DUSP5 (dual-specificity protein phosphatase 5) suppresses BCG-induced autophagy via ERK 1/2 signaling pathway

LncRNA PART1 Attenuates Myocardial Ischemia-Reperfusion Injury by Regulating TFAP2C/DUSP5 Axis via miR-302a-3p

BACKGROUND AND OBJECTIVES

Myocardial ischemia-reperfusion injury (MIRI) refers to the damage of cardiac function caused by restoration of blood flow perfusion in ischemic myocardium. However, long non-coding RNA prostate androgen regulated transcript 1 (PART1)'s role in MIRI remain unclear.

METHODS

Immunofluorescence detected LC3 expression. Intermolecular relationships were verified by dual luciferase reporter assay. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry and transferase-mediated dUTP nick-end labeling (TUNEL) assays analyzed cell viability and apoptosis. The release of lactate dehydrogenase was tested via enzyme-linked immunosorbent assay (ELISA). Left anterior descending coronary artery surgery induced a MIRI mouse model. Infarct area was detected by 2,3,5-triphenyltetrazolium chloride staining. Hematoxylin and eosin staining examined myocardial injury. ELISA evaluated myocardial marker (creatine kinase MB) level.

RESULTS

PART1 was decreased in hypoxia/reoxygenation (H/R) induced AC16 cells and MIRI mice. PART1 upregulation attenuated the increased levels of Bax, beclin-1 and the ratio of LC3II/I, and enhanced the decrease of Bcl-2 and p62 expression in H/R-treated cells. PART1 upregulation alleviated H/R-triggered autophagy and apoptosis via miR-302a-3p. Mechanically, PART1 targeted miR-302a-3p to upregulate transcription factor activating enhancer-binding protein 2C (TFAP2C). TFAP2C silencing reversed the protected effects of miR-302a-3p inhibitor on H/R treated AC16 cells. We further established TFAP2C combined to dual-specificity phosphatase 5 (DUSP5) promoter and activated DUSP5. TFAP2C upregulation suppressed H/R-stimulated autophagy and apoptosis through upregulating DUSP5. Overexpressed PART1 reduced myocardial infarction area and attenuated MIRI in mice.

CONCLUSION

PART1 improved the autophagy and apoptosis in H/R-exposed AC16 cells through miR-302a-3p/TFAP2C/DUSP5 axis, which might provide novel targets for MIRI treatment.

Dual-specificity phosphatase 5-mediated fatty acid oxidation promotes Mycobacterium bovis BCG -induced inflammatory responses

Mycobacterium tuberculosis (Mtb) reprograms FAs metabolism of macrophages during infection and affects inflammatory reaction eventually, however, the mechanism remains poorly understood. Here we show that Mycobacterium bovis (BCG) induces DUSP5 expression through TLR2-MAPKs signaling pathway and promotes fatty acid oxidation (FAO). Silencing DUSP5 by adeno-associated virus vector (AAV) ameliorates lung injury and DUSP5 knockdown reduces the expression of IL-1β, IL-6 and inactivated NF-κB signaling in BCG-infected macrophages. Of note, DUSP5 specific siRNA increases the content of free fatty acids (FFAs) and triglyceride (TG), but represses the expression of FAO associated enzymes such as CPT1A and PPARα, suggesting DUSP5 mediated FAO during BCG infection. Moreover, Inhibiting FAO by pharmacological manner suppresses IL-1β, IL-6, TNF-α expression and relieves lung damage. Taken together, our data indicates DUSP5 mediates FAO reprogramming and promotes inflammatory response to BCG infection.

A novel trypsin of Trichinella spiralis mediates larval invasion of gut epithelium via binding to PAR2 and activating ERK1/2 pathway

BACKGROUND

Proteases secreted by Trichinella spiralis intestinal infective larvae (IIL) play an important role in larval invasion and pathogenesis. However, the mechanism through which proteases mediate larval invasion of intestinal epithelial cells (IECs) remains unclear. A novel T. spiralis trypsin (TsTryp) was identified in IIL excretory/secretory (ES) proteins. It was an early and highly expressed protease at IIL stage, and had the potential as an early diagnostic antigen. The aim of this study was to investigate the biological characteristics of this novel TsTryp, its role in larval invasion of gut epithelium, and the mechanisms involved.

