Yorkie Negatively Regulates the Expression of Antimicrobial Proteins by Inducing Cactus Transcription in Prawns Macrobrachium nipponense

Acute hypoxia stress mediates HIF-1α-Yki-Cactus axis to facilitate the infection of Vibrio parahaemolyticus in Litopenaeus vannamei

Introduction

Hypoxia stress renders aquatic animals more susceptible to bacterial disease, yet the underlying mechanism remains elusive.

Methods

We conducted an acute hypoxia stress experiment to investigate the impact of stress on the immune response of Litopenaeus vannamei via transcriptome analysis, RT-qPCR and Western blot.

Results

Our results showed that acute hypoxia stress disrupted the tissue architecture, and significantly changed the gene expression profiles in the hepatopancreas of shrimp. More importantly, acute hypoxia stress significantly changed the expression levels of immune-related genes. Ladderlectin, GBP 1, Caspase-1, CLEC4F, MR1 and GBP 2 were significantly down-regulated, but HIF-1α, Cactus, TIPE, Akirin-2, Ivns1abp and TLR3 were significantly up-regulated. We further demonstrated that acute hypoxia activated Yki via HIF-1α to enhance expression level of Cactus, and then Cactus inhibited the phosphorylation of Dorsal and its nuclear translocation, thereby suppressing antibacterial immunity. Subsequently, the challenge experiment following stress revealed that exposure to acute hypoxia stress amplified the infectivity and lethality of Vibrio parahaemolyticus to shrimp. The mechanism of HIF-1α-Yki-Cautus axis provided an explanation for this phenomenon.

Discussion

This study offered new insights into interactions among environmental hypoxia stress, host immunity and pathogens, thereby providing practical guidelines for optimizing shrimp culture practices.

PacBio single-molecule long-read sequencing provides new insights into the complexity of full-length transcripts in oriental river prawn, macrobrachium nipponense

BACKGROUND

Oriental river prawn (Macrobrachium nipponense) is one of the most dominant species in shrimp farming in China, which is a rich source of protein and contributes to a significant impact on the quality of human life. Thus, more complete and accurate annotation of gene models are important for the breeding research of oriental river prawn.

RESULTS

A full-length transcriptome of oriental river prawn muscle was obtained using the PacBio Sequel platform. Then, 37.99 Gb of subreads were sequenced, including 584,498 circular consensus sequences, among which 512,216 were full length non-chimeric sequences. After Illumina-based correction of long PacBio reads, 6,599 error-corrected isoforms were identified. Transcriptome structural analysis revealed 2,263 and 2,555 alternative splicing (AS) events and alternative polyadenylation (APA) sites, respectively. In total, 620 novel genes (NGs), 197 putative transcription factors (TFs), and 291 novel long non-coding RNAs (lncRNAs) were identified.

CONCLUSIONS

In summary, this study offers novel insights into the transcriptome complexity and diversity of this prawn species, and provides valuable information for understanding the genomic structure and improving the draft genome annotation of oriental river prawn.

White Spot Syndrome Virus (WSSV) Inhibits Hippo Signaling and Activates Yki To Promote Its Infection in Penaeus vannamei

White spot syndrome virus (WSSV) is a serious threat to shrimp aquaculture, especially Pacific white shrimp, Penaeus vannamei, the most farmed shrimp in the world. Activation of the Hippo-Yki signaling pathway, characterized by the intracellular Hippo-Wts kinase cascade reactions and the phosphorylation and cytoplasmic retention of Yki, is widely involved in various life activities. The current work established the fundamental structure and signal transduction profile of the Hippo-Yki pathway in P. vannamei and further investigated its role in viral infection. We demonstrated that WSSV promoted the dephosphorylation and nuclear translocation of Yki, suggesting that Hippo signaling is impaired and Yki is activated after WSSV infection in shrimp. In vivo, Yki gene silencing suppressed WSSV infection, while Hippo and Wts silencing promoted it, indicating a positive role of Hippo signaling in antiviral response. Further analyses showed that Yki suppressed Dorsal pathway activation and inhibited hemocyte apoptosis in WSSV-infected shrimp, while Hippo and Wts showed opposite effects, which contributed to the role of Hippo signaling in WSSV infection. Therefore, the current study suggests that WSSV annexes Yki to favor its infection in shrimp by inhibiting Hippo signaling. IMPORTANCE White spot syndrome virus (WSSV) is one of the most harmful viral pathogens to shrimp. The pathological mechanism of WSSV infection remains unclear to date. The Hippo-Yki signaling pathway is important for various biological processes and is extensively involved in mammalian immunity, but little is known about its role in infectious diseases in invertebrates. Based on revealing the fundamental structure of the shrimp Hippo pathway, this study investigated its implication in the pathogenesis of WSSV disease. We demonstrated that WSSV enhanced Yki activation by inhibiting Hippo signaling in shrimp. The activated Yki promoted WSSV infection by inhibiting hemocyte apoptosis and suppressing the activation of Dorsal, an NF-κB family member in shrimp that is critical for regulating antiviral response. Therefore, this study suggests that WSSV can hijack the Hippo-Yki signaling pathway to favor its infection in shrimp.

