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  1. Science & Research (NCTR)

Kuppan Gokulan Ph.D.

Staff Fellow — Division of Microbiology

Kuppan Gokulan
Kuppan Gokulan, Ph.D.
(870) 543-7121
NCTRResearch@fda.hhs.gov  

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 About  |  Publications 

Background

Dr. Kuppan Gokulan began his research career in interdisciplinary science including Microbiology and Immunology at the All-India Institute of Medical Sciences, New Delhi, India.  His graduate research was primarily focused on peptide-based vaccine design against human immunodeficiency virus (HIV). Dr. Gokulan was a postdoctoral fellow at Texas A&M University, College Station, Texas (TAMU) in Veterinary Pathology. Thereafter, he was appointed as a senior research scientist in the Department of Biochemistry and Biophysics at TAMU, where he mentored students on research projects that resulted in several publications.
 
Dr. Gokulan’s talents and research expertise in protein chemistry, structural biology, molecular microbiology, and immunology attracted him to NCTR. He was selected for the competitive FDA Commissioner’s Fellow Program in 2010. His scientific endeavors made significant contributions to the research/regulatory priority areas of NCTR and FDA. Dr. Gokulan is currently leading two approved research projects: (1) Safety and risk assessment of nanocrystal formulated poorly soluble BCS-II drug using an in-vivo and ex-vivo model and (2) Computational and high-throughput approach to determine the structure of cell wall synthesis enzyme with inhibitor against for antimicrobial-resistant (AMR) bacteria. He recently identified FDA-approved drug targeting a second pathway in bacterial cell-wall synthesis. 

He established collaborative research with FDA’s Center for Drug Evaluation and Research and the University of Connecticut to address problems associated with the toxicity of a nanocrystal-formulated drug. As a co-investigator, Dr. Gokulan performed risk assessments of several xenobiotic compounds using non-animal and animal models under an interagency agreement with the National Toxicology Program. To address the regulatory needs of FDA’s Center for Veterinary Medicine (CVM) for the risk assessment of antimicrobial drug residues in food animals, Dr. Gokulan is currently assessing the effects of residual levels of antibiotics on the barrier functions of human-intestinal epithelial cells. Dr. Gokulan has been an adjunct faculty member in the Department of Physiology and Biophysics at the University of Arkansas for Medical Sciences since 2011.
 

Honors and Awards

  • 2024 — NCTR Group Recognition Award for excellence in pharmaceutical formulations, research, and collective contributions to furthering FDA’s mission by nanocrystal formulations to benefit public health.  
  • 2023 — NCTR Outstanding Service Award for initiative and perseverance to bring new approaches and techniques to support multidisciplinary and technology driven research projects. 
  • 2023 — NCTR/FDA Special Act Award for exemplary research in highlighting the importance of microbiomes in toxicity.
  • 2017 — NCTR Group Award for outstanding research and regulatory impacts by providing data to CVM on the effect of short- and long-term exposure of residual levels of tetracycline in food on the intestinal microbiome.
  • 2017 — NCTR/FDA Special Act Award for contributions to “Tetracycline Residue and Microbiome Interaction.”
  • 2014 — NCTR Outstanding Service Award for his contribution in microbiome and host-cell interaction.
     

Research Interests

Dr. Gokulan’s lab is involved in generating experimental data to support regulatory reviewers in the areas of:

  1. Safety assessment of nanocrystal-drug using an in vivo animal model to determine effects on gastrointestinal-tract microbiome and function. Approximately 82% of drug nanocrystal investigative new drug applications are for oral administration. To aid FDA’s regulatory mission, experimental data to assess the effect of nanocrystal drugs on the human gastrointestinal tract is important.
  2. Computational modelling and high-throughput screening approach to determine the structure of cell wall synthesis enzyme with inhibitor complexes against AMR and multidrug-resistant (MDR) bacteria. Recently Dr. Gokulan developed a cell culture-based, high-throughput screening assay for drug discovery against antibiotic-resistant bacteria. Through these efforts, they found a bacterial cell-wall enzyme which is responsible for antibiotic resistance. Over-expression of this enzyme in E. coli mimicked MDR bacteria. His lab recently identified a previously approved drug targeting a secondary pathway in bacterial cell-wall synthesis, that is highly expressed in drug and MDR bacteria.
  3. Develop a coronavirus epitope-peptide vaccine candidate to prevent and treat SARS-CoV2. Dr. Gokulan has modeled a complete structure of the receptor binding domain of the spike protein of SARS-CoV2, receptor-binding domain movement upon open and closed conformation, predicted three regions responsible for interacting with ACE2 receptor, and predicted B-cell antigenic epitopes based on the three-dimensional structure.  
  4. Interaction of xenobiotics with gastrointestinal system using animal and nonanimal models. Dr. Gokulan’s lab is also addressing the antibacterial effects of aloin, which has been used in dietary supplements, laxatives, weight loss supplements, beverages, beauty/cosmetics products, and vitamins, against intestinal commensal-bacterial species.  
     


