- M.B.A. | Pace University, New York, New York: Lubin School of Business, 2014
- Ph.D. | Albert Einstein College of Medicine, Bronx, New York: Microbiology and Immunology, 2006
- M.S. | Long Island University, Brooklyn, New York: Biology, 2001
- B.S. | University of Puerto Rico, Mayagüez, Puerto Rico: Industrial Microbioloy, 1998
- Antimicrobial therapy development
- Central Nervous System (CNS) infections
- Diversity Issues in STEM
- Infectious diseases
Our laboratory primary research goals are directed toward understanding the complex interactions of infectious microorganisms with the immune system, as the balance in this interplay impacts whether host damage occurs.
We are interested in understanding three basic questions:
1. Which mechanisms are used by microbes to invade, survive, and cause disease to the host?
2. How does the host defend itself against infectious organisms?
3. How do microbes adapt to environmental changes?
Unraveling the Mechanisms of Fungal Brain Invasion. The encapsulated fungus Cryptococcus neoformans is the most common cause of fungal meningitis, with the highest rate of disease in patients with AIDS. This microbe has developed its virulence factors by interacting with other organisms in the environment. It enters into the human body via the respiratory tract and the infection is controlled in the lungs of people with normal immunity. When a person’s immune system is defective, C. neoformans moves into the bloodstream and the fungus disseminates with a particular propensity to infect the brain. We are interested in elucidating the mechanisms of CNS invasion by C. neoformans and the interactions of the fungus with cells of the CNS including microglia, astrocytes, and neurons.
Impact of Methamphetamine on Bacterial Skin Infections. The prevalence of methamphetamine (METH) use is estimated at ∼35 million people worldwide, with over 10 million users in the United States. Heavy daily users of METH frequently develop formication, a sensation akin to insects crawling on or under the skin. The result of formication is that users engage in constant skin “picking,” often causing the formation of ulcers that are susceptible to bacterial infections. A marked lack of hygiene among users may also be correlated to higher rates of skin and soft-tissue infections (SSTI). Staphylococcus aureus is the single most important bacterial pathogen in infections among injection drug users, with SSTI being extremely common. Wounds and abscesses associated with METH users are an important care problem at respite centers and healthcare institutions. We are interested in dissecting the cellular and signaling mechanisms by which METH alters the host inflammatory responses and promotes S. aureus infection interfering with wound healing and abscess resolution, leading to chronic wounds that can progress to life-threatening sepsis.
Han, G., A. Havnaer, H. H. Lee, D. Carmichael, and L. R. Martinez. 2020. Biological depletion of neutrophils attenuates pro-inflammatory markers and the development of the psoriatic phenotype in a murine model of psoriasis. Clin Immunol. 210:108294.
Lee, H. H., J. Del Pozzo, S. A. Salamanca, H. Hernandez, and L. R. Martinez. 2019. Reduced phagocytosis and killing of Cryptococcus neoformans biofilm-derived cells by J774.16 macrophages is associated with fungal capsular production and surface modification. Fungal Genet Biol. 132:103258.
Aslanyan, L., H. H. Lee, V. V. Ekhar, R. L. Ramos, and L. R. Martinez. 2018. Methamphetamine impairs IgG1-mediated phagocytosis and killing of Cryptococcus neoformans by J774.16 macrophage- and NR-9640-microglia-like cells. Infect Immun. 87 (2): pii: e00113-18.
Guimaraes, A. J., M. Duarte de Cerqueira, D. Zamith-Miranda, P. H. Lopez, M. L. Rodrigues, B. Pontes, N. B. Viana, C. M. DeLeon-Rodriguez, D. C. Pereira Rossi, A. Casadevall, A. M. Gomes, L. R. Martinez, R. L. Schnaar, J. D. Nosanchuk, and L. Nimrichter. 2018. Host membrane glycosphingolipids and lipid microdomains facilitate Histoplasma capsulatum internalization by macrophages. Cell Microbiol. 14:e12976.
Martinez, L. R., D. W. Boucaud, A. Casadevall, and A. August. 2018. Factors Contributing to the Success of NIH-Designated Underrepresented Minorities in Academic and Nonacademic Research Positions. CBE-Life Sci Educ. 17:ar32.
Cordero, R. J., S. C. Liedke, G. De Souza-Araujo, L. R. Martinez, L. Nimrichter, S. Frases, J. M. Peralta, A. Casadevall, M. L. Rodrigues, J. D. Nosanchuk, and A. J. Guimaraes. 2016. Enhanced virulence of Histoplasma capsulatum through transfer and surface incorporation of glycans from Cryptococcus neoformans during co-infection. Sci Rep. 6:21765.
Ahmadi, M., H. H. Lee, D. A. Sanchez, A. J. Friedman, M. T. Tar, K. P. Davies, J. D. Nosanchuk, and L. R. Martinez. 2016. Sustained nitric oxide releasing nanoparticles induce cell death in Candida albicans yeast and hyphal cells preventing biofilm formation in vitro and in a rodent central venous catheter model. Antimicrob Agents Chemother. 60:2185-2194.
Krishnamoorthy, S., Shah, B. P., Lee, H. H., and L. R. Martinez. 2015. Microbicides alter the expression and function of RND-type efflux pump AdeABC in biofilm-associated cells of Acinetobacter baumannii clinical isolates. Antimicrob Agents Chemother. 60:57-63.
Radu, M. R., J. Roman-Sosa, A. K. Varshney, E. A. Eugenin, B. P. Shah, H. H. Lee, L. N. Nguyen, A. J. Guimaraes, B. C. Fries, J. D. Nosanchuk, and L. R. Martinez. 2015. Methamphetamine alters the antimicrobial efficacy of phagocytic cells during methicillin-resistant Staphylococcus aureus skin infections. mBio. 6:e01622-15.
Patel, D., G. M. Desai, S. Frases, R. J. Cordero, C. M. DeLeon-Rodriguez, E. A. Eugenin, J. D. Nosanchuk, and L. R. Martinez. 2013. Methamphetamine enhances Cryptococcus neoformanspulmonary infection and dissemination to the brain. MBio. 4:e00400-13.