liver injury (SILI) is unclear. The purpose of this study was to investigate the effect of TSLP on sepsis-induced liver injury and to clarify the mechanism.

METHODS

Wild-type (WT) mice and TSLPR knockout (TSLPR^-/-) mice were subjected to cecal ligation and puncture (CLP) to generate a SILI model. Liver injury was assessed by measuring the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), histologic liver injury scores, hepatocyte death, and liver inflammatory factors. Signal pathways were explored in vivo to identify possible mechanisms for TSLP in SILI.

RESULTS

The expression of TSLP and TSLPR increased during SILI. Deletion of TSLPR exacerbated liver injury in terms of serum ALT, AST, histologic liver injury scores, and liver inflammatory factors. Compared with controls, administration of exogenous recombinant mouse TSLP reduced liver injury in WT mice during SILI, but failed to reduce liver injury in TSLPR^-/- mice. TSLP induced autophagy in hepatocytes during SILI. Mechanistically, Akt and STAT3 were activated in WT mice during SILI. The opposite results were observed in TSLPR^-/- mice. In addition, the protective effects of TSLP in WT mice were blocked by PI3K inhibitor, LY294002, during SILI.

CONCLUSION

These results suggest that TSLP can improve liver injury caused by sepsis and its specific mechanism may be related to inducing autophagy through the PI3K/Akt/STAT3 signaling pathway.

Glaucocalyxin a protect liver function via inhibiting platelet over-activation during sepsis

BACKGROUND

Rabdosia japonica (Burm. f.) var. glaucocalyx (Maxim.) is a perennial herb, and is traditionally used as folk medicine for treating inflammatory diseases and cancer. Gaucocalyxin A (GLA) is an ent‑kaurane diterpenoid that is isolated from the aerial parts of R. japonica (Burm. f.) var. glaucocalyx (Maxim.). In a recent study, we found that GLA protects against acute liver dysfunction induced by Escherichia coli, which is likely related to its anti-inflammatory effects. However, the mechanism by which GLA protects liver injury during sepsis is unknown.

AIM

To evaluate the anti-inflammatory function of GLA and its regulatory effect on platelet function.

METHOD

An in vivo model of sepsis was established by inoculating mice with E. coli. Live function and platelet activation were evaluated through standard assays. The levels of pro-inflammatory factors were measured through ELISA and qRT-PCR.

RESULTS

GLA alleviated liver dysfunction in the mouse model of sepsis. GLA-treated mice displayed lower complement activation and liver dysfunction after E. coli infection. GLA alleviated the decrease in peripheral platelet counts by inhibiting their clearance by Kupffer cells in liver. Furthermore, GLA inhibited platelet activation through the RIP1/RIP3/AKT pathway and downregulated C3aR expression on the platelets, thereby inhibiting liver injury and dysfunction due to excessive complement activation.

CONCLUSION

GLA can inhibit platelet activation by reducing surface expression of C3aR, which protect the liver from injury induced by excessive complement activation. GLA is a novel therapeutic agent for controlling sepsis-related liver dysfunction.

HIPK2 phosphorylates HDAC3 for NF-κB acetylation to ameliorate colitis-associated colorectal carcinoma and sepsis

Although inflammation is critical for the clearance of pathogens, uncontrolled inflammation also contributes to the development of multiple diseases such as cancer and sepsis. Since NF-κB-mediated transactivation in the nucleus is pivotal downstream of various stimuli to induce inflammation, searching the nuclear-localized targets specifically regulating NF-κB activation will provide important therapeutic application. Here, we have identified that homeodomain-interacting protein kinase 2 (HIPK2), a nuclear serine/threonine kinase, increases its expression in inflammatory macrophages. Importantly, HIPK2 deficiency or overexpression could enhance or inhibit inflammatory responses in LPS-stimulated macrophages, respectively. HIPK2-deficient mice were more susceptible to LPS-induced endotoxemia and CLP-induced sepsis. Adoptive transfer of Hipk2 ^+/- bone marrow cells (BMs) also aggravated AOM/DSS-induced colorectal cancer. Mechanistically, HIPK2 bound and phosphorylated histone deacetylase 3 (HDAC3) at serine 374 to inhibit its enzymatic activity, thus reducing the deacetylation of p65 at lysine 218 to suppress NF-κB activation. Notably, the HDAC3 inhibitors protected wild-type or Hipk2 ^-/- BMs-reconstituted mice from LPS-induced endotoxemia. Our findings suggest that the HIPK2-HDAC3-p65 module in macrophages restrains excessive inflammation, which may represent a new layer of therapeutic mechanism for colitis-associated colorectal cancer and sepsis.