METHODOLOGY/PRINCIPAL FINDING

TsTryp with C-terminal domain was cloned and expressed in Escherichia coli BL21 (DE3), and the rTsTryp had the enzymatic activity of natural trypsin, but it could not directly degrade gut tight junctions (TJs) proteins. qPCR and western blotting showed that TsTryp was highly expressed at the invasive IIL stage. Immunofluorescence assay (IFA), ELISA and Far Western blotting revealed that rTsTryp specifically bound to IECs, and confocal microscopy showed that the binding of rTsTryp with IECs was mainly localized in the cytomembrane. Co-immunoprecipitation (Co-IP) confirmed that rTsTryp bound to protease activated receptors 2 (PAR2) in Caco-2 cells. rTsTryp binding to PAR2 resulted in decreased expression levels of ZO-1 and occludin and increased paracellular permeability in Caco-2 monolayers by activating the extracellular regulated protein kinases 1/2 (ERK1/2) pathway. rTsTryp decreased TJs expression and increased epithelial permeability, which could be abrogated by the PAR2 antagonist AZ3451 and ERK1/2 inhibitor PD98059. rTsTryp facilitated larval invasion of IECs, and anti-rTsTryp antibodies inhibited invasion. Both inhibitors impeded larval invasion and alleviated intestinal inflammation in vitro and in vivo.

CONCLUSIONS

TsTryp binding to PAR2 activated the ERK1/2 pathway, decreased the expression of gut TJs proteins, disrupted epithelial integrity and barrier function, and consequently mediated larval invasion of the gut mucosa. Therefore, rTsTryp could be regarded as a potential vaccine target for blocking T. spiralis invasion and infection.

A novel Trichinella spiralis serine proteinase disrupted gut epithelial barrier and mediated larval invasion through binding to RACK1 and activating MAPK/ERK1/2 pathway

BACKGROUND

Gut epithelium is the first natural barrier against Trichinella spiralis larval invasion, but the mechanism by which larval penetration of gut epithelium is not completely elucidated. Previous studies showed that proteases secreted by T. spiralis intestinal infective larvae (IIL) degraded tight junctions (TJs) proteins of gut epithelium and mediated larval invasion. A new T. spiralis serine proteinase (TsSPc) was identified in the IIL surface proteins and ES proteins, rTsSPc bound to the intestinal epithelial cell (IECs) and promoted larval invasion of IECs. The aim of this study was to characterize the interacted proteins of TsSPc and IECs, and to investigate the molecular mechanisms of TsSPc mediating larval invasion of gut mucosa.

METHODOLOGY/PRINCIPAL FINDING

IIFT results showed natural TsSPc was detected in infected murine intestine at 6, 12 hours post infection (hpi) and 3 dpi. The results of GST pull-down, mass spectrometry (MS) and Co-IP indicated that rTsSPc bound and interacted specifically with receptor for activated protein C kinase 1 (RACK1) in Caco-2 cells. rTsSPc did not directly hydrolyze the TJs proteins. qPCR and Western blot showed that rTsSPc up-regulated RACK1 expression, activated MAPK/ERK1/2 pathway, reduced the expression levels of gut TJs (occludin and claudin-1) and adherent protein E-cad, increased the paracellular permeability and damaged the integrity of intestinal epithelial barrier. Moreover, the RACK1 inhibitor HO and ERK1/2 pathway inhibitor PD98059 abolished the rTsSPc activating ERK1/2 pathway, they also inhibited and abrogated the rTsSPc down-regulating expression of occludin, claudin-1 and E-cad in Caco-2 monolayer and infected murine intestine, impeded larval invasion and improved intestinal epithelial integrity and barrier function, reduced intestinal worm burdens and alleviated intestinal inflammation.

CONCLUSIONS

rTsSPc bound to RACK1 receptor in gut epithelium, activated MAPK/ERK1/2 pathway, decreased the expression of gut epithelial TJs proteins and disrupted the epithelial integrity, consequently mediated T. spiralis larval invasion of gut epithelium. The results are valuable to understand T. spiralis invasion mechanism, and TsSPc might be regarded as a vaccine target against T. spiralis invasion and infection.

