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Outer membrane vesicles (OMVs) play an important role in the persistence of Helicobacter pylori infection. Helicobacter OMVs carry a plethora of virulence factors, including catalase (KatA), an antioxidant enzyme that counteracts the host respiratory burst. We found KatA to be enriched and surface-associated in OMVs compared to bacterial cells. This conferred OMV-dependent KatA activity resulting in neutralization of H2O2 and NaClO, and rescue of surrounding bacteria from oxidative damage. The antioxidant activity of OMVs was abolished by deletion of KatA. In conclusion, enrichment of antioxidative KatA in OMVs is highly important for efficient immune evasion.

ABSTRACT Bacteria shed a diverse set of outer membrane vesicles that function as transport vehicles to deliver effector molecules and virulence factors to host cells. Helicobacter pylori is a gastric pathogen that infects half of the world’s population, and in some individuals the infection progresses into peptic ulcer disease or gastric cancer. Here we report that intact vesicles from H. pylori are internalized by clathrin-dependent endocytosis and further dynamin-dependent processes, as well as in a cholesterol-sensitive manner. We analyzed the uptake of H. pylori vesicles by gastric epithelial cells using a method that we refer to as quantification of internalized substances (qIS). The qIS assay is based on a near-infrared dye with a cleavable linker that enables the specific quantification of internalized substances after exposure to reducing conditions. Both chemical inhibition and RNA interference in combination with the qIS assay showed that H. pylori vesicles enter gastric epithelial cells via both clathrin-mediated endocytosis and additional endocytic processes that are dependent on dynamin. Confocal microscopy revealed that H. pylori vesicles colocalized with clathrin and dynamin II and with markers of subsequent endosomal and lysosomal trafficking. Interestingly, however, knockdown of components required for caveolae had no significant effect on internalization and knockdown of components required for clathrin-independent carrier (CLIC) endocytosis increased internalization of H. pylori vesicles. Furthermore, uptake of vesicles by both clathrin-dependent and -independent pathways was sensitive to depletion, but not sequestering, of cholesterol in the host cell membrane suggesting that membrane fluidity influences the efficiency of H. pylori vesicle uptake. IMPORTANCE Bacterial vesicles act as long-distance tools to deliver toxins and effector molecules to host cells. Vesicles can cause a variety of host cell responses via cell surface-induced cell signaling or internalization. Vesicles of diverse bacterial species enter host cells via different endocytic pathways or via membrane fusion. With the combination of a fluorescence-based quantification assay that quantifies internalized vesicles in a large number of cells and either chemical inhibition or RNA interference, we show that clathrin-mediated endocytosis is the major pathway for uptake of Helicobacter pylori vesicles and that lipid microdomains of the host cell membrane affect uptake of vesicles via clathrin-independent pathways. Our results provide important insights about membrane fluidity and its important role in the complex process that directs the H. pylori vesicle to a specific endocytic pathway. Understanding the mechanisms that operate in vesicle-host interactions is important to fully recognize the impact of vesicles in pathogenesis.

Background & Aim: Aju Mbaise is a polyherbal extract with nutraceutical properties that helps to replenish the volume of blood lost during childbirth and improves breast milk secretion and the general wellbeing of the mother. This study evaluated the ameliorative potentials of Aju Mbaise extract (AME) on Dutasteride-induced oxidative stress and hepatic injury in rats. Twenty-one rats were used to assess the acute toxicity of AME. Experimental: The study for the hepatoprotective effects of AME had five groups of rats, including normal control, Dutasteride only, AME only, Dutasteride + AME (500 mg/kg) and Dutasteride+ AME (1000 mg/kg). Results: The acute toxicity result showed that AME is relatively safe for consumption. Dutasteride caused significant elevation of liver marker enzymes, including aspartate transaminase (AST), alanine transaminase (ALT), transaminase (AST), alkaline phosphatase (ALP), total bilirubin, malondialdehyde (MDA) and significantly reduced catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH), total proteins, albumin, and globulin levels in the rats received only Dutasteride. In contrast, Dutasteride induced rats treated with AME showed a significant decline in the AST, ALT, ALP, MDA, and bilirubin and significantly increased SOD, GSH, GPx, total proteins, albumin, and globulin levels compared to Dutasteride induced untreated rats. The AME-treated rats showed normal liver histo-architecture, unlike the Dutasteride-induced untreated rats that showed mild to moderate vacuolar degeneration of the hepatocytes. Recommended applications/industries: The findings show that AME ameliorates Dutasteride caused rats oxidative stress and hepatic injury.