Hepatoprotective effect of anemoside B4 against sepsis-induced acute liver injury through modulating the mTOR/p70S6K-mediated autophagy

Sepsis triggers liver dysfunction with high morbidity and mortality. Here, we elucidated the effect of anemoside B4 on sepsis in cecal ligation and puncture (CLP)-induced mouse model and LPS-induced primary hepatocytes. Following CLP surgery, septic mice were intraperitoneally injected with anemoside B4 (50 or 100 mg/kg). Anemoside B4 improved septic mouse survival rate, decreased serum AST and ALT levels and attenuated liver histopathologic damages. Western blot analysis showed that anemoside B4 elevated the expression of Beclin-1, LC3II/LC3I, Atg3, Atg5, and Atg7, and reduced p62, suggesting the restoration of autophagy flux in liver. More autophagic vesicles were observed in liver after anemoside B4 treatment using transmission electron microscopy. Using ELISA and commercial enzyme kits, we found that anemoside B4 decreased serum TNF-α, IL-6, and IL-1β levels and increased CAT, SOD and GSH activities. TUNEL staining and western blot revealed that anemoside B4 suppressed cell apoptosis, along with decreased Bax, leaved caspase-3, cleaved PARP, but increased Bcl-2. Consistent with in vivo findings, anemoside B4 inhibited apoptosis, inflammatory response, and oxidative stress and enhanced autophagy in LPS-induced primary hepatocytes. Importantly, these cellular processes were possibly mediated by mTOR/p70S6K signaling, as reflected by the offset of 3-MA in the immunosuppression of anemoside B4.

HIPK3 Mediates Inflammatory Cytokines and Oxidative Stress Markers in Monocytes in a Rat Model of Sepsis Through the JNK/c-Jun Signaling Pathway

Sepsis is a fetal immunological disorder and its complication worsens in the patients with hemodialysis which may increase the risk of death. In the present study, we aimed to investigate the effect of homeodomain-interacting protein kinase 3 (HIPK3) on inflammatory factors and oxidative stress markers in monocytes of rats with sepsis by regulating the c-Jun amino-terminal kinase (JNK)/c-Jun signaling pathway. A rat model of sepsis was initially established using cecal ligation and puncture (CLP) and was further identified by enlarged spleen tissues, inflammation, and oxidative stress. Monocytes were isolated from rats with CLP-induced sepsis. HIPK3 was observed to be downregulated while JUN was upregulated in monocytes from rats with CLP-induced sepsis. Furthermore, isolated monocytes were transduced with lentiviral vectors expressing HIPK3 or shRNA against HIPK3 to explore the effect of HIPK3 on viability and apoptosis of monocytes as well as inflammatory factors and oxidative stress markers. The obtained data exhibited that overexpression of HIPK3 or inhibition of the JNK signaling pathway enhanced proliferation, reduced apoptosis of monocytes, alleviated inflammation, and oxidative stress injury. Consistently, our results may provide evidence that HIPK3 could inhibit the JNK/c-Jun signaling pathway, thereby potentially retarding the progression of sepsis.

Knockout of calpain-1 protects against high-fat diet-induced liver dysfunction in mouse through inhibiting oxidative stress and inflammation

The present study was designed to investigate the significance of calpain-1 in the high-fat diet (HFD)-induced liver dysfunction and to explore the possible mechanism. C57 mice and calpain-1 knockout (KO) mice were fed with standard diet (SD) or HFD, respectively, for 16 weeks. The activities of calpain, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and superoxide dismutase (SOD) in serum and/or liver of mouse were measured. Lipid profiles in the serum and liver were examined. Contents of oxidized low-density lipoprotein (oxLDL), malondialdehyde (MDA), tumor necrosis factor (TNF-α), and interleukin-6 (IL-6) in serum or/and liver were detected. The results showed that compared with C57 mice fed with SD, HFD-fed C57 mice showed the increased activities of AST and ALT in the serum, which was decreased in calpain-1 KO mice fed with HFD. In addition, knockout of calpain-1 decreased the contents of oxLDL, MDA, TNF-α, and IL-6, while increased SOD activity, in serum and/or liver. However, knockout of calpain-1 had no effects on lipid profiles in both serum and liver. When fed with SD, all these parameters of C57 and calpain-1 KO mice were comparable except for decreased calpain activity in the liver of calpain-1 KO mice. The results suggested that knockout of calpain-1 protects against HFD-induced liver dysfunction through inhibiting oxidative stress and inflammation.

