University at Buffalo
The Witebsky Center

The Witebsky Center
University at Buffalo
Bacteriology Host-Microbe Interactions Immunology Parasitology Virology
The Witebsky Center The Witebsky Center
Ashu Sharma, Ph.D.

Associate Professor
Department of Oral Biology
University at Buffalo

Telephone: (716) 829-2759
Fax: (716) 829-3942


Synopsis of Research

   The human oral cavity is a highly diversed ecosystem containing more than 500 species of bacteria, including both cultivable and non-cultivale speciies.  It is believed that infection with a select few Gram-negative anaeobs, called the "red complex", is responsible for causing periodontitis or "gum disease", which if not treated leads to tooth loss.  My lab studies the pathogenic mechanisms of the red-complex bacteria by utilizing molecular-genetic and biochemical approaches; the bacteria of the red-complex include Porphyromonas gingivaix, Tannerella forsythia (formerly Bacteroides forsythus) and Treponema denticola (a spirochete).  The overall objectives of my research are to gain a better understanding of how these pathogenic bacteria initiate colonization, form biofilms and initiate tissue destructive host immune responses critical for disease progression.  The research focuses on identifying the virulence factors these bacteria produce and host-cell receptors involved in recognition of virulence factors.  Once these virulence factors and host cell receptors have been identified, the logical next step would be to develop intervention strategies, such as vaccines, against periodontitis causing bacteria.  In this regard, we have developed genetic systems in non-pathogenic oral streptococci (streptococci gordoni) for expression an delivery of antigens of choice as vectors for oral immunization. 

Current Research Activities:

1.  Characterization of T. forsythia virulence factors:  A cell-surface associated as well as a secreted protein, called the BspA protein, has been identified from T. forsythia in our laboratory.  It belongs to the leucine-rich repeat (LRR) as well as bacterial immunoglobulin domain (Big_2) families of proteins.  Our studies have shown that the BspA possesses multifunctional activities, such as ability to mediate bacterial adherence/invasion into epithelial cells as well as stimulating the release of proinflammatory cytokines from host cells via activating toll-like receptor 2 (TLR2).

2.  Investigation of mixed bacterial biofilms and investigation of T. forsythia genes regulated in biofilms. 

3.  Identification of novel bacterial factors produced by oral microbiome by functional screening of metagenomic libraries.

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