title: RNAi-mediated silencing of fungal acuD gene attenuates the virulence of Penicillium marneffei.
abstract: A number of pathogens, most of them intracellular, employ the glyoxylate cycle in order to ingest fatty acids as carbon sources as a way of coping with nutrient deprivation during the infection process. Isocitrate lyase, which is encoded by the pathogen's acuD gene, plays a pivotal role in the glyoxylate cycle, which has been implicated in fungal pathogenesis. In this study, the acuD gene of Penicillium marneffei was knocked down using siRNA expressed by a filamentous fungi expression system. The acuD siRNA reduced the acuD gene's mRNA and protein expression by 21.5 fold and 3.5 fold, respectively. When macrophages were infected with different transformants of P. marneffei, the knockdown of acuD expression with RNA interference was lethal to the pathogens. In addition, the secretion of tumor necrosis factor-alpha and interferon-gamma from the infected macrophages was reduced. Moreover, the RNAi-mediated silencing of acuD expression reduced the fungal burden in the nude mice infected with P. marneffei; inhibited the inflammatory response in the lungs, livers, and spleens during the chronic phase instead of the acute phase of infection; and thus prolonged survival of the infected animals. Collectively, our data indicate that the RNAi-mediated silencing of acuD expression could attenuate virulence of P. marneffei. The endogenous expression of the delivered siRNA vector could be used to evaluate the role of functional genes by continuous and stable expression of siRNA.
authors.affiliation: Department of Dermatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.
authors.forename: Jiufeng
authors.initials: J
authors.lastname: Sun
authors.forename: Xiqing
authors.initials: X
authors.lastname: Li
authors.forename: Peiying
authors.initials: P
authors.lastname: Feng
authors.forename: Junmin
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Xie
authors.forename: Erwei
authors.initials: E
authors.lastname: Song
authors.forename: Liyan
authors.initials: L
authors.lastname: Xi
mesh_terms: D000825:Animal Structures / Q000382:microbiology; D000818:Animals; D002675:Child, Preschool; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D005260:Female; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007522:Isocitrate Lyase / Q000235:genetics / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D008297:Male; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D050296:Microbial Viability; D009181:Mycoses / Q000382:microbiology / Q000473:pathology; D010407:Penicillium / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016019:Survival Analysis; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; D014409:Tumor Necrosis Factor-alpha; D037521:Virulence Factors; D007371:Interferon-gamma; D007522:Isocitrate Lyase
keywords: Penicillium marneffei; RNA interference; acuD; pathogenesis