Sophocarpine attenuates septic liver injury through suppression of the NLRP3 inflammasome via autophagy-mediated degradation

Septic liver injury remains a challenge in sepsis treatment. Nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) inflammasome activation has been suggested to be a major cause of hepatocyte cell death in liver diseases. However, insufficient research has been performed to explore the underlying mechanisms associated with this. In the present study, sophocarpine, a pharmaceutical monomer originally isolated from Sophora flavescens, was suggested to attenuate septic liver injury in a mouse cecal ligation and puncture (CLP) model. By utilizing western blotting, ELISA, H&E staining and immunohistochemistry, the results demonstrated that sophocarpine treatment reversed CLP-induced elevations in serum aspartate transaminase, alanine transaminase, interleukin (IL)-6 and IL-1β levels. Additionally, sophocarpine appeared to have suppressed the activation of the NLRP3 inflammasome, as indicated by observed reductions in liver IL-1β, NLRP3, caspase 1-p20 and gasdermin D-p30 protein levels. Further investigation suggested that sophocarpine-induced autophagy was essential for this suppression of NLRP3 inflammasome activation, the inhibition of which reversed the protective effects of sophocarpine on CLP-induced liver injury. Collectively, results from the present study suggested a protective role for sophocarpine against septic liver injury, where sophocarpine may suppress NLRP3 inflammasome activation by autophagy-mediated degradation.

HIPK2 sustains inflammatory cytokine production by promoting endoplasmic reticulum stress in macrophages

Uncontrolled inflammatory cytokine production by macrophages contributes to numerous conditions, including infection, endotoxemia and sepsis. A previous study proposed that endoplasmic reticulum (ER) stress acts as an essential process in inflammatory cytokine production by macrophages. The present study used a mouse sepsis model and in vitro macrophages to demonstrate that homeodomain-interacting protein kinase 2 (HIPK2) sustained cytokine production in an ER stress-dependent manner. HIPK2 expression was upregulated in the early phase of lipopolysaccharide stimulation. HIPK2 knockdown attenuated IL-6 and TNF-α production, and p65 phosphorylation in macrophages. Furthermore, the attenuated cytokine production was abolished by the ER stress agonist tunicamycin. The activation of ER stress increased the levels of IL-6 and TNF-α, and the phosphorylation of p65, in macrophages following knockdown of HIPK2. Furthermore, HIPK2 inhibition attenuated the production of IL-6 and TNF-α in vitro and in vivo. Therefore, HIPK2 sustained inflammatory cytokine production by promoting ER stress in macrophages. Targeting HIPK2 may be a potential strategy for the management of uncontrolled inflammation in clinical settings.

HIPK2 Is Required for Midbody Remnant Removal Through Autophagy-Mediated Degradation

At the end of abscission, the residual midbody forms the so-called midbody remnant (MBR), a platform affecting cell fate with emerging key role in differentiation, development, and tumorigenicity. Depending on cell type and pathophysiological context, MBRs undergo different outcomes: they can be retained, released, internalized by nearby cells, or removed through autophagy-mediated degradation. Although mechanisms underlying MBR formation, positioning, and processing have been recently identified, their regulation is still largely unknown. Here, we report that the multifunctional kinase HIPK2 regulates MBR processing contributing to MBR removal. In the process of studying the role of HIPK2 in abscission, we observed that, in addition to cytokinesis failure, HIPK2 depletion leads to significant accumulation of MBRs. In particular, we detected comparable accumulation of MBRs after HIPK2 depletion or treatment with the autophagic inhibitor chloroquine. In contrast, single depletion of the two independent HIPK2 abscission targets, extrachromosomal histone H2B and severing enzyme Spastin, only marginally increased MBR retention, suggesting that MBR accumulation is not just linked to cytokinesis failure. We found that HIPK2 depletion leads to (i) increased levels of CEP55, a key effector of both midbody formation and MBR degradation; (ii) decreased levels of the selective autophagy receptors NBR1 and p62/SQSTM1; and (iii) impaired autophagic flux. These data suggest that HIPK2 contributes to MBR processing by regulating its autophagy-mediated degradation.

