Preclinical Disease Models Research Articles

P25 Identification of early changes in extracellular microRNA biomarkers of scleroderma for point-of-care diagnosis

Abstract Introduction and aims Scleroderma is a rare autoimmune disease, characterized by excessive extracellular matrix deposition leading to chronic inflammation and fibrosis. As a progressive disease initially affecting the skin, it presents similarly to Raynaud phenomenon, which delays diagnosis and treatment. Clinical diagnostic tests lack sensitivity, therefore novel Methods of detection and sensitive biomarkers are required to improve diagnosis rates. MicroRNAs are short, stable, noncoding RNAs, often present in the extracellular space, and can be sampled from interstitial skin fluid (ISF) through the employment of hydrogel microneedles. We aim to use this technique to improve upon current clinical gold standards of diagnosing scleroderma, at earlier stages of the disease. Methods In this study, we performed next-generation small-RNA sequencing on ISF from healthy individuals, patients prior to a clinical diagnosis of scleroderma [termed very early detection of systemic sclerosis (VEDOSS)], and patients with scleroderma classified as low and high skin score, identifying a panel of microRNA biomarkers for scleroderma diagnosis. Swellable hydrogel microneedles were manufactured in house, applied to excised human tissue and preclinical mouse models to demonstrate the ability to access and quantify extracellular microRNAs in ISF. Results Patients who received a VEDOSS diagnosis have increased ISF abundance of miR-379-5p and miR-125a-5p and decreased miR-30e-3p compared with healthy patients. miR-379-5p, miR-363-3p and miR-221-3p are sensitive to the progression of scleroderma and could be used to track the disease with improved sensitivity to autoantibodies in blood or where clinical practices usually require a skin biopsy. Using preclinical models of skin disease, we could differentiate between conditions, with higher sensitivity than blood sampling using our microneedle technology. Conclusions By identifying extracellular mircoRNAs, we have shown the potential use of these sensitive biomarkers in a liquid biopsy that can be applied at point-of-care. Peptide nucleic acids complementary to our microRNA biomarkers, will be used to provide real-time on-the-chip readouts of these ­biomarkers.

The potential for senotherapy as a novel approach to extend life quality in veterinary medicine.

Cellular senescence, a condition where cells undergo arrest and can assume an inflammatory phenotype, has been associated with initiation and perpetuation of inflammation driving multiple disease processes in rodent models and humans. Senescent cells secrete inflammatory cytokines, proteins, and matrix metalloproteinases, termed the senescence associated secretory phenotype (SASP), which accelerates the aging processes. In preclinical models, drug interventions termed "senotherapeutics" selectively clear senescent cells and represent a promising strategy to prevent or treat multiple age-related conditions in humans and veterinary species. In this review, we summarize the current available literature describing in vitro evidence for senotheraputic activity, preclinical models of disease, ongoing human clinical trials, and potential clinical applications in veterinary medicine. These promising data to date provide further justification for future studies identifying the most active senotherapeutic combinations, dosages, and routes of administration for use in veterinary medicine.

Leveraging dirty mice that have microbial exposure to improve preclinical models of human immune status and disease.

Leveraging dirty mice that have microbial exposure to improve preclinical models of human immune status and disease.

Nitro-fatty acid signaling: Therapeutic potential in inflammatory diseases

This review explores the interaction between nitric oxide-derived reactive species and unsaturated fatty acids, leading to the formation of electrophilic nitroalkenes, named nitro-fatty acids (NO2-FA). These species serve as endogenously produced anti-inflammatory signaling mediators, demonstrating protective effects in pre-clinical animal disease models. The discussion herein focuses on the cell signaling actions of NO2-FA, drawing insights from both existing knowledge and recent in vivo data. Additionally, this review addresses the potential pharmacological utility of NO2-FA and ongoing trials, highlighting their promising prospects based on the gathered information.

PAG Masked Protective Physical Exercise-Induced High H2S Levels in 5/6 Nephrectomized Rats

Background: To investigate the mechanisms of exercise therapeutics in preclinical animal models of chronic kidney disease (CKD), PAG (D, L-propargylglycine), an inhibitor of hydrogen sulfide production, was used to examine the protective effects of physical activity on oxidative stress and inflammation levels during CKD. Methods: Male Wistar rats with CKD, induced by the 5/6 nephrectomy procedure and subjected to 8 weeks of exercise training, received injections of PAG, a cystathionine γ-lyase (CSE) inhibitor, at a dose of 19 mg/kg, i.p., twice a week during those 8 weeks. The systolic blood pressure (BP) and renal sympathetic nerve activity (RSNA) were assessed. Additionally, plasma creatinine, BUN, renal hydrogen sulfide (H2S) levels, oxidative stress, and inflammatory markers were evaluated. Results: In the PAG group, inhibition of H2S production significantly reversed the improvements in plasma creatinine, BUN, renal malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, TNF-α, and IL-6 that were achieved by exercise. Additionally, high RSNA and high BP, which were also reversed in the PAG group, compared to the CKD group subjected to exercise training. Conclusions: The results suggest that the improvement in BP, oxidative stress, and inflammation status by exercise in CKD may be at least partially due to CSE/H2S signaling.

