Louisiana Via Research Day Book 2026

Biomedical Research: Section 1

Biomedical Research: Section 1

Christian Capers, OMS-III 1 ; David Kang, OMS-III 1 ; Jedidiah, Lim, OMS-III 1 ; Vishveshvar Ramkumar, OMS-III 1 ; Kasia Michalak, MSc 1 ; Maysoon Makhlouf, PhD 1 ; Zakaria Abd Elmageed, PhD 1 ; Hassan Ebrahim, PhD 1 ; Khalid El Sayed, PhD 2 1 VCOM-Louisiana; 2 School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe 5 THE DIBENZOFURAN LICHEN ACID: A NOVEL SCAFFOLD FOR THE CONTROL OF TRIPLE-NEGATIVE BREAST MALIGNANCIES

Carlie Christ, OMS-III 1 *; Sherine Thomas, OMS-III 1 *; Meredith Gwin, PhD 2 ; Samir Gautam, MD; Edward P. Manning, MD 2 ; Melissa Lipsmeyer, PhD 1 , Rebekah Morrow, PhD 3 ; K. Adam Morrow, PhD 1 ; Brant Wagener, MD 4 ; Jean-Francois Pittet, MD 4 ; Tiru Rangasamy, PhD 5 ; Sarah Voth, PhD 1 *Indicates equal contributions 1 Cell Biology and Physiology, VCOM-Louisiana; 2 Pulmonary, Critical Care, and Sleep Medicine, Yale School of Medicine; 3 Microbiology and Immunology, VCOM-Louisiana; 4 Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham; 5 Pathobiological Science, Louisiana State University School of Veterinary Medicine 6 THE DOSE MAKES THE POISON: OPTIMIZING A MURINE MODEL OF PNEUMONIA INDUCED ACUTE RESPIRATORY DISTRESS DISORDER

Context: Breast cancer (BC) remains the most commonly diagnosed cancer in American women, with over 40,000 deaths projected in 2025. BC encompasses various disease subtypes with distinct biological, clinical and prognostic characteristics. Among these, triple-negative breast cancer (TNBC) is characterized by the lack of positive staining for the estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor 2 (HER2). This lack of targetable receptors renders TNBC inherently resistant to the current BC- targeted therapies, resulting in poorer recurrence-free and overall survival rates compared to other BC subtypes. The receptor tyrosine kinase c-Met, a membrane bound receptor activated by hepatocyte growth factor (HGF), plays a crucial role in promoting cell proliferation, survival, motility, and angiogenesis. c-Met is frequently overexpressed or dysregulated in TNBC, making it a compelling therapeutic target. Lichens, a symbiotic association between a fungus (mycobiont) and a photosynthetic partner (photobiont, typically alga or cyanobacterium), serve as a unique resource of the discovery of bioactive compounds.

Objectives and/or Hypothesis: Our previous studies identified the dibenzofuran usnic acid (UA) from Louisiana-grown lichens and developed more than 50 chemically optimized analogs with notable anticancer activity, selectively targeting TNBC cells. This study aims to further investigate the molecular targets of these analogs that are most likely mediating their anticancer mechanism. Methods: Analog U26 was synthesized using Claisen-Schmidt carbon coupling, and its identity was confirmed by NMR and mass spectrometry. Phenotypic screening assays, including cell proliferation, migration and colonization, were implemented to evaluate the anticancer effect of U26 on TNBC cells. Additionally, immunoblotting was utilized to investigate the proteomic profile of TNBC cells treated with U26. Results: U26 was successfully synthesized and demonstrated significant suppression of TNBC cell proliferation, migration and colonization at sub-micromolar levels. Western blot analyses revealed a dose-dependent downregulation of c-Met receptor tyrosine kinase in U26-terated TNBC cells.

Conclusions: Natural products and their analogs continue to serve as valuable resources for discovering novel anticancer biomolecules. The lichen-derived dibenzofuran usnic acid analogs, such as U26, are potential c-Met modulators for TNBC treatment. Further preclinical studies are necessary to validate U26 as a lead compound for therapeutic development.

Results: All mice instilled with either PBS vehicle or 105 or 106 colony forming units (CFU) of ExoY+ or PA808 survived the full 48-hour time course. All mice instilled with 107 CFU of either bacterium died prior to 48-hours. Mice instilled with PA808 lost weight in a dose dependent manner. Those instilled with 107 ExoY+ all gained significant weight with minimal urine output prior to early death. Necropsy revealed massive pulmonary and multi-organ edema in these animals. Histology revealed indices of acute lung injury including infiltration, flooding, and thickened septa, with microthrombi formation in a dose dependent manner with both ExoY+ and PA808 infected animals. Plasma CysC and amyloid burden increased in direct proportion to dose. Conclusions: Infected animals developed pathology ranging from acute lung injury to ARDS in a dose dependent manner. The 106 CFU dose was the most effective for inducing ARDS with both the lab strain ExoY+, and the clinical isolate, PA808, in both male and female mice. This work effectively established a translational model of ARDS for use in future mechanistic studies.

Methods: All animal experiments were approved by the Louisiana School of Veterinary Medicine IACUC. Clinical strain PA808 was isolated from the bronchoalveolar lavage fluid of a patient diagnosed with a monomicrobial nosocomial pneumonia by clinical collaborators at University of Alabama Birmingham. Male and female 10-week-old wildtype C57BL/6J mice were anesthetized with isofluorane (1-3%). Animals were instilled with 40 ul of either sterile PBS vehicle or different concentrations (105, 106, 107 bacteria) of ExoY+ or PA808 via intratracheal cut down. Methacrylate was used to repair the wound and a single injection of buprenorphine XR was used for pain management. Body temperature was maintained during recovery and their diet was fortified with NutraGel to encourage recovery. Weight and urine were collected prior to infection and every 24 h afterward. At 48-hours post-infection, surviving mice were sacrificed. Urine was collected via cystocentesis, blood was collected via cardiac puncture, and the lungs, kidneys, and liver were collected for histology and RT-qPCR. Plasma and urine levels of protein, CysC, albumin, and creatinine were measured with ELISA. Amyloid and tau levels were determined with immunoblotting and thioflavin T.

Rationale: Acute respiratory distress syndrome (ARDS) is characterized by pulmonary edema, refractory hypoxemia, and a mortality rate of ~ 45%. Coagulopathy and acute kidney injury frequently complicate ARDS pathology. Pseudomonas aeruginosa infection is a leading cause of ARDS particularly strains armed with a type III secretion system (T3SS) to inject toxins directly into host cells. Roughly 90% of clinical strains utilize exoenzyme Y (ExoY) in their T3SS arsenal. ExoY is an edema factor that aggressively disrupts endothelial barrier integrity and converts cytoprotective endothelial amyloids into cytotoxic prions. In the absence of ExoY intoxication endothelial amyloids including amyloid-beta (Aß) increase both the innate resistance and resilience of the pulmonary endothelial barrier during infection. Infection elicited tau disrupts the innate function of endothelial amyloids and promotes the dissemination of tau and Aß cytotoxins to promote secondary end-organ damage. However, the mechanisms responsible remain poorly resolved and studies to date have only utilized isogenic lab strains of P. aeruginosa. Here, we utilized a novel clinical isolate of ExoY-competent P. aeruginosa to establish a translationally relevant mouse model of pneumonia induced ARDS for use in future mechanistic studies.

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2026 Research Recognition Day