Pyroptosis Tuning in Intestinal Cryptosporidiosis via the Natural Histone Deacetylase Inhibitor Romidepsin.

Cryptosporidium is an opportunistic protozoan, with many species of cross-human infectivity. It causes life-threatening diarrhoea in children and CD4-defective patients. Despite its limited efficacy, nitazoxanide remains the primary anti-cryptosporidial drug. Cryptosporidium infects the intestinal brush border (intracellular-extracytoplasmic) and down-regulates pyroptosis to prevent expulsion. Romidepsin is a natural histone deacetylase inhibitor that triggers pyroptosis. Romidepsin's effect on cryptosporidiosis was assessed in immunocompromised mice via gasdermin-D (GSDM-D) immunohistochemical expression, IFN-γ, IL-1ß and IL-18 blood levels by ELISA, and via parasite scanning by modified Ziehl-Neelsen staining and scanning electron microscopy (SEM). Oocyst deformity and local cytokines were also assessed in ex vivo ileal explants. Following intraperitoneal injection of romidepsin, oocyst shedding significantly reduced at the 9th, 12th and 15th d.p.i. compared with infected-control and drug-control (nitazoxanide-treated) mice. H&E staining of intestinal sections from romidepsin-treated mice showed significantly low intestinal scoring with marked reduction in epithelial hyperplasia, villous blunting and cellular infiltrate. SEM revealed marked oocyst blebbing and paucity (in vivo and ex vivo) after romidepsin compared with nitazoxanide. Regarding pyroptosis, romidepsin triggered significantly higher intestinal GSDM-D expression in vivo, and higher serum/culture IFN-γ, IL-1ß and IL-18 levels in romidepsin-treated mice than in the control groups. Collectively, in cryptosporidiosis, romidepsin succeeded in enhancing pyroptosis in the oocysts and infected epithelium, reducing infection and shifting the brush border towards normalisation.

Stem cell-derived exosomes as a potential therapy for schistosomal hepatic fibrosis in experimental animals.

Schistosomiasis is a neglected tropical disease. Egg-induced granuloma formation and tissue fibrosis are the main causes of the high morbidity and mortality of schistosomiasis. Mesenchymal stem cells (MSCs)-derived exosomes play an important role with a superior safety profile than MSCs in the treatment of liver fibrosis. Therefore, the aim of this study was to investigate the potential therapeutic effect of MSCs-derived exosomes on schistosomal hepatic fibrosis. Exosomes were isolated from bone marrow MSCs and characterized. A total of 85 mice were divided into four groups: group I (control group), group II (PZQ group) infected and treated with PZQ, group III (EXO group) infected and treated with MSCs-derived exosomes and group IV (PZQ+EXO group) infected and treated with both PZQ and MSCs-derived exosomes. Assessment of treatment efficacy was evaluated by histopathological and immunohistochemical examination of liver sections by proliferating cell nuclear antigen (PCNA) and nuclear factor-κB (NF-κB). The results showed significant reduction of the number and diameter of hepatic granulomas, hepatic fibrosis, upregulation of PCNA expression and reduction of NF-κB expression in EXO and PZQ+EXO groups as compared to other groups at all durations post infection. Additionally, more improvement was observed in PZQ+EXO group. In conclusion, MSCs-derived exosomes are a promising agent for the treatment of schistosomal hepatic fibrosis, and their combination with PZQ shows a synergistic action including antifibrotic and anti-inflammatory effects. However, further studies are required to establish their functional components and their mechanisms of action.

Artesunate effect on schistosome thioredoxin glutathione reductase and cytochrome c peroxidase as new molecular targets in schistosoma mansoni-infected mice.

OBJECTIVE: To investigate the possible effect of artesunate (ART) on schistosome thioredoxin glutathione reductase (TGR) and cytochrome c peroxidase (CcP) in Schistosoma mansoni-infected mice. METHODS: A total of 200 laboratory bred male Swiss albino mice were divided into 4 groups (50 mice in each group). Group I: infected untreated group (Control group) received a vehicle of 1% sodium carbonyl methylcellulose (CMC-Na); Group II: infected then treated with artesunate; Group III: infected then treated with praziquantel, and group IV: infected then treated with artesunate then praziquantel. Adult S. mansoni worms were collected by Animal Perfusion Method, tissue egg counted, TGR, and CcP mRNA Expression were estimated of in S. mansoni adult worms by semi-quantitative rt-PCR. RESULTS: Semi-quantitative rt-PCR values revealed that treatment with artesunate caused significant decrease in expression of schistosome TGR and CcP in comparison to the untreated group. In contrast, the treatment with praziquantel did not cause significant change in expression of these genes. The results showed more reduction in total worm and female worm count in combined ART-PZQ treated group than in monotherapy treated groups by either ART or PZQ. Moreover, complete disappearance (100%) of tissue eggs was recorded in ART-PZQ treated group with a respective reduction rate of 95.9% and 68.4% in ART- and PZQ-treated groups. CONCLUSION: The current study elucidated for the first time that anti-schistosomal mechanisms of artesunate is mediated via reduction in expression of schistosome TGR and CcP. Linking these findings, addition of artesunate to praziquantel could achieve complete cure outcome in treatment of schistosomiasis.

Congenital exposure to Schistosoma mansoni infection: impact on the future immune response and the disease outcome.

