Biology subjects

Hou, X.

Publications and source records attributed to Hou, X..

7 recordsLinked to original sources

bioRxiv2026

Nuclear Cathepsin L Remodels the Replication Machinery to Create a Therapeutic Vulnerability in Ovarian Cancer

Abstract Therapeutic resistance in ovarian cancer is frequently driven by persistent replication stress, yet the molecular mechanisms that convert replication stress into a therapeutically exploitable vulnerability remain incompletely understood. Here, we identify drug-induced nuclear cathepsin L (nCTSL) as a previously unrecognized regulator of replication stress and DNA repair. Clofarabine (CLF) combined with the ATR inhibitor AZD6738, or the CHK1 inhibitor prexasertib promoted nuclear accumulation of CTSL, where it remodeled the replication machinery through degradation of CCNE1, MCM3, MCM6, and geminin, accompanied by loss of RAD51 and 53BP1 and increased {gamma}H2AX and phospho-RPA2. DNA fiber analysis demonstrated marked inhibition of replication fork progression following CLF-based combinations, whereas CTSL depletion accelerated fork progression and abolished therapy-induced replication stress. Reconstitution with the nuclear M1F CTSL isoform restored replication restraint, confirming a direct role for nuclear CTSL in regulating replication dynamics. GFP-based DNA repair reporter assays further revealed that CLF-based combinations suppress DNA repair competence in a CTSL-dependent manner, indicating that nuclear CTSL couples replication stress amplification with functional inhibition of repair pathways. Functionally, CLF-based combinations selectively targeted transformed fallopian tube secretory epithelial cells while sparing non-transformed counterparts, demonstrated broad activity in patient-derived ovarian cancer ascites spheroids, and significantly inhibited tumor growth and prolonged survival in vivo. Collectively, our findings identify nuclear CTSL as a mechanistic driver of replication stress that remodels the replication machinery, impairs DNA repair, and creates a therapeutically exploitable vulnerability in ovarian cancer. We propose that nuclear CTSL promotes a transition from replication competence to replication catastrophe, thereby establishing a conceptual framework for biomarker-guided therapeutic strategies targeting CTSL-dependent replication stress.

cancer biology↗

bioRxiv2018

Differential gene expression, including Sjfs800, in Schistosoma japonicum females before, during, and after male-female pairing

Schistosomiasis is a prevalent but neglected tropical disease caused by parasitic trematodes of the genus Schistosoma, with the primary disease-causing species being S. haematobium, S. mansoni, and S. japonicum. Male-female pairing of schistosomes is necessary for sexual maturity and the production of a large number of eggs, which are primarily responsible for schistosomiasis dissemination and pathology. Here, we used microarray hybridization, bioinformatics, quantitative PCR, in situ hybridization, and gene silencing assays to identify genes that play critical roles in S. japonicum reproduction biology, particularly in vitellarium development, a process that affects male-female pairing, sexual maturation, and subsequent egg production. Microarray hybridization analyses generated a comprehensive set of genes differentially transcribed before and after male-female pairing. Although the transcript profiles of females were similar 16 and 18 days after host infection, marked gene expression changes were observed at 24 days. The 30 most abundantly transcribed genes on day 24 included those associated with vitellarium development. Among these, genes for female-specific 800 (fs800), eggshell precursor protein, and superoxide dismutase (cu-zn-SOD) were substantially upregulated. Our in situ hybridization results in female S. japonicum indicated that cu-zn-SOD mRNA was highest in the ovary and vitellarium, eggshell precursor protein mRNA was expressed in the ovary, ootype, and vitellarium, and Sjfs800 mRNA was observed only in the vitellarium, localized in mature vitelline cells. Knocking down the Sjfs800 gene in female S. japonicum by approximately 60% reduced the number of mature vitelline cells, decreased rates of pairing and oviposition, and decreased the number of eggs produced in each male-female pairing by about 50%. These results indicate that Sjfs800 is essential for vitellarium development and egg production in S. japonicum and suggest that Sjfs800 regulation may provide a novel approach for the prevention or treatment of schistosomiasis.\n\nAuthor SummarySchistosomiasis is a common but largely unstudied tropical disease caused by parasitic trematodes of the genus Schistosoma. The eggs of schistosomes are responsible for schistosomiasis transmission and pathology, and the production of these eggs is dependent on the pairing of females and males. In this study, we determined which genes in Schistosoma japonicum females were differentially expressed before and after pairing with males, identifying the 30 most abundantly expressed of these genes. Among these 30 genes, we further characterized those in female S. japonicum that were upregulated after pairing and that were related to reproduction and vitellarium development, a process that affects male-female pairing, sexual maturation, and subsequent egg production. We identified three such genes, S. japonicum female-specific 800 (Sjfs800), eggshell precursor protein, and superoxide dismutase, and confirmed that the mRNAs for these genes were primarily localized in reproductive structures. By using gene silencing techniques to reduce the amount of Sjfs800 mRNA in females by about 60%, we determined that Sjfs800 plays a key role in development of the vitellarium and egg production. This finding suggests that regulation of Sjfs800 may provide a novel approach to reduce egg counts and thus aid in the prevention or treatment of schistosomiasis.

