Neisseria gonorrhoeae is one of the two major pathogens involved in the majority of cases of sexually transmitted genital infection. Complement forms an important aspect of the innate immune system that impacts upon gonococcal infection. Prior work in our laboratory has shown that sialylation of gonococcal lipooligosaccharide (LOS) results in complement resistance by binding the host complement regulatory molecule, factor H. The porin molecule also binds factor H. In the first Specific Aim, we will investigate the role of an alternatively-spliced version of factor H, called factor H-like molecule 1 (FHL-1)in binding to gonococci and in regulating complement. Some strains of N. gonorrhoeae process complement (i.e. convert complement component-3 [C3b] to the inactivated form [iC3b]) and bind FHL-1, but not factor H. Cofactor activity of FHL-1 will be assessed using serum containing only FHL-1, but not intact factor H. Because both factor H and FHL-1 bind to cells, we will examine the roles of these two molecules in facilitating gonococcal attachment to immortalized cervical and urethral epithelial cells, in the second Specific Aim, three questions that pertain to LOS sialylation will be addressed. First, the specificity of factor H binding to gonococcal lacto- N-neotetraose (LNT) sialic acid, but not to meningococcai LNT sialic acid, will be examined. Porin (Por) influences binding of fH to gonococcal sialic acid. We will perform allelic exchange of porin molecules between the two species to examine the effect of porin on the sialylated LOS interactions with factor H that differs at baseline in the two neisserial species. Second, we will examine the determinants of the functional specificity of the LOS sialyltransferase (IsO enzyme in meningococci and gonococci by performing allelic exchanges of the Ist genes between the two species. Third, we will also determine why the efficiency of LOS sialylation differs between serum-sensitive (high sialic acid uptake) and "stably" serum-resistant (low sialic acid uptake) gonococci. This will be performed by examining the uptake of 3H-labeled CMP-NANA by isogenic gonococci differing only in their Lst enzymes. The possibility that Por modifies Lst activity will also be examined by performing allelic exchanges of the Por genes between high and low sialic acid incorporators. In the third Specific Aim, we will detail the linkages (amide versus ester) between C4 and LOS, the effects of hexose extension of the LOS on binding of C4 to LOS, and the impact of the bond formed between C4 and LOS on bactericidal killing.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37AI032725-20
Application #
8440844
Study Section
Special Emphasis Panel (NSS)
Program Officer
Hiltke, Thomas J
Project Start
1993-01-01
Project End
2014-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
20
Fiscal Year
2013
Total Cost
$626,569
Indirect Cost
$245,676
Name
University of Massachusetts Medical School Worcester
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
603847393
City
Worcester
State
MA
Country
United States
Zip Code
01655
Shaughnessy, Jutamas; Gulati, Sunita; Agarwal, Sarika et al. (2016) A Novel Factor H-Fc Chimeric Immunotherapeutic Molecule against Neisseria gonorrhoeae. J Immunol 196:1732-40
Gulati, Sunita; Schoenhofen, Ian C; Whitfield, Dennis M et al. (2015) Utilizing CMP-Sialic Acid Analogs to Unravel Neisseria gonorrhoeae Lipooligosaccharide-Mediated Complement Resistance and Design Novel Therapeutics. PLoS Pathog 11:e1005290
Gulati, Sunita; Mu, Xin; Zheng, Bo et al. (2015) Antibody to reduction modifiable protein increases the bacterial burden and the duration of gonococcal infection in a mouse model. J Infect Dis 212:311-5
Lewis, Lisa A; Gulati, Sunita; Burrowes, Elizabeth et al. (2015) α-2,3-sialyltransferase expression level impacts the kinetics of lipooligosaccharide sialylation, complement resistance, and the ability of Neisseria gonorrhoeae to colonize the murine genital tract. MBio 6:
Del Tordello, Elena; Vacca, Irene; Ram, Sanjay et al. (2014) Neisseria meningitidis NalP cleaves human complement C3, facilitating degradation of C3b and survival in human serum. Proc Natl Acad Sci U S A 111:427-32
Lewis, Lisa A; Ram, Sanjay (2014) Meningococcal disease and the complement system. Virulence 5:98-126
Rice, Peter A (2014) Editorial commentary: The shifting sands of gonococcal antimicrobial resistance. Clin Infect Dis 59:1092-4
Agarwal, Sarika; Vasudhev, Shreekant; DeOliveira, Rosane B et al. (2014) Inhibition of the classical pathway of complement by meningococcal capsular polysaccharides. J Immunol 193:1855-63
Lewis, Lisa A; Vu, David M; Granoff, Dan M et al. (2014) Inhibition of the alternative pathway of nonhuman infant complement by porin B2 contributes to virulence of Neisseria meningitidis in the infant rat model. Infect Immun 82:2574-84
Lewis, Lisa A; Vu, David M; Vasudhev, Shreekant et al. (2013) Factor H-dependent alternative pathway inhibition mediated by porin B contributes to virulence of Neisseria meningitidis. MBio 4:e00339-13

Showing the most recent 10 out of 72 publications