Biology subjects

Salazar, A. M.

Publications and source records attributed to Salazar, A. M..

8 recordsLinked to original sources

bioRxiv2026

Ultrasound-mediated blood-brain barrier modulation enhances T-cell access but requires immune activation for effective CNS immunity

Immunotherapy shows limited efficacy in brain tumours, where restricted immune access, antigenic heterogeneity and local immunosuppression constrain durable responses. Low-intensity pulsed ultrasound with microbubbles (LIPU+MB) transiently modulates the blood-brain barrier (BBB) and is widely assumed to enhance immunotherapy by facilitating drug and immune cell penetration into the central nervous system (CNS). However, whether increased anatomical access alone is sufficient to generate effective CNS immunity remains unclear. Here, using a transgenic mouse model with astrocyte-restricted antigen expression, we showed that BBB modulation alone is insufficient to generate functional T-cell immunity in the CNS. Although LIPU+MB enabled rapid T-cell entry, accumulation required prior T-cell activation and integrin-dependent mechanisms, indicating that entry remains governed by canonical immune processes. Moreover, T-cells failed to persist owing to insufficient activation of antigen-presenting cells (APCs) within the CNS. Systemic immune adjuvants (poly-ICLC and IL-2; PI) induced APC activation, promoted tissue-resident-memory-like differentiation and supported durable T-cell responses. LIPU+MB further enhanced these responses by increasing T-cell recruitment, resulting in greater accumulation than with PI alone. Mechanistically, antigen presentation by bone marrow-derived APCs was more critical than that by microglia for the accumulation and persistence of antigen-specifc T-cells in the CNS. In antigenically heterogeneous glioma models resistant to CAR T-cell therapy, combining PI with BBB modulation enhanced the efficacy of immunotherapy, which was mirrored by prolonged survival and endogenous tumour-specific T-cell responses, consistent with epitope spreading. Together, these findings define key limitations of LIPU+MB in enabling effective T-cell therapy and establish that BBB modulation must be coupled to systemic immune activation to support T-cell-mediated antitumour immunity in the CNS.

immunology↗

bioRxiv2026

Reproductive history and cognitive aging: Interactive effects of children and grandchildren in a life history framework

Cognitive decline, particularly Alzheimers disease, represents a significant global health concern. While traditional risk factors are well documented, an evolutionary perspective grounded in life history theory offers critical insights into the intergenerational dynamics influencing cognitive aging. This study empirically analyzed the relationship between reproductive history and late-life cognitive performance in women, as measured by the Montreal Cognitive Assessment Colombian version (MOCA-Col). Specifically, we examined the moderating role of the number of grandchildren on the association between parity and cognitive performance. Using an observational, cross-sectional design with a sample of 145 women (mean age = 69.9 years), a cumulative ordinal logistic regression model was fitted to MOCA-Col scores, incorporating age and the interaction between the standardized number of children and grandchildren. A higher number of children was significantly associated with lower odds of being in a better cognitive category ({beta} = -0.869, SE = 0.305, p = 0.0104, OR = 0.42). Crucially, a significant positive interaction between number of children and number of grandchildren was observed ({beta} = 0.354, SE = 0.093, p < 0.001, OR = 1.42), indicating that the negative association between parity and cognition progressively attenuated as the number of grandchildren increased. This evidence supports human life history models and the grandmother hypothesis, suggesting that intergenerational investment may mitigate the cumulative biological costs of reproduction. The findings reflect an evolutionary trade-off between early reproductive effort and later somatic maintenance.

evolutionary biology↗

bioRxiv2025

A scalable organoid model of urothelial aging for metabolic interrogation, infection modeling, and reversal of age-associated changes