genomics↗

bioRxiv2018

Tissue-expression profiles unveils the gene interaction of hepatopancreas, eyestalk, and ovary in precocious female Chinese mitten crab, Eriocheir sinensis

Sexual precocity is a serious and common biological phenomenon in animal species. Large amount of precocity individuals was identified in Chinese mitten crab, Eriocheir sinensis, which caused huge economical loss every year. However, the underlying genetic basis of precocity in E. sinensis is still lack. In this study, histology observation, comparative transcriptome was conducted among different stages of precocious one-year old and normal two-year old E. sinensis, tissue-expression profiles of ovary, hepatopancreas, and eyestalk tissues were presented and compared. Genes associated with lipid metabolic process, lipid transport, vitelline membrane formation, vitelline synthesis and neuropeptide hormone related genes were upregulated in the ovary, hepatopancreas and eyestalk of precocious E. sinensis. Our results indicated eyestalk involved in neuroendocrine system providing neuropeptide hormone that may induce vitellogenesis in hepatopancreas and further stimulate ovary development. Hepatopancreas is a site for energy storage, vitellogenin synthesis and may assist to induce oogenesis through lipid transport in precocious E. sinensis. The genetic basis of precocity in E. sinensis is an integrated gene regulatory network of eyestalk, hepatopancreas, and ovary tissues. Our study provides effective convenient phenotype measurement method for identification of potential precocious E. sinensis detection, and valuable genetic resources and novel insights into the research of molecular mechanism of precocity in E. sinensis.

bioinformatics↗

bioRxiv2018

B1a cells protect against Schistosoma japonicum-induced liver inflammation and fibrosis by controlling monocyte infiltration

During Schistosoma infection, lack of B cells results in more severe granulomas, inflammation, and fibrosis in the liver, but the mechanisms underlying this pathology remain unclear. Thus, our aim was to clarify the mechanisms underpinning the immunomodulation of B cells in mice infected with Schistosoma japonicum. We found that B cell deficiency led to aggravated liver pathology, as demonstrated by increases in the size of the egg-associated granulomas, alanine transaminase levels, and collagen deposition. Compared with infected wild-type mice, infected B cell-deficient MT mice showed increased infiltration of Ly6Chi monocytes and higher levels of proinflammatory cytokines (tumor necrosis factor alpha, interleukin 6, and interleukin 12) and chemokines ([C-C motif] ligands (CCL)2, CCL3, CCL4, and CCL5). The results of flow cytometric analysis and cell transfer experiments showed that B1a cells increased significantly in the liver following S. japonicum infection, with some of those cells deriving from the peritoneal cavity. We also found that secretion of IL-10 from hepatic B cells increased significantly in infected wild-type mice and that this IL-10 was mainly derived from B1a cells. In addition, adoptively transferring peritoneal cavity B cells purified from wild-type, but not from IL-10-deficient mice, to MT mice significantly reduced liver pathology and liver infiltration of Ly6Chi monocytes. These reductions were accompanied by decreases in the expression levels of chemokines and inflammatory cytokines. Taken together, these data indicated that after S. japonicum infection, an increased number of hepatic B1a cells secrete IL-10, which inhibits the expression of chemokines and cytokines and suppresses the infiltration of Ly6Chi monocytes into the liver thereby alleviating liver early inflammation and late fibrosis. Understanding this immunomodulatory role of B1a cells in schistosomiasis may lead to the development of therapeutic strategies for Schistosoma-induced liver disease.\n\nAuthor summaryInfection with Schistosoma, a waterborne parasitic flatworm (trematode) commonly called a blood fluke, results in strong granulomatous inflammation caused by the deposition of eggs in the liver. A granuloma is a substantial immune cell infiltration around the eggs intermixed with liver cells that can protect the host against liver damage. However, excessive infiltration and inflammation can lead to severe liver injury and fibrosis. Here, we found that B1a cells accumulate in the liver of mice after S. japonicum-induced infection and that these B1a cells release the anti-inflammatory cytokine interleukin 10 to regulate inflammation. The B1a cell-derived interleukin 10 inhibits the expression of chemokines (which attract cells such as monocytes to sites of infection or inflammation) and thus restrains excessive infiltration of Ly6Chi monocytes (which may have proinflammatory activity) into the liver, thereby alleviating early inflammation and later fibrosis. Our study provides insight into the immunomodulation of B1a cells in schistosomiasis and offers key information for the development of therapeutic strategies in Schistosoma-induced liver disease.