Pancreatic and hepatic histopathology of high-fat diet fed streptozotocin-induced Wistar rat model of type 2 diabetes mellitus

In search of new fangled therapeutic agents against type 2 diabetes mellitus (T2DM), an appropriate preclinical disease model is important to ensure the success of subsequent clinical trials. There is an increasing trend in the use of high-fat diet (HFD) fed streptozotocin (STZ)-induced rodent models in investigating novel therapeutic agents against T2DM. Though several studies have been conducted on the development of the aforementioned model they were mainly focused on biochemical characteristics. Only limited studies have focused on histopathological changes which is the gold standard in investigating the treatment-related changes of novel therapeutic agents. Therefore, the present study aimed at assessing the histopathological changes of the pancreas and liver, the two main organs involved in glucose homeostasis, in a newly developed HFD-fed STZ-induced Wistar rat model. For this study, Wistar rats were induced with T2DM by intraperitoneal injection of STZ (30, 40, and 50 mg/kg) which was given after feeding the rats with an HFD consisting of 60% calories from fat for four weeks duration. Diabetic rats were sacrificed after maintaining for further four weeks. The liver and pancreas were excised and hematoxylin and eosin-stained sections were observed using a light microscope. The major histopathological changes in the pancreas of HFD-fed STZ-induced diabetic rats were loss of pancreatic islets, pancreatic islet hypertrophy, and mild fatty change in the exocrine pancreas. In contrast, the liver did not show any degree of fatty change, but the majority showed prominent hydropic degeneration in the hepatocytes. In conclusion, prominent alterations were well noted in the pancreatic and liver tissues of the Wistar rats fed with HFD, followed by STZ (50 mg/kg), and the established model could be useful in investigating and elucidating antidiabetic mechanisms of novel pharmaceutical agents.

Elucidating inflammation-induced cell fate decisions in primary human Tregs

Abstract Adoptive regulatory T-cell (Treg) therapy has remarkable efficacy in promoting immune tolerance in preclinical models of transplantation and autoimmune disease. However, lineage-tracing studies have revealed that Tregs can undergo epigenetic reprogramming in chronically inflamed tissue environments, resulting in the acquisition of proinflammatory functions and the capacity to exacerbate autoimmunity. Despite intense interests in developing Treg therapy for humans, inflammation-induced human Treg lineage-decommitment remains poorly understood. Here, we present a robust in vitro model of IL6, IL1β, and IL23-driven human Treg instability characterized by progressive FOXP3 and HELIOS downregulation, FOXP3 conserved non-coding sequence (CNS)-2 enhancer re-methylation, diminished in vitro suppressive function, and elevated proinflammatory cytokine expression. Single-cell transcriptomic and chromatin accessibility analyses of human Tregs undergoing destabilization revealed a gradual closing of a Treg-specific element (A) and a reciprocal opening of a competing element (B) at the IRF4 locus. CRISPR-mediated excision of the B element (IRF4ΔB) preserved Treg identity and enhanced in vitro suppressive activity following prolonged inflammatory exposure. Ongoing experiments aim to evaluate the in vivo function and stability of IRF4ΔB Tregs in a xenogeneic graft-versus-host model. These findings may facilitate the design of Treg therapeutics with greater potency and improved safety.

Abstract 2036: Prognostic Impact Of Pfkfb3 Expression In Endothelial Cells Insights From Peripheral Arterial Disease Patients And The Effects Of Supervised Exercise

Background: Glycolysis constitutes 85% of ATP production in endothelial cells (ECs). Although upregulating PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3), the rate-controlling enzyme for EC glycolysis, has been considered a mean to induce angiogenesis, our group found this approach ineffective or even harmful in pre-clinical peripheral arterial disease (PAD) models. However, no EC specific PFKFB3 data in human PAD patients exists. Hypothesis: EC PFKFB3 upregulation is associated with poor prognosis in PAD patients. Goal: Assess PFKFB3 in ECs and correlate its’ expression with PAD clinical presentation and outcome. Methods: CD31 (EC marker) and PFKFB3 immunostaining was performed on age-matched gastrocnemius (GA) muscle sections from healthy adult control (HA), PAD patients with intermittent claudication (IC; patients experience pain during activity), and patients with chronic limb threatening ischemia (CLTI; the most severe presentation of PAD -patients experience pain at rest with increased risk of ulcers, gangrene, and amputation). A similar approach was used on GA muscle sections from PAD patients before and after 3 weeks of supervised exercise. qPCR was done on flow sorted live CD56-CD31+ EC population from HA and CLTI GA muscle biopsies, for CD31 and PFKFB3 expression. Results: The IC presentation did not increase the %PFKFB3 + ECs (17.08 ± 1.19 vs. 14.40 ± 2.32 SEM, n=6-7/group, p= 0.69) from HA. However, in CLTI tissues, the %PFKFB3 + ECs increased vs both HA (42.01 ± 4.32 SEM vs. 14.40 ± 2.327 SEM, n=7/group, p= 0.0025) and IC (42.01 ± 4.32 SEM vs. 17.08 ± 1.19 SEM, n=6-7/group, p= 0.01). Furthermore, qPCR analysis of PFKFB3 expression in flow sorted CD56-CD31+ EC fraction from CLTI vs. HA (1.855 ± 0.084 SEM vs. 1 ± 0.1768 SEM, n=4/group, P= 0.0052). Three weeks of supervised exercise in PAD patients, with tolerance for activity, decreased the %PFKFB3 + ECs compared vs. pre-exercise values (7.02 ± 1.74 SEM vs. 18.24 ± 2.15 SEM, n= 4 /group, p= 0.0077) respectively. Conclusion: In humans with PAD, higher EC expression of PFKFB3 + uniquely associated with CLTI, but not the IC presentation. Supervised exercise, the only non-surgical approved method to improve functional performance and angiogenesis in PAD patients, reduced EC PFKFB3 expression.

