Bacterial endophthalmitis is a vision-threatening complication of penetrating eye injury and intraocular surgery, notably cataract surgery, the most common ophthalmic procedure performed in older populations in the United States. Approximately, 3 out of 1000 patients develop bacterial endophthalmitis after cataract surgery. As the aged population in the US is expected to grow dramatically, the number of cataract surgeries performed will also increase significantly, resulting in a proportional increase in the incidence of endophthalmitis. The visual properties of the retina are highly sensitive to inflammation-caused damage therefore, a rapid detection and clearance of invading pathogens is critical in minimizing retinal damage.
Dr. Kumar’s lab research interests are to understand the regulation of retinal innate immunity in endophthalmitis and to identify the potential targets for intervention. Recognition of microbial infection and initiation of host defense responses is controlled by multiple mechanisms. The host innate immune system uses a series of pattern recognition receptors (PRRs) to detect the presence of pathogens, thus allowing rapid host defense responses to invading microbes. A key component of such receptors is the "Toll-like receptor" (TLR). Previous studies from our laboratory and others have revealed an important role of TLRs in mediating innate immune response at the ocular surface. Although the expression and function of TLRs in many tissues have been studied extensively, few studies are related to the retina. Retinal pigment epithelial (RPE) cells have been shown to express TLR2, TLR3, TLR4, and TLR9. However, many questions fundamental to the understanding of retinal innate immunity remain elusive. For example: what cell types in the retinal tissue are involved in recognition of invading pathogens in endophthalmitis? Does the TLR innate system exist in the retina? If yes, which TLRs are involved? How might retinal cells respond to bacteria or the TLR ligand challenge? The main objective of our research is to define the role of TLRs in bacterial endophthalmitis using mouse models of S. aureus endophthalmitis and cultured retinal cells in vitro. A better understanding of host-pathogen interaction in the retina will allow more effective therapeutic strategies to prevent or treat bacterial endophthalmitis. In addition to research, Dr. Kumar also participates in teaching Medical Histology to first year medical students and Biology of the Eye course to undergraduate students.
Ocular Infectious diseases and their prevention, Innate Immunity, Inflammation, Bacterial pathogenesis
2010: Member, Scientific Review Committee, Fight for Sight foundation.
2010: Editorial board member, World Journal of Gastrointestinal Pathophysiology (WJGP)
2008: Grant Initiative Program Award, Wayne State University, School of Medicine
2008: KEI intramural research grant award.
2007: Fight for Sight grant-in-aid research award.
2006: Midwest eye bank research grant award.
2006: Association for Research in Vision and Ophthalmology (ARVO), travel grant.
2005: Fight for Sight post-doctoral fellowship award
1998: Post Grad Institute of Medical Education & Research fellowship.
1997: Secured first position in order of merit in Masterís Program
Education and Training:
- 1992 – 1995: B S. (Medical), Panjab University (DAV college), Chandigarh, India.
- 1995 –1997: M.S. (Microbiology), Kurukshetra University, Kurukshetra, Haryana, India
- 1998 – 2003: Ph. D. (Medical Microbiology), Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
- 2002 - 2003: Research Associate, Division of Molecular Biology and Yeast Genetics, Institute of Microbial Technology (IMTECH), Chandigarh, India
- 2003 – 2004: Postdoctoral Fellow, Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA
- 2004 – 2005: Postdoctoral Fellow, Kresge Eye Institute (Department of Ophthalmology), Wayne State University, Detroit, MI
Professional and Faculty Appointments:
- 2006 – 2010: Research Scientist, Kresge Eye Institute (Department of Ophthalmology), Wayne State University, Detroit, MI
- 2010 – cont Assistant Professor (tenure-track), Kresge Eye Institute (Department of Ophthalmology), Wayne State University, Detroit, MI
- 2010 – cont Assistant Professor (tenure-track), Department of Anatomy & Cell Biology, Wayne State University, Detroit, MI
NIH grant-R01-EY19888, Fight for Sight and Midwest Eye banks
1. Kumar A, Gao N, Standiford T, Gallo RL and Yu FS. Topical flagellin protects the injured corneas from Pseudomonas aeruginosa infection. Microbes and Infection, 2010 Jul 1 [Epub ahead of print].
2. Yu FS, Cornicelli MD, Kovach MA, Newstead MW, Zeng X, Kumar A, Gao N, Yoon SG, Gallo RL, and Standiford TJ. Flagellin stimulates protective lung mucosal immunity: role of cathelicidin related antimicrobial peptide (CRAMP). Journal of Immunology, 2010, 15; 185(2):1142-9.
3. Gao N, Kumar A, Jyot J and Yu FS. Flagellin-induced corneal antimicrobial peptide production and wound repair involves a novel NF-B-independent and EGFR-dependent pathway. PLOS one, 2010, 26; 5(2):e9351.
4. Kumar A*, Singh CN, Glybina IV, Mahmoud TH, and Yu FS. TLR2 ligand-induced protection against bacterial endophthalmitis. Journal of Infectious Diseases, 2010, 201 (2): 255-263).
5. Zhang J, Kumar A, and Yu FS. Lack of MD2 expression in human corneal epithelia cells is an underlying mechanism of lipopolysaccharides (LPS) unresponsiveness. Immunology and Cell Biology. 2009, 87(2):141-8.
6. Kumar A, Hazlett LD and Yu FS. Flagellin suppresses inflammatory response and enhances bacterial clearance in murine model of Pseudomonas keratitis. Infection and Immunity. 2008, 76(1): 89-96.
7. Kumar A, Yin J, Zhang J and Yu FS. Modulation of corneal epithelial innate immune response to pseudomonas infection by flagellin pretreatment. Investigative Ophthalmology and Visual Science. 2007, 48 (10):4664-4670.
8. Kumar A*, Tassopoulos AM, Li Q, Yu FS. Staphylococcus aureus protein A induced inflammatory response in human corneal epithelial cells. Biochemical Biophysical Research Communication. 2007, 354 (4):955-961.
9. Kumar A* and Yu FS. Toll-like receptors and corneal innate immunity. Current Molecular Medicine 2006, 6 (3):327-337.
10. Kumar A, Zhang J, Yu FS. Toll like receptor-2 mediated expression of beta defensin-2 in human corneal epithelial cells. Microbes and Infection 2006, 8 (2): 380-389.
11. Kumar A, Zhang J, Yu FS. TLR3 agonist Poly (I:C)-induced antiviral response in human corneal epithelial cells. Immunology 2006, 117 (1): 11-21.
12. Kumar A, Zhang J, Yu FS. Innate immune response of corneal epithelial cells to Staphylococcus aureus infection: role of peptidoglycan in stimulating proinflammatory cytokine secretion. Investigative Ophthalmology and Visual Science 2004, 45(10): 3513-3522.
* corresponding author