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Kenneth Whitaker Witwer, Ph.D.

Photo of Dr. Kenneth Whitaker Witwer, Ph.D.
  • Associate Professor of Molecular and Comparative Pathobiology

Research Interests

microRNA; RNA interference; extracellular vesicles; exosomes; retrovirology; genome editing; HIV/AIDS; immunology


Dr. Kenneth W. Witwer is an assistant professor of molecular and comparative pathobiology at the Johns Hopkins University School of Medicine. His research focuses on extracellular vesicles, RNA-mediated regulation, biomarker discovery, and therapeutic modulation of innate and intrinsic defenses.

He received his undergraduate degree from Penn State University, where he studied biochemistry and molecular biology, German, and international politics. He earned a doctorate from the Biochemistry, Cellular and Molecular Biology Program at Johns Hopkins and received a National Science Foundation Graduate Research Fellowship. Dr. Witwer remained at Johns Hopkins to complete a postdoctoral fellowship in microRNA biomarker research, and he joined the faculty in 2011. more


  • Associate Professor of Molecular and Comparative Pathobiology
  • Associate Professor of Neurology

Departments / Divisions

Centers & Institutes



  • Ph.D., Johns Hopkins University School of Medicine (Maryland) (2010)
  • B.A., Pennsylvania State University (Pennsylvania) (1999)

Additional Training

Johns Hopkins University School of Medicine, Baltimore, MD, 2011, Molecular and Comparative Pathobiology

Research & Publications

Research Summary

Dr. Witwer investigates extracellular vesicles and RNA in human disease, including HIV infection and inflammatory disease. Ribonucleic acid (RNA) molecules are found not only inside, but also outside of human cells in biological fluids such as blood plasma, urine, and cerebrospinal fluid. Although quite labile, these molecules are protected from degradation by molecular shuttles including extracellular vesicles (EV). Rapidly expanding research programs over the last several years indicate that EVs and their nucleic acid cargo may provide early warning of disease, contribute to the defense against disease, and serve as models for effective therapies. Dr. Witwer is also interested in extracellular RNA as a potential therapeutic approach.


NIH-funded projects

  • "Extracellular Vesicle-Mediated Immunomodulation in HIV Infection and Nicotine Abuse"
  • "Development of miRNA-based therapies to silence or purge the latent macrophage reservoir in HAND"
  • "Biomarkers of the HIV-associated neurocognitive disorders: plasma and CSF miRNAs in prediction, diagnosis and pathogenesis of HAND" (in collaboration with Dr. Janice Clements)
  • "Circulating cellular and extracellular noncoding RNAs in HIV-1 Elite Suppression" (in collaboration with Dr. Joel Blankson).

Research Opportunities

Rotation projects are available to Cellular and Molecular Medicine students. Local undergraduates with laboratory experience and a strong interest in HIV, RNA, or extracellular vesicle research are encouraged to inquire about available projects. Undergraduates in the Witwer lab have co-authored numerous publications and have earned:

  • Four young investigator awards from professional meetings;
  • One Dean's Undergraduate Research Award (DURA);
  • Five Provost's Undergraduate Research Awards (PURA);
  • Four Center for AIDS Research Baltimore HIV Scholars; and
  • A Second Decade Society scholarship.

Lab Website: Ken Witwer Laboratory

Technology Expertise Keywords

miRNA, genome editing, ultracentrifugation, microarray, RNA-seq, in situ hybridization, molecular biology, immunofluorescence, immunohistochemistry

Selected Publications

View all on Pubmed

EV-TRACK Consortium, Van Deun J, Mestdagh P, et al. EV-TRACK: transparent reporting and centralizing knowledge in extracellular vesicle research. Nature Methods 2017.