Aging leads to a progressive decline in overall bladder function resulting in lower urinary tract symptoms and increased susceptibility to infections. However, tissue-specific mechanisms of aging, specifically the contributions of the aged urothelium remain elusive. Here, we introduce mouse bladder epithelium-derived organoids (mBEDOs) as a scalable platform to model urothelial aging. mBEDOs from aged mice recapitulate key features of age-associated cellular reprogramming, including oxidative stress, senescence, and DNA damage. We demonstrate the utility of mBEDOs for modeling Uropathogenic Escherichia coli (UPEC) infection, generating assembloids between mBEDOs and macrophages to model epithelial-immune interactions, and genetic perturbation. Using the mBEDO platform, we also identify urothelium-specific changes in purine, amino acid, and glycerophospholipid metabolism which may contribute to age-associated cellular perturbations. Lastly, supplementation with depleted metabolites, nicotinamide (NAM) and D-mannose, reduce DNA damage and oxidative stress and restore mitochondrial integrity in aged mBEDOs. These findings establish mBEDOs as an effective platform for investigating molecular and cellular underpinnings of urothelial aging and exploring metabolism-based interventions for age-associated bladder dysfunction.

bioengineering↗

bioRxiv2025

The role of amygdala calcitonin gene-related peptide receptors on the development of persistent bladder pain in mice.

Bladder pain significantly impacts millions worldwide, severely affecting their quality of life and posing a major clinical challenge. Understanding the mechanisms underlying persistent bladder pain is critical for developing better therapeutic strategies. In this study, we investigate the effects of cyclophosphamide (CYP)-induced persistent bladder sensitization to explore the lateralized contribution of amygdala calcitonin gene-related peptide receptors (CGRP-Rs) on pain-like changes in mice. We demonstrate that CYP induces hypersensitivity lasting up to 14 days post-injury (DPI) in the urinary bladder distention assay and up to 21 DPI when assessing abdominal mechanical sensitivity. Despite persistent pain-like changes, no significant bladder histological changes were observed. Based on previous findings that CGRP signaling from the parabrachial nucleus contributes to central amygdala (CeA) lateralization, we hypothesized that CGRP-Rs play a key role in driving visceral bladder pain-related hemispherical differences. We show that inhibiting CGRP-R activity with the antagonist CGRP8-37, in the right CeA attenuates bladder pain-like behavior, whereas left CeA inhibition sustains CYP-induced hypersensitivity. Electrophysiological recordings revealed increased firing frequency in CGRP-R positive cells in the right CeA 7 DPI. In vivo single photon calcium imaging demonstrated increased Ca transients in CGRP-R-positive cells in the right CeA, upon the presentation of a stimulus at 0 DPI, and overall at 2DPI, further confirming the pronociceptive role of CGRP-Rs in the right CeA. Taken together, these findings provide a crucial foundation for understanding pain-induced CeA lateralization and for further studies identifying how targeting CGRP signaling could provide bladder pain relief.

neuroscience↗

bioRxiv2024

A new role for IFRD1 in regulation of ER stress in bladder epithelial homeostasis

A healthy bladder requires the homeostatic maintenance of and rapid regeneration of urothelium upon stress/injury/infection. Several factors have been identified to play important roles in urothelial development, injury and disease response, however, little is known about urothelial regulation at homeostasis. Here, we identify a new role for IFRD1, a stress-induced gene that has recently been demonstrated to play a critical role in adult tissue proliferation and regeneration, in maintenance of urothelial function/ homeostasis in a mouse model. We show that the mouse bladder expresses IFRD1 at homeostasis and its loss alters the global transcriptome of the bladder with significant accumulation of cellular organelles including multivesicular bodies with undigested cargo, lysosomes and mitochondria. We demonstrate that IFRD1 interacts with several mRNA-translation-regulating factors in human urothelial cells and that the urothelium of Ifrd1-/- mice reveal decreased global translation and enhanced endoplasmic reticulum (ER) stress response. Ifrd1-/- bladders have activation of the unfolded protein response (UPR) pathway, specifically the PERK arm, with a concomitant increase in oxidative stress and spontaneous exfoliation of urothelial cells. Further, we show that such increase in cell shedding is associated with a compensatory proliferation of the basal cells but impaired regeneration of superficial cells. Finally, we show that upon loss of IFRD1, mice display aberrant voiding behavior. Thus, we propose that IFRD1 is at the center of many crucial cellular pathways that work together to maintain urothelial homeostasis, highlighting its importance as a target for diagnosis and/or therapy in bladder conditions.