Effect of cell density on the malignant biological behavior of breast cancer by altering the subcellular localization of ANXA2 and its clinical implications

OBJECTIVE

To investigate the subcellular localization of ANXA2 in breast cancer of different cell densities in humans and its relationship with the clinicopathological features of patients. To investigate the differences in ANXA2 subcellular localization in MDA-MB-231 cells of different cell densities. To compare the proliferation, invasion, and migration ability of MDA-MB-231 cells under different ANXA2 subcellular localization.

METHODS

Immunohistochemistry was applied to detect the subcellular localization of ANXA2 in tissue sections of 60 breast cancer patients, and the association with ANXA2 subcellular localization was verified in conjunction with cell density. To investigate the relationship between cell density and clinicopathological data of breast cancer patients. To establish high- and low-density models of MDA-MB-231 breast cancer cell lines and verify the subcellular localization of ANXA2 using immunofluorescence and observation under confocal microscopy. The proliferation, migration, and invasion ability of MDA-MB-231 cells under different subcellular localization of ANXA2 were detected and compared using CCK-8 assay and Transwell assay. After changing the subcellular localization of ANXA2 in high-density MDA-MB-231 cells with PY-60, changes in biological behaviors of the compared MDA-MB-231 cells were observed. Two different 4T1 cell lines with high and low densities were implanted subcutaneously in nude mice to observe the effects of different cell densities on tumor growth in nude mice.

RESULTS

The clinical data showed that breast cancer with high cell density had higher T stage and higher TNM stage, and the cell density was positively correlated with breast cancer mass size. ANXA2 was mainly localized to the cell membrane when the cell density of breast cancer cells was high and to the cytoplasm when the cell density was low. The CCK-8 assay showed that the proliferation rate of MDA-MB-231 cells increased (P < 0.05) after shifting the subcellular localization of ANXA2 from the cell membrane to the cytoplasm. Transwell invasion assay and Transwell migration assay showed that the invasion and migration ability of MDA-MB-231 cells increased significantly after the subcellular localization of ANXA2 was transferred from the cell membrane to the cytoplasm (P < 0.05). The animal experiments showed that high-density breast cancer cells could promote the growth of subcutaneous tumors in nude mice relative to low-density breast cancer cells.

CONCLUSION

Cell density can regulate the subcellular localization of ANXA2, and changes in the subcellular localization of ANXA2 are accompanied by the changes in the biological behavior of breast cancer.

Immune function analysis of LsSd, a transcription factor of the Hippo signaling pathway, in the cigarette beetle Lasioderma serricorne

The Scalloped (Sd) is a transcription factor that regulates organ size control in the Hippo-signaling pathway. Recent studies have showed that Hippo signaling also functions in the innate immune response. Although the Sd gene has been reported in many insects, their immune functions remain unexplored. In this study, the LsSd gene of Lasioderma serricorne, with a complete open reading frame that encodes a protein composed of 402 amino acids was identified. LsSd was predominantly expressed in early pupae. Tissue-specific analyses revealed that the highest concentrations of LsSd were detected in the midgut and brain. At 1–24 h after Escherichia coli infection, LsSd expression increased substantially. However, LsSd expression was downregulated 3–12 h after Staphylococcus aureus infection. RNA interference-mediated silencing of the LsSd transcript resulted in deformed, considerably smaller, and degenerated wings. Meanwhile, LsCycE, LsDiap1, and LsVg, which are involved in cell proliferation and wing development, were drastically reduced when LsSd was depleted. In a survival assay, the LsSd knockdown considerably decreased the susceptibility to S. aureus, a gram-positive bacterium. In addition, knockdown of LsSd remarkably downregulated the transcription of LsCact in response to S. aureus stimulation, while upregulating the expression of five immune-related genes. Our results provide conclusive proof for the important roles of LsSd in the immune response of L. serricorne.