Cryptosporidium parvum hijacks a host's long noncoding RNA U90926 to evade intestinal epithelial cell-autonomous antiparasitic defense.

Cryptosporidium is a zoonotic apicomplexan parasite that infects the gastrointestinal epithelium and other mucosal surfaces in humans. It is an important opportunistic pathogen in AIDS patients and a leading cause of infectious diarrhea and diarrheal-related death in children worldwide. The intestinal epithelial cells provide the first line of defense against Cryptosporidium infection and play a central role in activating and regulating the host's antiparasitic response. Increasing evidence suggests that long noncoding RNAs (lncRNAs) participate in host-pathogen interactions and play a regulatory role in the pathogenesis of diseases but the underlying molecular mechanisms are not fully understood. We previously identified a panel of host lncRNAs that are upregulated in murine intestinal epithelial cells following Cryptosporidium infection, including U90926. We demonstrate here that U90926 is acting in a pro-parasitic manner in regulating intestinal epithelial cell-autonomous antiparasitic defense. Inhibition of U90926 resulted in a decreased infection burden of the parasite while overexpression of U90926 showed an increase in infection burden in cultured murine intestinal epithelial cells. Induction of U90926 suppressed transcription of epithelial defense genes involved in controlling Cryptosporidium infection through epigenetic mechanisms. Specifically, transcription of Aebp1, which encodes the Aebp1 protein, a potent modulator of inflammation and NF-κB signaling, was suppressed by U90926. Gain- or loss-of-function of Aebp1 in the host's epithelial cells caused reciprocal alterations in the infection burden of the parasite. Interestingly, Cryptosporidium carries the Cryptosporidium virus 1 (CSpV1), a double-stranded (ds) RNA virus coding two dsRNA fragments, CSpV1-dsRdRp and CSpV1-dsCA. Both CSpV1-dsRdRp and CSpV1-dsCA can be delivered into infected cells as previously reported. We found that cells transfected with in vitro transcribed CSpV1-dsCA or CSpV1-dsRdRp displayed an increased level of U90926, suggesting that CSpV1 is involved in the upregulation of U90926 during Cryptosporidium infection. Our study highlights a new strategy by Cryptosporidium to hijack a host lncRNA to suppress epithelial cell-autonomous antiparasitic defense and allow for a robust infection.

A host cell long noncoding RNA NR_033736 regulates type I interferon-mediated gene transcription and modulates intestinal epithelial anti-Cryptosporidium defense.

The gastrointestinal epithelium guides the immune system to differentiate between commensal and pathogenic microbiota, which relies on intimate links with the type I IFN signal pathway. Epithelial cells along the epithelium provide the front line of host defense against pathogen infection in the gastrointestinal tract. Increasing evidence supports the regulatory potential of long noncoding RNAs (lncRNAs) in immune defense but their role in regulating intestinal epithelial antimicrobial responses is still unclear. Cryptosporidium, a protozoan parasite that infects intestinal epithelial cells, is an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children in developing countries. Recent advances in Cryptosporidium research have revealed a strong type I IFN response in infected intestinal epithelial cells. We previously identified a panel of host cell lncRNAs that are upregulated in murine intestinal epithelial cells following microbial challenge. One of these lncRNAs, NR_033736, is upregulated in intestinal epithelial cells following Cryptosporidium infection and displays a significant suppressive effect on type I IFN-controlled gene transcription in infected host cells. NR_033736 can be assembled into the ISGF3 complex and suppresses type I IFN-mediated gene transcription. Interestingly, upregulation of NR_033736 itself is triggered by the type I IFN signaling. Moreover, NR_033736 modulates epithelial anti-Cryptosporidium defense. Our data suggest that upregulation of NR_033736 provides negative feedback regulation of type I IFN signaling through suppression of type I IFN-controlled gene transcription, and consequently, contributing to fine-tuning of epithelial innate defense against microbial infection.

Ferulic acid attenuates oxidative DNA damage and inflammatory responses in microglia induced by benzo(a)pyrene.