cell biology↗

bioRxiv2023

Prolonged survival of rabid mice after treatment with Poly-ICLC Hiltonol (R)

Despite its 100% lethality and approximately 59,000 human deaths a year, rabies is still in want of an effective treatment. A host of trials has been described aiming at impairing the life cycle of Lyssavirus rabies (RABV), the chief worldwide lyssavirus causing rabies, but with limited success. In this study, mice intranasally inoculated with the CVS strain of RABV were serially treated with 50{micro}g/day of the Poly ICLC Hiltonol(R) jn MEM showed significantly higher survival time and disease incubation period as compared to control mice that received MEM only. These very preliminary results indicate that Hiltonol(R) might be an effective drug against rabies that merits wider in vivo investigation.

pharmacology and toxicology↗

bioRxiv2023

Natural Killer cell contractility and cytotoxicity is driven by TLR3 agonist-mediated TAZ cytoplasmic sequestration

The evolutionarily conserved YAP/TAZ mechano-responsive transcription cofactors regulate development and tumorigenesis. Here, we show for the first time that human natural killer (NK) cells specifically express TAZ but not YAP, and TAZ serves to limit NK cytotoxicity. The TLR3 agonist, hiltonol, was able to trigger cytoplasmic sequestration of TAZ, which increased NK cytotoxicity. Mechanistically, a low dose of hiltonol enhanced the intracellular contractility of NK cells accompanied by an increase in active RhoA and myosin light chain phosphorylation, conceivably through an increase in ERK1/2 activation-dependent ROS production. Importantly, we showed that the dissociation of LATS1 from actin upon activation of contractility, is required to sequester TAZ in the cytoplasm. Functionally, hiltonol also reduced the NK cell surface inhibitory receptors, KIR3DL1 through c-Myc inhibition and PD-1 through enhanced contractility. Direct inhibition of c-Myc promoted NK cytotoxicity against K562 lymphoblast. We corroborated our findings by coculturing hiltonol-pretreated NK cells with breast and lung cancer cells, and demonstrated increased NK-mediated cancer killing, which conceivably occurred via sequestration of TAZ to the cytoplasm which facilitated NK cytotoxicity. Our findings pave the way for ex vivo rejuvenation of NK cells for in vivo immunotherapies, which could involve a cocktail of hiltonol and c-Myc inhibitor.

cell biology↗

bioRxiv2022

D-mannose ameliorates age-associated cellular senescence in the bladder urothelium and NLRP3/Gasdermin/IL-1β -driven pyroptotic epithelial cell shedding

Aging is a risk factor for disease via increased susceptibility to infection, decreased ability to maintain homeostasis, inefficiency in combatting stress, and decreased regenerative capacity. Multiple diseases including urinary tract infection (UTI), are more prevalent with age; however, the mechanisms underlying how aging affects the urinary tract mucosa and the reason why aging correlates with disease are poorly understood. Here, we show that, relative to young (8-12 weeks) mice, the urothelium of aged (18-24 months) female mice accumulates large lysosomes with decreased acid phosphatase activity and shows overall decreased autophagic flux. Aged bladders exhibit basally high accumulation of reactive oxygen species (ROS) and dampened redox response. Furthermore, the aged urothelium exhibits a canonical senescence-associated secretory phenotype (SASP) at baseline with continuous NLRP3-inflammasome- and Gasdermin D (GSDMD)-dependent pyroptotic cell death. Accordingly, we find that aged mice chronically exfoliate epithelial cells. When infected with uropathogenic E. coli, infected aged mice harbor more bacterial reservoirs post-infection and are prone to spontaneous recurrent UTI. Finally, treatment of aged mice with D-Mannose, a natural bioactive monosaccharide, rescues autophagy flux, reverses SASP, and limits pyroptotic epithelial shedding. Thus, normal aging dramatically affects bladder physiology with aging alone increasing baseline cellular stress and susceptibility to infection. Additionally, our results suggest that mannose supplementation could serve as a senotherapeutic to limit age-associated urothelial dysfunction.

cell biology↗