Han PA, Kim HS, Cho S, Fazeli R, Najafian A, Khawaja H, McAlexander M, Dy B, Sorensen M, Aronova A, Sebo TJ, Giordano TJ, Fahey TJ 3rd, Thompson GB, Gauger PG, Somervell H, Bishop JA, Eshleman JR, Schneider EB, Witwer KW, Umbricht CB, Zeiger MA. Association of BRAF V600E Mutation and MicroRNA Expression with Central Lymph Node Metastases in Papillary Thyroid Cancer: A Prospective Study from Four Endocrine Surgery Centers. Thyroid 2016.

Kim V, Mears B, Powell BH, Witwer KW. Mutant Cas9-transcriptional activator activates HIV-1 in the presence and absence of LTR-specific guide RNAs. Science Matters 2017.

Eitan E, Hutchison ER, Marosi K, Comotto J, Mustapic M, Nigam S, Suire C, Maharana C, Machairaki V, Witwer KW, Kapogiannis D, Koliatsos VE, Mattson MP. Extracellular Vesicle-Associated Aβ Mediates Trans-Neuronal Bioenergetic and Ca2+-Handling Deficits in Alzheimer's Disease Models. Nature Partner Journal Aging and Mechanisms of Disease 2016.

Buchanan EL, Espinoza DA, McAlexander MA, Myers SL, Moyer A, Witwer KW. SAMHD1 transcript upregulation during SIV infection of the central nervous system does not associate with reduced viral load. Scientific Reports 2016.

Contact for Research Inquiries

Edward D. Miller Research Building
733 N. Broadway
Room 829
Baltimore, MD 21205 map

Email me

Academic Affiliations & Courses

Graduate Program Affiliation

Dr. Witwer is a faculty member of the Cellular and Molecular Medicine graduate program ( 

Activities & Honors


  • Young Investigator Award, 18th Conference on Retroviruses and Opportunistic Infections, 2011
  • Richard T. Johnson Young Investigator Award, International Society for NeuroVirology, 2009
  • Travel Grant, International Society for NeuroVirology, 2009
  • Keystone Symposia Scholarship, Keystone Symposia, 2011
  • Scholl Scholarship, Penn State University, 2001 - 2002
  • Turock Young Scientist Award, Turock Family Foundation, 2002
  • Center for AIDS Research Scholar Award, Johns Hopkins University, 2014
  • Graduate Research Fellowship, National Science Foundation, 2003 - 2006


  • International Society for Extracellular Vesicles, 2012
  • International Society for NeuroVirology, 2009
  • American Society for Exosomes and Microvesicles, 2012
  • American Association for the Advancement of Science, 2002

Professional Activities

  • Secretary General, International Society for Extracellular Vesicles, 0
  • Associate Editor, Journal of Extracellular Vesicles, 0
  • Editorial Board Member, Clinical Chemistry (American Association for Clinical Chemistry), 0
  • Co-Chair, 2018 Gordon Research Conference and Gordon Research Seminar on Extracellular Vesicles, 0
  • Chair, Local Organizing Committee, ISEV2015, International Society for Extracellular Vesicles, 0
  • Panelist, Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) on Human Health and Ecological Risk Assessments for SmartStax PRO, US Environmental Protection Agency, 0
  • Panelist, Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) on RNAi technology as a pesticide, US Environmental Protection Agency, 0
  • Executive Committee Member-at-Large, International Society for Extracellular Vesicles, 0
  • Ad-hoc reviewer, More than 70 scientific journals, 0

Videos & Media

Recent News Articles and Media Coverage

The Retraction War. Jill Neimark, Aeon. December, 2014

Fact or Artifact? Jef Akst, The Scientist. October, 2014

HIV Denial: Alive and Well in 2014. Tara Smith, Aetiology. September, 2014

A Lethal Dose of RNA. Kai Kupferschmidt, Science, August, 2013

So Science...May have Gotten it Wrong. Now What? Virginia Hughes, National Geographic Phenomena. July, 2013

U.S. Government Accuses Open Access Publisher of Trademark Infringement. Jocelyn Kaiser, ScienceInsider. May, 2013

Kenneth Witwer on microRNA and cellular BubblesFundamentals

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