The Role of Epinephelus coioides DUSP5 in Regulating Singapore Grouper Iridovirus Infection

The dual-specificity phosphatase (DUSP) family plays an important role in response to adverse external factors. In this study, the DUSP5 from Epinephelus coioides, an important marine fish in Southeast Asia and China, was isolated and characterized. As expected, E. coioides DUSP5 contained four conserved domains: a rhodanese homology domain (RHOD); a dual-specificity phosphatase catalytic domain (DSPc); and two regions of low compositional complexity, indicating that E. coioides DUSP5 belongs to the DUSP family. E. coioides DUSP5 mRNA could be detected in all of the examined tissues, and was mainly distributed in the nucleus. Infection with Singapore grouper iridovirus (SGIV), one of the most important pathogens of marine fish, could inhibit the expression of E. coioides DUSP5. The overexpression of DUSP5 could significantly downregulate the expression of the key SGIV genes (MCP, ICP18, VP19, and LITAF), viral titers, the activity of NF-κB and AP-I, and the expression of pro-inflammatory factors (IL-6, IL-8, and TNF-α) of E. coioides, but could upregulate the expressions of caspase3 and p53, as well as SGIV-induced apoptosis. The results demonstrate that E. coioides DUSP5 could inhibit SGIV infection by regulating E. coioides immune-related factors, indicating that DUSP5 might be involved in viral infection.

S100A4 Promotes BCG-Induced Pyroptosis of Macrophages by Activating the NF-κB/NLRP3 Inflammasome Signaling Pathway

Pyroptosis is a host immune strategy to defend against Mycobacterium tuberculosis (Mtb) infection. S100A4, a calcium-binding protein that plays an important role in promoting cancer progression as well as the pathophysiological development of various non-tumor diseases, has not been explored in Mtb-infected hosts. In this study, transcriptome analysis of the peripheral blood of patients with pulmonary tuberculosis (PTB) revealed that S100A4 and GSDMD were significantly up-regulated in PTB patients' peripheral blood. Furthermore, there was a positive correlation between the expression of GSDMD and S100A4. KEGG pathway enrichment analysis showed that differentially expressed genes between PTB patients and healthy controls were significantly related to inflammation, such as the NOD-like receptor signaling pathway and NF-κB signaling pathway. To investigate the regulatory effects of S100A4 on macrophage pyroptosis, THP-1 macrophages infected with Bacillus Calmette-Guérin (BCG) were pre-treated with exogenous S100A4, S100A4 inhibitor or si-S100A4. This research study has shown that S100A4 promotes the pyroptosis of THP-1 macrophages caused by BCG infection and activates NLRP3 inflammasome and NF-κB signaling pathways, which can be inhibited by knockdown or inhibition of S100A4. In addition, inhibition of NF-κB or NLRP3 blocks the promotion effect of S100A4 on BCG-induced pyroptosis of THP-1 macrophages. In conclusion, S100A4 activates the NF-κB/NLRP3 inflammasome signaling pathway to promote macrophage pyroptosis induced by Mtb infection. These data provide new insights into how S100A4 affects Mtb-induced macrophage pyroptosis.

Mmu-miR-25-3p promotes macrophage autophagy by targeting DUSP10 to reduce mycobacteria survival

Background

The present study aimed to investigate the regulation of miR-25-3p on macrophage autophagy and its effect on macrophage clearance of intracellular Mycobacterium bovis Bacillus Calmette-Guerin (BCG) retention based on the previous findings on the differential expression of exosomal miRNA in macrophages infected with BCG.

Methods

Through enrichment analysis and Hub gene analysis, key differentially expressed miRNA and its target genes were selected. The targeted binding ability of the screened mmu-miR-25-3p and its predicted target gene DUSP10 was determined through the TargetScan database, and this was further verified by dual luciferase reporter gene assay. mmu-miR-25-3p mimics, mmu-miR-25-3p inhibitor, si-DUSP10, miR-NC,si-NC and PD98059 (ERK Inhibitor) were used to intervene macrophages Raw264.7. Rt-qPCR was used to detect the expression levels of mmu-miR-25-3p and DUSP10 mRNA. Western blot was used to detect the expression levels of DUSP10, LC3-II, p-ERK1/2, beclin1, Atg5 and Atg7. The autophagy flux of macrophage Raw264.7 in each group was observed by confocal laser microscopy, and the expression distribution of DUSP10 and the structure of autophagosomes were observed by transmission electron microscopy. Finally, the intracellular BCG load of macrophage Raw264.7 was evaluated by colony-forming unit (CFU) assay.

Results

Bioinformatics analysis filtered and identified the differentially expressed exosomal miRNAs. As a result, mmu-miR-25-3p expression was significantly increased, and dual specificity phosphatase 10 (DUSP10) was predicted as its target gene that was predominantly involved in autophagy regulation. The dual luciferase reporter gene activity assay showed that mmu-miR-25-3p was targeted to the 3'-untranslated region (UTR) of DUSP10. The infection of BCG induced the upregulation of mmu-miR-25-3p and downregulation of DUSP10 in RAW264.7 cells, which further increased the expression of LC3-II and promoted autophagy. Upregulated mmu-miR-25-3p expression decreased the level of DUSP10 and enhanced the phosphorylation of ERK1/2, which in turn upregulated the expression of LC3-II, Atg5, Atg7, and Beclin1. Immuno-electron microscopy, transmission electron microscopy, and autophagic flux analysis further confirmed that the upregulation of mmu-miR-25-3p promotes the autophagy of macrophages after BCG infection. The CFU number indicated that upregulated mmu-miR-25-3p expression decreased the mycobacterial load and accelerated residual mycobacteria clearance.