This study investigated the therapeutic effect of a combined extract of Spermacoce radiata and Hypselodelphys poggeana (CESH) on oxidative markers and haematological parameters in benign prostatic hyperplasia (BPH) induced rats. The study adopted five groups containing equal numbers of rats (n = 6), including normal control, BPH control, Finasteride control, BPH-induced rats treated with 200 mg/kg CESH, and BPH-induced rats treated with 600 mg/kg CESH. The rats were induced BPH by the subcutaneous administration of a 5 mg/kg testosterone propionate injection. At the same time, treatment finasteride and CESH to the respective groups were given orally 60 minutes after the BPH induction for 28 uninterrupted days. The induction of BPH with testosterone propionate injection caused a significant reduction in the serum levels of haematological parameters, including haemoglobin (Hb), packed cell volume (PCV), red blood cells (RBC), and platelet counts of the BPH control compared with normal control. The glutathione (GSH) concentration, glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione S-transferase, and catalase activities decreased significantly in the BPH control relative to the normal control. The BPH control had elevated white blood cell (WBC), and malondialdehyde (MDA) concentrations contrary to the high WBC and MDA in the normal control and CESH treated BPH induced rats, respectively. Conversely, the Hb, PCV, platelet count, GPx, SOD, catalase, GST, and GSH increased significantly in the finasteride and CESH-treated BPH-induced rats, respectively, compared to the BPH control. These findings show that CESH attenuates adverse effects of BPH on antioxidant parameters and oxidative markers, which may prevent BPH progression.

Benign prostatic hyperplasia (BPH) is a urological disease prevalent among the ageing male population, which impairs the quality of life, including hyperlipidaemia and a decline in renal functions. Combining Anthocleista vogelii and Alstonia boonei stem bark extract has effectively managed BPH and its associated complications. This study evaluated the effects of a combined Anthocleista vogelii and Alstonia boonei stem bark extract (CAASBE) on the lipid profile and renal functions of rats induced benign prostatic hyperplasia with testosterone propionate injection. The study comprised five treatment groups, with groups 1 – 5 being the normal control, BPH control, standard control, BPH+200 mg/kg CAASBE, and BPH+400 mg/kg CAASBE, respectively. BPH was induced in the groups 2 – 4 rats by subcutaneous administration of testosterone propionate injection (5 mg/kg) for 28 days, and treatment with Finasteride and CAASBE were administered orally. The BPH control rats exhibited a significant (p < 0.05) increase in the total serum cholesterol, triacylglycerol (TAG), low-density lipoprotein cholesterol (LDL-C), urea, creatinine and significant (p < 0.05) decline in the serum high-density lipoprotein cholesterol (HDL-C) compared to the normal control. Conversely, treatment of the BPH rats with 200 and 400 mg/kg of CAASBE significantly (p < 0.05) reversed the altered total serum cholesterol, TAG, LDL-C, HDL-C, urea and creatinine to normal levels comparable to that of the normal control and standard control respectively. These findings show that CAASBE alleviates hyperlipidaemia and renal malfunctions in the BPH rats suggesting it could be effective in managing BPH complication.

Background and Aim: Aju Mbaise is a nutraceutical food supplement taken by nursing mothers within their first three months of delivery due to its health advantages. This study evaluated the protective potentials of Aju Mbaise extract on the renal functions, lipid profile, and haematological indices of Dutasteride-induced rats. Materials and Methods: This study had sham control, dutasteride control, an extract group that received 1000 mg/kg of Aju Mbaise only, and Dutasteride induced groups treated with 500 and 1000 mg/kg of Aju Mbaise orally for 28 consecutive days. Results: Dutasteride induction caused a remarkable increase in the serum urea, creatinine, sodium, potassium, and chloride ions and a considerable reduction in the serum bicarbonate ions in the Dutasteride control compared to the sham control. The lipid profile indicated a significant increase in the total serum cholesterol, triacylglycerol, low-density lipoprotein cholesterol, and very low-density lipoprotein cholesterol, along with a substantial decline in the serum high-density lipoprotein cholesterol of the Dutasteride control relative to the sham control. The haematological parameters, including red blood cell, packed cell volume, haemoglobin, mean corpuscular haemoglobin concentration, and neutrophils, decreased significantly in the Dutasteride control relative to the sham control. In contrast, the Dutasteride control showed a significant increase in the mean corpuscular volume, white blood cell, platelet, and lymphocyte counts compared to the sham control. The treatment of Dutasteride-induced rats with 500 and 1000 mg/kg of Aju Mbaise extract significantly restored the serum urea, creatinine, serum electrolytes, lipid profile, and haematological parameters to normal levels compared to the Dutasteride control. None the rats had any observable alteration in the kidney histo-architecture. Conclusion: Our findings showed that Aju Mbaise extract could attenuate changes in renal functions, lipid profile, and haematological indices associated with Dutasteride toxicity in rats.