Over-activation of microglia disrupts the physiological homeostasis of the brain, and induces inflammatory response and other processes which are implicated in neurodegenerative diseases. Therefore, theoretically, suppression of neuroinflammation would slow the progression of neurodegenerative disease. In this study, we investigated the possible protective effects of Ferulic acid (FA) against benzo(a)pyrene (BaP)-induced microglial activation using BV2 cells as the model system. Exposure of BV2 cells to BaP (10 µM) significantly increased DNA damage and the production of pro-inflammatory mediators, including nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), reactive oxygen species (ROS), malondialdehyde (MDA), and cytokines (interleukins-1ß and -6). On the other hand, when BaP-treated BV2 cells were further incubated with FA (10, 20, 40, or 80 mg/mL) for another 24 h, a significant reduction in BaP-induced DNA damage and the release of multiple pro-inflammatory and cytotoxic factors (including interleukin-1ß, interleukin-6, NO, and ROS) was observed in a dose-dependent manner. Further study revealed that the microglial NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) signaling pathway was involved in the protective effect of FA. Taken together, these results suggested that FA suppressed BaP-induced toxicity in microglia, and thus may exert neuroprotective effects by inhibiting microglia-mediated pro-inflammatory response.

MiR-28-5p relieves neuropathic pain by targeting Zeb1 in CCI rat models.

MicroRNAs (miRNAs) are recognized as significant regulators of neuropathic pain. Moreover, neuroinflammation can contribute a lot to the progression of neuropathic pain. MiR-28-5p has been reported to be involved in many pathological diseases. However, little is known about the function of miR-28-5p in neuropathic pain development. Our current study was designed to investigate the biological roles of miR-28-5p in neuropathic pain in a rat model established by chronic sciatic nerve injury (CCI). Here, we observed that miR-28-5p was decreased in CCI rats. MiR-28-5p overexpression was able to alleviate neuropathic pain behaviors including mechanical and thermal hyperalgesia. Meanwhile, inflammation-correlated biomarkers such as Cyclooxygenase 2 (Cox-2), interleukin-6 (IL-6), and IL-1ß were greatly promoted in CCI rats and they were inhibited by miR-28-5p upregulation. In addition, zinc finger E-box-binding homeobox 1 (Zeb1) is a kind of transcription factor that is involved in various diseases. Here, in our study, Zeb1 was predicted as a downstream target of miR-28-5p. miR-28-5p can bind with the 3'-untranslated region of Zeb1, which was validated by carrying out dual-luciferase reporter assay. Moreover, we found that Zeb1 was significantly increased in CCI rats and miR-28-5p can modulate Zeb1 expression negatively. Theoverexpression of Zeb1 can disturb neuropathic pain development, which was repressed by the increase of miR-28-5p by upregulating Cox-2, IL-6, and IL-1ß levels. By taking all of these together, it was indicated in our study that miR-28-5p can reduce neuropathic pain progression by targeting Zeb1 in vivo. Our data implied that miR-28-5p/Zeb1 axis can be a novel therapeutic target for neuropathic pain treatment.

Mycoepoxydiene suppresses HeLa cell growth by inhibiting glycolysis and the pentose phosphate pathway.

Upregulation of glycolysis and the pentose phosphate pathway (PPP) is a major characteristic of the metabolic reprogramming of cancer and provides cancer cells with energy and vital metabolites to support their rapid proliferation. Targeting glycolysis and the PPP has emerged as a promising antitumor therapeutic strategy. Marine natural products are attractive sources for anticancer therapeutics, as evidenced by the antitumor drug Yondelis. Mycoepoxydiene (MED) is a natural product isolated from a marine fungus that has shown promising inhibitory efficacy against HeLa cells in vitro. We used a proteomic approach with two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry to explore the cellular targets of MED and to unravel the molecular mechanisms underlying the antitumor activity of MED in HeLa cells. Our proteomic data showed that triosephosphate isomerase (TPI) and 6-phosphogluconolactonase (PGLS), which participate in glycolysis and the PPP, respectively, were significantly downregulated by MED treatment. Functional studies revealed that the expression levels of several other enzymes involved in glycolysis and the PPP, including hexokinase 2 (HK2), phosphofructokinase 1 (PFKM), aldolase A (ALDOA), enolase 1 (ENO1), lactate dehydrogenase A (LDHA), and glucose-6-phosphate dehydrogenase (G6PD), were also reduced in a dose-dependent manner. Moreover, the LDHA and G6PD enzymatic activities in HeLa cells were inhibited by MED, and overexpression of these downregulated enzymes rescued HeLa cells from the growth inhibition induced by MED. Our data suggest that MED suppresses HeLa cell growth by inhibiting glycolysis and the PPP, which provides a mechanistic basis for the development of new therapeutics against cervical cancer.