Conclusion

mmu-miR-25-3p promotes the phosphorylation of ERK1/2 by inhibiting the expression of DUSP10, thus enhancing the BCG-induced autophagy of macrophages. These phenomena reduce the bacterial load of intracellular Mycobacterium and facilitate the clearance of residual mycobacteria. mmu-miR-25-3p has great potential as a target for anti-tuberculosis immunotherapy and can be the optimal miRNA loaded into exosomal drug delivery system in future studies.

Targeting Autophagy Using Long Non-Coding RNAs (LncRNAs): New Landscapes in the Arena of Cancer Therapeutics

Cancer has become a global health hazard accounting for 10 million deaths in the year 2020. Although different treatment approaches have increased patient overall survival, treatment for advanced stages still suffers from poor clinical outcomes. The ever-increasing prevalence of cancer has led to a reanalysis of cellular and molecular events in the hope to identify and develop a cure for this multigenic disease. Autophagy, an evolutionary conserved catabolic process, eliminates protein aggregates and damaged organelles to maintain cellular homeostasis. Accumulating evidence has implicated the deregulation of autophagic pathways to be associated with various hallmarks of cancer. Autophagy exhibits both tumor-promoting and suppressive effects based on the tumor stage and grades. Majorly, it maintains the cancer microenvironment homeostasis by promoting viability and nutrient recycling under hypoxic and nutrient-deprived conditions. Recent investigations have discovered long non-coding RNAs (lncRNAs) as master regulators of autophagic gene expression. lncRNAs, by sequestering autophagy-related microRNAs, have been known to modulate various hallmarks of cancer, such as survival, proliferation, EMT, migration, invasion, angiogenesis, and metastasis. This review delineates the mechanistic role of various lncRNAs involved in modulating autophagy and their related proteins in different cancers.

BAF53A drives colorectal cancer development by regulating DUSP5-mediated ERK phosphorylation

BAF53A, an important subunit of the SWI/SNF epigenetic chromatin regulatory complex, has been implicated as the driver of diverse cancers. However, the role of BAF53A in colorectal cancer (CRC) remains poorly understood. Here, we examined the expression of BAF53A in CRC samples and observed that BAF53A was significantly upregulated in CRC tissues compared with paired adjacent normal tissues. In vitro and in vivo studies suggested that ectopic expression of BAF53A promoted colorectal cancer cell proliferation, colony formation, and tumorigenesis, whereas knockdown of BAF53A hindered these cellular functions. DUSP5 (dual-specificity phosphatase 5), an ERK1/2-specific endogenous phosphatase, was expressed at low levels in CRC. We found a negative correlation between BAF53A and DUSP5 expression in a set of CRC samples. Mechanistic studies revealed that P63 was a potential transcription repressor of DUSP5. BAF53A could interact with P63, decreasing the DUSP5 expression level and subsequently promoting ERK1/2 phosphorylation. Thus, our study provides insights into the applicability of the BAF53A-DUSP5-ERK1/2 axis as a potential therapeutic target in CRC.

Effect of Autolyzed Yarrowia lipolytica on the Growth Performance, Antioxidant Capacity, Intestinal Histology, Microbiota, and Transcriptome Profile of Juvenile Largemouth Bass (Micropterus salmoides)