Professional Societies/National and International Groups                                                         

American Society of Microbiology 
Member
2012 – Present

Association of Clinical Biochemistry of India
Member
1994 – Present

FDA Immunology Working group
Member
2020 – 2021

FDA-National Institutes of Health-National Institute of Standards and Technology-U.S. Department of Agriculture Joint Agency Microbiome
Member
2018 – 2021

Indian Immunological Society
Member
1991 – Present

Nanocore Task Force
Member
2020 – Present

Tuberculosis Structural Genomic Consortium 
Member
2001 – Present
 

Selected Publications

Strategies to Enhance Nanocrystal Formulations for Overcoming Physiological Barriers Across Diverse Routes of Administration.  
Yanamadala Y., Muthumula C.M.R., Khare S., and Gokulan K. 
Int J Nanomedicine. 2025, 20:367-402. doi: 10.2147/IJN.S494224.

Early Developmental Exposure to Triclosan Impacts Fecal Microbial Populations, IgA and Functional Activities of the Rat Microbiome. 
Lahiani M., Gokulan K., Sutherland V., Cunny H.C., Cerniglia C.E., and Khare S. 
J Xenobiot. 2024;14(1):193-213. doi: 10.3390/jox14010012. 

Evaluation of Mucosal Immune Profile Associated with Zileuton Nanocrystal-Formulated BCS-II Drug Upon Oral Administration in Sprague Dawley Rats. 
Khare S., Jog R., Bright A., Burgess D.J., Chakder S.K., and Gokulan K. 
Nanotoxicology. 2023;(10):583-603. doi: 10.1080/17435390.2023.2289940. 

Route of Arsenic Exposure Differentially Impacts the Expression of Genes Involved in Gut-Mucosa-Associated Immune Responses and Gastrointestinal Permeability. 
Gokulan K., Mathur A., Kumar A., Vanlandingham M.M., and Khare S. 
International Journal of Molecular Sciences. 2023, 24(7):6352. doi: 10.3390/ijms24076352. 

Preclinical In Vitro Model to Assess the Changes in Permeability and Cytotoxicity of Polarized Intestinal Epithelial Cells during Exposure Mimicking Oral or Intravenous Routes: An Example of Arsenite Exposure. 
Parajuli P., Gokulan K., and Khare S. 
International Journal of Molecular Sciences. 2022, 23(9):4851. doi: 10.3390/ijms23094851. 

Lung Microbiome, Gut-Lung Axis and Chronic Obstructive Pulmonary Disease. 
Gokulan K., Joshi M., Khare S., and Bartter T. 
Current Opinion in Pulmonary Medicine. 2022, 28(2):134-138. http://dx.doi.org/10.1097/mcp.0000000000000853

Ex Vivo Human Colon Tissue Exposure to Pristine Graphene Activates Genes Involved in the Binding, Adhesion and Proliferation of Epithelial Cells. 
Lahiani M.H., Gokulan K., Williams K.W., and Khare S.
International Journal of Molecular Sciences. 2021, 22(21), 11443;

Impact of Chronic Tetracycline Exposure on Human Intestinal Microbiota in a Continuous Flow Bioreactor Model.
Ahn Y., Jung J.Y., Kweon O., Veach B.T., Khare S., Gokulan K., Piñeiro S.A., and Cerniglia C.E.
Antibiotics. 2021, 10(8):886. doi: 10.3390/antibiotics10080886.

Co-Exposure to Boscalid and TiO2 (E171) or SiO2 (E551) Downregulates Cell Junction Gene Expression in Small Intestinal Epithelium Cellular Model and Increases Pesticide Translocation.
Cao X., Khare S., DeLoid G.M., Gokulan K., and Demokritou P.
NanoImpact. 2021, 22:100306. doi: 10.1016/j.impact.2021.100306 [Epub 2021 Mar 10].

Conformational Changes of the Receptor Binding Domain of SARS-CoV-2 Spike Protein and Prediction of a B-cell Antigenic Epitope Using Structural Data.
Khare S., Azevedo M., Parajuli P., and Gokulan K.
Front. Artif. Intell. 2021, 4:630955. doi: 10.3389/frai.2021.630955 [eCollection 2021].

Differential Toxicological Outcome of Corn Oil Exposure in Rats and Mice as Assessed by Microbial Composition, Epithelial Permeability and Ileal Mucosa Associated Immune Status.
Gokulan K., Kumar A., Lahiani H., Sutherland V., Cerniglia C.E., and Khare S.
Toxicological Sciences. 2021, 180(1):89-102. doi: 10.1093/toxsci/kfaa177.