Schistosomiasis mansoni is a widespread parasitic infection that may lead to several serious complications, such as hepatic periportal fibrosis and portal hypertension, mainly due to deposition of schistosome eggs in the tissues. However, people in endemic areas infrequently exhibit severe pathology and complications; this may be explained, in part, by modulation of the disease in indigenous populations by in utero exposure to the parasite. This study investigated the differences between mice born to Schistosoma mansoni-infected mothers and those born to non-infected ones in subsequent postnatal schistosomal infections. We found that the intensity of infection, evidenced by hepatic egg load, was much reduced in mice born to infected mothers. No difference was found as regards total and Schistosoma-specific immunoglobulin levels except for total IgG. The levels of gene expression of two regulatory cytokines, namely interleukin-12 (IL-12) and transforming growth factor beta (TGF-beta) were found to be significantly increased in prenatally exposed animals. Moreover, liver fibrosis was significantly decreased in animals born to infected mothers as revealed by histopathological and histochemical examination as well as by immunohistochemical identification of activated hepatic stellate cells (HSCs) using antibody against glial fibrillary acidic protein (GFAP). In conclusion, congenital exposure to S. mansoni seems to ameliorate the immunopathological changes in future postnatal infections.

Central role of IL-10 as key regulator of inflammation during intestinal trichinellosis in mice.

This study characterized some immuno-pathological aspects of intestinal trichinellosis where, the influence of this nematode infection on levels of IL-10 mRNA expression, nitric oxide (NO) and myeloperoxidase (MPO) in intestinal mucosa is going to be studied. Four groups of albino mice were infected orally by Trichinella spiralis (T. spiralis) larvae and sacrificed on days 3, 6, 14, & 30 post infections (d.p.i.). Levels of the previously mentioned parameters were measured in the infected intestinal tissue samples and compared to non-infected normal controls. The results showed gradual increase of IL-10 mRNA expression at 3 d.p.i., to reach its peak levels at 14 d.p.i. The mucosal levels of NO and MPO showed sharp increased by 3rd d.p.i., with a peak on 6 d.p.i. These biochemical changes were in accordance with the pathological changes observed by histopathological examination of stained small intestinal sections. The data reinforce the concept of the central role played by IL-10, as a Th2 cytokine in controlling severe inflammatory process initiated by NO under the influence of this invading parasite.

Experimental schistosomal hepatitis: protective effect of coenzyme-Q10 against the state of oxidative stress.

Schistosoma mansoni (S. mansoni) eggs trapped in the host liver elicit a chain of oxidative processes that may be, at least in part, responsible for the pathology and progression of fibrosis associated with schistosomal hepatitis. This study was designed to assess the protective effect of the antioxidant coenzyme-Q10 (Co-Q10) against experimental S. mansoni-induced oxidative stress in the liver, and its potential role as an adjuvant to praziquantel (PZQ) therapy. The oxidative stress and overall liver function were improved under Co-Q10 therapy as evidenced by significant reduction in oxidative stress markers and preservation of antioxidant factors. Liver fibrosis was also reduced with a positive impact on liver function. Moreover, addition of Co-Q10 to PZQ therapy caused: significant reduction of liver egg load, significant improvement of the redox status, and lastly decreased liver fibrosis.

Potential effect of Curcuma longa extract on infectivity and pathogenicity of Schistosoma mansoni cercariae.

Batch of freshly shed cercariae from infected laboratory bred Biomphalaria alexandrina were exposed to different sub-lethal concentrations of turmeric extract for an hour and divided into two groups. The first one was to study the ultrastructural changes induced in them using scanning electron microscopy (SEM). The second group was to study infectivity and pathogenicity of the exposed cercariae. One hundred and fifty mice were divided into 5 groups: GI: Infected by normal cercariae and served as controls; GII, GIII, GIV & GV infected by cercariae exposed to 2.5, 5, 7.5 & 10 ppm, respectively. Ten weeks post infection all animals were sacrificed and subjected to parasitologic, histopathologic and immunologic assays. SEM showed cercariae exposed to 5 ppm with minimal destruction of head spines and tail. The degenerative changes were progressively severe by increasing extract concentration to reach complete destruction of both at 10 ppm. Infectivity decreased with the increase in concentration to reach highest significance at 10 ppm. Pathogenicity or mean number of egg deposited, mean diameter of liver granulomas and level of IL-10 gene expression significantly decreased in Gs IV & V.

Effect of organochlorine (DDT) exposure on experimental giardiasis.

This work studied the effect of sub-chronic DDT exposure on the course of experimental giardiasis and efficacy of its treatment. A total of 160 mice were divided into six groups: G1: 30 mice received DDT and infected with Giardia lamblia. G2: 30 mice received DDT, infected and treated with tinidazole (TNZ). G3: 30 mice infected with Giardia. G4: 30 mice infected and treated with TNZ. G5: 30 mice received DDT only. G6: 10 mice served as normal control. Mice were sacrificed at 7, 14, 21 & 28 days P.I. All groups were subjected to cyst count/2 hours collected stool, trophozoite count in intestine, histopathological examination of small intestinal section and avidin biotin peroxidase technique for local IgA staining. Also, IFN-gamma was measured in sera. DDT caused early shedding of many cysts and increase in trophozoite counts for a long time, decreased intra epithelial lymphocytes, low levels of IgA & IFN-gamma and severe histopathological changes in intestinal sections in G1 as compared to G3. Also, DDT reduced the efficacy of TNZ treatment in G2 as compared to G4. The results strongly support the immunomodulating effect of DDT on experimental giardiasis that might be responsible for persistence of infection, resistance to treatment and re-infection in DDT exposed persons.