The improper components of formulated feed can cause the intestinal dysbiosis of juvenile largemouth bass and further affect fish health. A 28 day feeding trial was conducted to investigate the effect of partially replacing fish meal (FM) with autolyzed Yarrowia lipolytica (YL) on juvenile largemouth bass (Micropterus salmoides). We considered four diets—control, YL25, YL50, and YL75—in which 0%, 25%, 50%, and 75% of the FM content, respectively, was replaced with YL. According to results, the weight gain rate (WGR) and specific growth rate (SGR) of the fish with the YL25 and YL50 diets were significantly higher than the WGR and SGR with the control diet, while the YL75 diet significantly reduced fish growth and antioxidant enzymes activities, and shortened the villus height in the intestinal mucosa. The 16S rRNA analysis of the intestinal microbiota showed that the relative abundance of Mycoplasma was significantly increased with the YL25 and YL50 diets, while the Enterobacteriacea content was increased with the YL75 diet. Moreover, our transcriptome analysis revealed that certain differentially expressed genes (DEGs) that are associated with growth, metabolism, and immunity were modulated by YL inclusion treatment. Dietary YL25 and YL50 significantly reduced the mRNA level of ERBB receptor feedback inhibitor 1 (errfi1) and dual-specificity phosphatases (dusp), while the expression of the suppressor of cytokine signaling 1 (socs1), the transporter associated with antigen processing 2 subunit type a (tap2a), and the major histocompatibility complex class I-related gene (MHC-I-l) were sharply increased with YL75 treatment. We determined that the optimum dose of dietary YL required for maximum growth without any adverse influence on intestinal health was 189.82 g/kg (with 31.63% of the fishmeal replaced by YL), while an excessive substitution of YL for fishmeal led to suppressed growth and antioxidant capacity, as well as intestinal damage for juvenile largemouth bass.

Screening of genes encoding proteins that interact with ISG15: Probing a cDNA library from a snakehead fish cell line using a yeast two-hybrid system

Interferon-stimulated gene 15 (ISG15) regulates cellular life processes, including defense responses against infection by a variety of viral pathogens, by binding to target proteins. At present, various fish ISG15s have been identified, but the biological function of ISG15 in snakehead fish is still unclear. In this study, total RNA was extracted from snakehead fish cell line E11, ds cDNA was synthesized and purified using SMART technology, and the resulting cDNA library was screened by co-transforming yeast cells. The library titer was 4.28 × 10⁹ CFU/mL. Using snakehead ISG15 as the bait protein, the recombinant bait vector pGBKT7-ISG15 was constructed and transformed into the yeast strain Y2HGold. The toxicity and self-activation activity of the bait vector were detected on the deficient medium, and the prey proteins interacting with ISG15 were screened. In total, 19 interacting proteins of ISG15 were identified, including mitotic checkpoint protein BUB3, hypothetical protein SnRVgp6, elongation factor 1-beta, 60S ribosomal protein L9, dual specificity protein phosphatase 5-like, eukaryotic translation initiation factor 3 subunit I and ferritin. A yeast spotting assay further probed the interaction between ISG15 and DUSP5. These results increase our understanding of the interaction network of snakehead ISG15 and will aid in exploring the underlying mechanisms of snakehead ISG15 functions in the future.

Human Papillomavirus Type 16 Early Protein E7 Activates Autophagy through Inhibition of Dual-Specificity Phosphatase 5

Consistent high-risk human papillomavirus (HPV) infection leads to various malignant cancers. Autophagy can promote cancer progression by helping cancer cells survive under stress or induce oncogenic effects when mutations or abnormalities occur. Mitogen activated protein kinases (MAPKs) can transduce various external or intrinsic stimuli into cellular responses, including autophagy, and dual-specificity phosphates (DUSPs) contribute to the direct regulation of MAPK activities. Previously, we showed that expression of DUSP5 was repressed in HPV16 E7-expressing normal human epidermal keratinocytes (NHEKs). Here we show that clinical HPV16 E7-positive precancerous and cancerous tissues also demonstrate low DUSP5 levels compared with control tissues, indicating that the inverse correlation between HPV16 E7 and DUSP5 is clinically relevant. We furthermore investigated the autophagy response in both DUSP5-deficient and HPV16 E7-expressing NHEKs. Confocal microscopy and Western analysis showed induction of LC3-II levels, autophagosome formation and autophagy fluxes in DUSP5-deficient NHEKs. Furthermore, Western analysis demonstrated specific induction of phosphorylated ERK in DUSP5-deficient and HPV16 E7-expressing NHEKs, indicating that HPV16 E7-mediated repression of DUSP5 results in induced MAPK/ERK signaling. Finally, phosphorylated mTOR and ULK (S757) were reduced in DUSP5-deficient NHEKs, while phosphorylated ULK (S555) and AMPK were increased, thereby inducing canonical autophagy through the mTOR and AMPK pathways. In conclusion, our results demonstrate that HPV16 E7 expression reduces DUSP5 levels, which in turn results in active MAPK/ERK signaling and induction of canonical autophagy through mTOR and MAPK regulation. Given its demonstrated inverse correlation with clinical cancerous tissues, DUSP5 may serve as a potential therapeutic target for cervical cancer.