Human Intestinal Tissue Explant Exposure to Silver Nanoparticles Reveals Sex Dependent Alterations in Inflammatory Responses and Epithelial Cell Permeability.
Gokulan K., Williams K., Orr S.E., and Khare S.
Int. J. Mol. Sci. 2020, 22(1):9. doi: 10.3390/ijms22010009.

Sex-Dependent Effects on Liver Inflammation and Gut Microbial Dysbiosis After Continuous Developmental Exposure to Trichloroethylene in Autoimmune Prone Mice.
Blossom S.J., Gokulan K., Arnold M.G., and Khare S.
Frontiers in Pharmacology. 2020, 11:569008. doi: 10.3389/fphar.2020.569008 [eCollection 2020].

Effects of Acute and Chronic Exposure to Residual Level Erythromycin on Human Intestinal Epithelium Cell Permeability and Cytotoxicity.
Hao H., Gokulan K., Piñeiro S.A., Williams K.M., Yuan Z., Cerniglia C.E., and Khare S.
Microorganisms. 2019, 7(9). pii: E325. doi: 10.3390/microorganisms7090325.

The Impact of Pristine Graphene on Intestinal Microbiota Assessed Using a Bioreactor-Rotary Cell Culture System.
Lahiani M., Gokulan K., Williams K., and Khare S.
ACS Appl Mater Interfaces. 2019, 11(29):25708-25719. doi: 10.1021/acsami.9b07635 [Epub 2019 Jul 12].

A Single or Short Time Repeated Arsenic Oral Exposure in Mice Impacts mRNA Expression for Signaling and Immunity Related Genes in the Gut.
Arnold M.G., Gokulan K., Doerge D.R., Vanlandingham M., Cerniglia C.E., and Khare S.
Food Chem Toxicol. 2019, 132:110597. doi: 10.1016/j.fct.2019.110597 [Epub 2019 Jun 21].

Alteration in the mRNA Expression of Genes Associated with Gastrointestinal Permeability and Ileal TNF-α Secretion Due to the Exposure of Silver Nanoparticles in Sprague-Dawley Rats.
Orr S.E., Gokulan K., Boudreau M., Cerniglia C.E., and Khare S.
J Nanobiotechnology. 2019, 17(1):63. doi: 10.1186/s12951-019-0499-6.

Aloin Alters the Intestinal Bacterial Community Structure and Short Chain Fatty Acids Metabolism. 
Gokulan K., Kolluru P., Cerniglia C.E., and Khare S.
Front. Microbiol. 2019, doi: 10.3389/fmicb.2019.00474.

Drug Resistance in Mycobacterium tuberculosis and Targeting the L,D-Transpeptidase Enzyme.
Gokulan K. and Varughese K.I.
Drug Dev Res. 2018, doi: 10.1002/ddr.21455.

Irreversible Effects of Trichloroethylene on the Gut Microbial Community and Gut-Associated Immune Responses in Autoimmune-Prone Mice.
Khare S., Gokulan K., Williams K., Bai S., Gilbert K.M., and Blossom S.J.
J Appl Toxicol. 2019, doi: 10.1002/jat.3708.

Structure and Inhibitor Specificity of L,D-Transpeptidase (LdtMt2) from Mycobacterium Tuberculosis and Antibiotic Resistance: Calcium Binding Promotes Dimer Formation.
Gokulan K., Khare S., Cerniglia C.E., Foley S.L., and Varughese K.I.
AAPS J. 2018, 20(2):44. doi: 10.1208/s12248-018-0193-x.

Exposure to Arsenite in CD-1 Mice During Gestational to Adult Developmental Stages: Effects on Intestinal Microbiota and Gut-Associated Immune Response.
Gokulan K., Arnold M., Jensen J., Vanlandingham M., Twaddle N.C., Doerge D.R., Cerniglia C.E., and Khare S.
MBio. 2018, 9(4). pii: e01418-18. doi: 10.1128/mBio.01418-18.

An In Vitro Study to Assess the Impact of Tetracycline on the Human Intestinal Microbiome.
Jung J.Y., Ahn Y.B., Khare S., Gokulan K., Piñeiro S.A., and Cerniglia C.E.
Anaerobe. 2018, 49:85-94.

Effects of Residual Levels of Tetracycline on the Barrier Functions of Human Intestinal Epithelial Cells.
Gokulan K., Cerniglia C.E., Thomas C., Pineiro S.A., and Khare S.
Food and Chemical Toxicology. 2017, 109(1):253-263.

Graphene and Carbon Nanotubes Activate Different Cell Surface Receptors on Macrophages Before and After Deactivation of Endotoxins.
Lahiani M.H.†, Gokulan K.†, Williams K., Khodakovskaya M.V., and Khare S.
Journal of Applied Toxicology. 2017, 37(11):1305-1316.
† Contributed equally

Contact Information
Kuppan Gokulan
(870) 543-7121
Expertise
Expertise
Approach
Domain
Technology & Discipline
Toxicology
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