Exosomal miR-19a from adipose-derived stem cells suppresses differentiation of corneal keratocytes into myofibroblasts

In this study, we investigated the effects of exosomal microRNAs (miRNAs) from adipose-derived stem cells (ADSCs) on the differentiation of rabbit corneal keratocytes. Keratocytes grown in 10% FBS differentiated into myofibroblasts by increasing HIPK2 kinase levels and activity. HIPK2 enhanced p53 and Smad3 pathways in FBS-induced keratocytes. Keratocytes grown in 10% FBS also showed increased levels of pro-fibrotic proteins, including collagen III, MMP9, fibronectin, and α-SMA. These effects were reversed by knocking down HIPK2. Moreover, ADSCs and exosomes derived from ADSCs (ADSCs-Exo) suppressed FBS-induced differentiation of keratocytes into myofibroblasts by inhibiting HIPK2. Quantitative RT-PCR analysis showed that ADSCs-Exos were significantly enriched in miRNA-19a as compared to ADSCs. Targetscan and dual luciferase reporter assays confirmed that the HIPK2 3'UTR is a direct binding target of miR-19a. Keratocytes treated with 10% FBS and ADSCs-Exo-miR-19a-agomir or ADSCs-Exo-NC-antagomir showed significantly lower levels of HIPK2, phospho-Smad3, phospho-p53, collagen III, MMP9, fibronectin and α-SMA than those treated with 10% FBS plus ADSCs-Exo-NC-agomir or ADSCs-Exo-miR-19a-antagomir. Thus, exosomal miR-19a derived from the ADSCs suppresses FBS-induced differentiation of rabbit corneal keratocytes into myofibroblasts by inhibiting HIPK2 expression. This suggests their potential use in the treatment of corneal fibrosis.

Ets2 suppresses inflammatory cytokines through MAPK/NF-κB signaling and directly binds to the IL-6 promoter in macrophages

Proper activation of Toll-like receptor (TLR)-mediated signaling and production of proinflammatory cytokines are critical for the initiation of innate immunity, while the specific mechanism maintaining inflammatory homeostasis remains mostly unknown. Here, we show that Ets2 is upregulated following LPS and VSV stimulation. Ets2 knockdown or knockout leads to increased IL-6, TNF-α, and IFN-β production in macrophages. Consistently, Ets2-deficient mice show exacerbated inflammatory cytokine production and are more susceptible to CLP-induced sepsis. Mechanistically, Ets2 inhibits the LPS- and VSV-induced activation of ERK1/2, JNK, p38, and p65. Ets2 also binds to the promoter of IL-6 to inhibit transcription. Collectively, the results of the present study show the negative regulatory role of Ets2 in LPS- and VSV-induced inflammation through the suppression of MAPK/NF-κB signaling, direct binding to the IL-6 promoter and inhibition of transcription.

[Crocetin promotes autophagy in injured rat hepatocytes induced by lipopolysaccharide and D-galactosamine in vitro]

OBJECTIVE

To observe the effect of crocetin on autophagy in rat hepatocytes exposed to lipopolysaccharide (LPS) and D-galactosamine (D-gal) and explore the mechanism.

METHODS

Cultured rat hepatocytes were exposed to LPS (1 mg/L) and Dgal (60 mg/L) to induce cell injury and treated with crocetin, 3MA, or crocetin+3MA. Twelve hours after the treatments, the cells were examined for levels of ALT, AST and LDH in the supernatant using ELISA. LC3 fluorescence in the cells following immunofluorescence staining was observed using fluorescence microscopy. Autophagosomes in the cells were observed by transmission electron microscopy, and the cellular expressions of LC3, p62 and SIRT1 were detected using Western blotting.

RESULTS

The levels of ALT, AST and LDH in the hepatocytes were elevated after LPS- and D-gal-induced injury, reached the highest levels after 3MA treatment, but were decreased significantly by crocetin treatment. LC3 fluorescence increased obviously in the injured hepatoctyes, and the increment was the most obvious in crocetin-treated cells; LC3 fluorescence was decreased significantly after 3MA treatment. Cell injury induced obvious increase in autophagy in the hepatocytes, and the number of autophagosomes increased significantly after crocetin treatment but was reduced significantly after 3MA treatment. The cell injury caused an obvious up-regulation of LC3 and SIRT1 expression and down-regulated p62 expression. LC3 and SIRT1 expression levels were the highest and the expression of p62 was the lowest in cells with crocetin treatment. 3MA treatment significantly reduced the expression of LC3 and SIRT1 and increased the expression of p62 in the injured cells.

CONCLUSIONS

Autophagy is increased in injured rat hepatocytes, and crocetin can promote autophagy in the injured cells to reduce further cell injury.