Iraj Rasooli

Omp34‐Mediated Acinetobacter baumannii Invasion of Human Cervical Carcinoma Epithelial, HeLa Cells, and the Influence of Anti‐Omp34 Antibodies

Acinetobacter baumannii is known for its ability to invade and persist within eukaryotic cells, impacting infection outcomes and disease progression. This study investigates the role of Omp34, a key outer membrane protein (Omp), in A. baumannii interaction with epithelial cells and the protective effects of anti‐Omp34 antibodies (Abs). Omp34 is a key regulator of A. baumannii epithelial cell invasion, influencing bacterial adherence, internalization, and intracellular proliferation. The presence of anti‐Omp34 Abs mitigates A. baumannii ‐induced cellular damage and enhances bacterial clearance. The process involved the expression and purification of Omp34, which in turn induced Abs in BALB/c mice against Omp34. The acute toxicity of Omp34 was studied through a histological analysis conducted on six distinct organs in mice. HeLa cells were infected by A. baumannii ATCC 19606 and a clinical strain. Various aspects of A. baumannii behavior with HeLa cells, including HeLa cell viability, adherence, serum resistance, cell internalization, and intracellular proliferation with and without anti‐Omp34 sera. Cytoskeleton inhibitors were used to study the potential roles played in the process of A. baumannii invasion by microfilaments and microtubules. Omp34 effectively triggered Ab production in mice without resulting in any toxicity. The assay for serum resistance revealed potent bactericidal and antibiofilm effects on both A. baumannii strains. Bacterial internalization was constrained when actin polymerization was inhibited. Examination under the microscope revealed instances of adherence, alterations in the cell membrane, apoptosis, vacuolization, and cell damage. HeLa cells exposed to anti‐Omp34 serum showed decreased cell damage. The results provide substantial evidence of the adherence capacity of A. baumannii to proliferate in the epithelial cells. In conclusion, Omp34 plays a substantial role in regulating interactions between epithelial cells and A. baumannii , the multifaceted nature of which intricately modifies the trajectory of infection within host cells by A. baumannii .

Modulation with anti‐Oma87 antibodies of cytotoxicity, adherence, and internalization of Acinetobacter baumannii in human cervical carcinoma epithelial cells

BamA, an Omp85 superfamily member, is universally conserved and essential for cell viability. Using anti‐Oma87 antibodies, we focus on understanding the effect of Oma87 of Acinetobacter baumannii on pathogenicity. Oma87 was expressed, purified, and used to induce anti‐Oma87 antibodies in BALB/c mice. Acute toxicity of the protein was evaluated in mice. HeLa cells were infected with both live and killed A. baumannii 19606 and a clinical isolate. The effects of anti‐Oma87 sera on A. baumannii adherence, internalization, and proliferation in HeLa cells were studied. The roles of microfilaments and microtubules in A. baumannii invasion were demonstrated by Actin disruption. Reduced bacterial population and biofilm formation were noted. The ability of A. baumannii to provoke autophagy through Oma87 induction leads to incomplete autophagy and potentially facilitates bacterial replication. Actin‐mediated uptake, attachment, and invasion demonstrated A. baumannii survival and multiplication within vacuoles in the host cell. The findings underscore the potential of Oma87 as a therapeutic intervention target in infections caused by A. baumannii. This comprehensive analysis contributes valuable information for understanding the virulence mechanisms of A. baumannii, potentially guiding future strategies to combat infections caused by this pathogen.