immunology↗

bioRxiv2018

Yes-associated protein (YAP) is required in maintaining normal ovarian follicle development and function

Yes-associated protein (YAP) is one of the major components of the Hippo signaling pathway, also known as the Salvador/Warts/Hippo (SWH) pathway. Although the exact extracellular signal that controls the Hippo pathway is currently unknown, increasing evidence supports a critical role of the Hippo pathway in embryonic development, regulation of organ size, and carcinogenesis. The ovary is one of few adult tissues that exhibit cyclical changes. Ovarian follicles, the basic units of ovary, are composed of a single oocyte surrounded by expanding layers of granulosa and theca cells. Granulosa cells (GCs) produce sex steroids and growth factors, which facilitate the development of the follicle and maturation of the oocyte. It has been reported that YAP is highly expressed in human GC tumors, but the role of YAP in normal ovarian follicle development is largely unknown. In current study, we examined YAP expression in bovine ovaries. We demonstrate that downstream hippo signaling effector protein, YAP and transcription co-activator, TAZ, are present and localization of both YAP and TAZ are density-dependent. Likewise, YAP and TAZ are critically involved in granulosa cell proliferation. Furthermore, reducing YAP in granulosa cells inhibits FSH-induced aromatase expression and estradiol biosynthesis. The data suggest that YAP plays an important role in the development of ovarian follicles and estradiol synthesis, which are necessary for maintaining normal ovarian function.

cell biology↗

bioRxiv2018

Apigenin relaxes rat intrarenal arteries: involvement of Cl- channels and K+ channels

The vasodilator effect of apigenin (API) was demonstrated in a number of vascular beds. We aimed to characterize the vasospasmolytic and electrophysiological effects of apigenin (API) in intrarenal arteries (IRAs). The vascular tone of male rat isolated IRAs was recorded with a myograph. Transmembrane Cl- currents through Ca2+-activated Cl- channels (CaCCs), K+ currents through voltage-gated K+ (Kv) channels and inwardly rectifier K+ (Kir) channels were recorded with patch clamp in the freshly isolated arterial smooth muscle cells (ASMCs). Preincubation with API (10-100 M) concentration-dependently depressed the contractions induced by KCl, 9,11-dideoxy-9,11-methanoepoxy prostaglandin F2 (U46619), phenylephrine and vasopressin without significant preference and the IC50 values were 13.27-26.26 M. Acute application of API elicited instant relaxations in the IRAs precontracted with these vasoconstrictors and the RC50 values were 5.80-24.33 M. API relaxation was attenuated by chloride deprivation, CaCC blockers, Kv blocker and nitric oxide synthase inhibitor, but not by Kir blocker and cyclooxygenase inhibitor. At 10-100 M, API depressed CaCC currents and Kir currents while enhanced Kv currents of IRA ASMCs. The present results demonstrate that API counteracts various vasoconstrictors noncompetitively and nonspecifically and suggest that modulation of CaCCs, Kv and Kir channels of IRA ASMCs is involved in its vasospasmolytic effects.

pharmacology and toxicology↗

bioRxiv2018

Structures reveal opening of the store-operated calcium channel Orai

The store-operated calcium (Ca2+) channel Orai governs Ca2+ influx through the plasma membrane of many non-excitable cells in metazoans. The channel opens in response to depletion of Ca2+ within the endoplasmic reticulum (ER). Loss- and gain-of-function mutants of Orai cause disease. Our previous work revealed the structure of Orai with a closed pore. Here, using a gain-of-function mutation that constitutively activates the channel, we present an X-ray structure of Drosophila melanogaster Orai in an open conformation. Well-defined electron density maps reveal that the open pore is dramatically dilated on its cytosolic side in comparison to the slender closed pore. Cations and anions bind in different regions of the open pore, informing mechanisms for ion permeation and the exquisite selectivity of the channel for Ca2+. Opening of the pore requires the release of cytosolic latches. Together with additional X-ray structures of an unlatched-but-closed intermediate, we propose a sequence for store-operated activation.

biochemistry↗