Hemolysin Co-Regulatory Protein 1 Enhances the Virulence of Clinically Isolated Escherichia coli in KM Mice by Increasing Inflammation and Inducing Pyroptosis

Abstract

Hemolysin-coregulated protein 1 (Hcp1) is an effector released by the type VI secretion system (T6SS) in certain pathogenic strains of Escherichia coli (E. coli) that causes apoptosis and contributes to the development of meningitis. The exact toxic consequences of Hcp1 and whether it intensifies the inflammatory response by triggering pyroptosis are yet unknown. Here, utilizing the CRISPR/Cas9 genome editing method, we removed the gene expressing Hcp1 from wild-type E. coli W24 and examined the impact of Hcp1 on E. coli virulence in Kunming (KM) mice. It was found that Hcp1-sufficient E. coli was more lethal, exacerbating acute liver injury (ALI) and acute kidney injury (AKI) or even systemic infections, structural organ damage, and inflammatory factor infiltration. These symptoms were alleviated in mice infected with W24Δhcp1. Additionally, we investigated the molecular mechanism by which Hcp1 worsens AKI and found that pyroptosis is involved, manifested as DNA breaks in many renal tubular epithelial cells. Genes or proteins closely related to pyroptosis are abundantly expressed in the kidney. Most importantly, Hcp1 promotes the activation of the NLRP3 inflammasome and the expression of active caspase-1, thereby cleaving GSDMD-N and accelerating the release of active IL-1β and ultimately leading to pyroptosis. In conclusion, Hcp1 enhances the virulence of E. coli, aggravates ALI and AKI, and promotes the inflammatory response; moreover, Hcp1-induced pyroptosis is one of the molecular mechanisms of AKI.

Anti-Hcp1 Monoclonal Antibody Is Protective against Burkholderia pseudomallei Infection via Recognizing Amino Acids at Asp95-Leu114

“…Hcp, essential for assembling a functional T6SS, facilitates the injection of T6SS substrates by chaperoning the substrates [38]. Hcp1, a member of the Hcp protein family, is crucial in the infection processes of various bacteria, such as E. coli and Aeromonas hydrophila [39,40]. The structure of Hcp1, comprising nine β-sheets and one α-helix forming a hexameric ring, is fundamental to its function.…”

Pyroptosis: The Determinator of Cell Death and Fate in Acute Kidney Injury

“…Gentamicin-Induced AKI Hemolysin co-regulatory protein 1 (HCP1) motivates the expression of active caspase-1 and the activation of the NLRP3 inflammasome, which leads to the cleavage of GSDMD-N, an increase in the release of active IL-1β, and ultimately pyroptosis [81]. There was an increase in the expression of pyroptosis-related markers and pyroptosis-induced cell death in gentamicin (GM)-induced AKI.…”

“…Doxorubicin was administered to rats as a single intraperitoneal injection to elicit the renal injury model. The vasodilator peptide adrenomedullin (ADM) is widely distributed in many tissues and has powerful protective effects [82]. In NRK-52E cells, cadmium-inhibited TFEB function causes an increase in ROS to promote pyroptosis, which sheds new light on the therapeutic targets for cadmium-induced kidney diseases [83].…”

Yersiniabactin-Producing E. coli Induces the Pyroptosis of Intestinal Epithelial Cells via the NLRP3 Pathway and Promotes Gut Inflammation

“…The control group received only LB via intraperitoneal injection. Body temperature readings were recorded, and clinical signs were evaluated and scored as previously described [48]. A score of 0 indicated a normal reaction to stimuli, while a score of 1 represented a ruffled coat and a delayed response.…”

“…We conducted specific assays for qRT-PCR and Western blot as previously described [48]. The total RNA was extracted from frozen intestine tissue or harvested cultured cells using the RNAiso Plus Kit from Takara (Dalian, China), and reverse transcription was performed using the PrimeScript RT Master Mix Kit from Takara (Dalian, China) for cDNA synthesis.…”