Effects of quercetin in preclinical models of Parkinson's disease: A systematic review.

Parkinson's disease (PD) is a neurodegenerative disease that affects dopaminergic neurons, thus impairing dopaminergic signalling. Quercetin (QUE) has antioxidant and neuroprotective properties that are promising for the treatment of PD. This systematic review aimed to investigate the therapeutic effects of QUE against PD in preclinical models. The systematic search was performed in PubMed, Scopus and Web of Science. At the final screening stage, 26 articles were selected according to pre-established criteria. Selected studies used different methods for PD induction, as well as animal models. Most studies used rats (73.08%) and mice (23.08%), with 6-OHDA as the main strategy for PD induction (38.6%), followed by rotenone (30.8%). QUE was tested immersed in oil, nanosystems or in free formulations, in varied routes of administration and doses, ranging from 10 to 400 mg/kg and from 5 to 200 mg/kg in oral and intraperitoneal administrations, respectively. Overall, evidence from published data suggests a potential use of QUE as a treatment for PD, mainly through the inhibition of oxidative stress, neuroinflammatory response and apoptotic pathways.

Chemical Strategies for the Detection and Elimination of Senescent Cells.

Cellular senescence can be defined as an irreversible stopping of cell proliferation that arises in response to various stress signals. Cellular senescence is involved in diverse physiological and pathological processes in different tissues, exerting effects on processes as differentiated as embryogenesis, tissue repair and remodeling, cancer, aging, and tissue fibrosis. In addition, the development of some pathologies, aging, cancer, and other age-related diseases has been related to senescent cell accumulation. Due to the complexity of the senescence phenotype, targeting senescent cells is not trivial, is challenging, and is especially relevant for in vivo detection in age-related diseases and tissue samples. Despite the elimination of senescent cells (senolysis) using specific drugs (senolytics) that have been shown to be effective in numerous preclinical disease models, the clinical translation is still limited due to the off-target effects of current senolytics and associated toxicities. Therefore, the development of new chemical strategies aimed at detecting and eliminating senescent cells for the prevention and selective treatment of senescence-associated diseases is of great interest. Such strategies not only will contribute to a deeper understanding of this rapidly evolving field but also will delineate and inspire new possibilities for future research.In this Account, we report our recent research in the development of new chemical approaches for the detection and elimination of senescent cells based on new probes, nanoparticles, and prodrugs. The designed systems take advantage of the over-representation in senescent cells of certain biomarkers such as β-galactosidase and lipofuscin. One- and two-photon probes, for higher tissue penetration, have been developed. Moreover, we also present a renal clearable fluorogenic probe for the in vivo detection of the β-galactosidase activity, allowing for correlation with the senescent burden in living animals. Moreover, as an alternative to molecular-based probes, we also developed nanoparticles for senescence detection. Besides, we describe advances in new therapeutic agents to selectively eradicate senescent cells using β-galactosidase activity-sensitive gated nanoparticles loaded with cytotoxic or senolytic agents or new prodrugs aiming to increase the selectivity and reduction of off-target toxicities of current drugs. Moreover, new advances therapies have been applied in vitro and in vivo. Studies with the probes, nanoparticles, and prodrugs have been applied in several in vitro and in vivo models of cancer, fibrosis, aging, and drug-induced cardiotoxicity in which senescence plays an important role. We discuss the benefits of these chemical strategies toward the development of more specific and sophisticated probes, nanoparticles, and prodrugs targeting senescent cells.

Metabolic rewiring promotes anti-inflammatory effects of glucocorticoids.

Glucocorticoids represent the mainstay of therapy for a broad spectrum of immune-mediated inflammatory diseases. However, the molecular mechanisms underlying their anti-inflammatory mode of action have remained incompletely understood1. Here we show that the anti-inflammatory properties of glucocorticoids involve reprogramming of the mitochondrial metabolism of macrophages, resulting in increased and sustained production of the anti-inflammatory metabolite itaconate and consequent inhibition of the inflammatory response. The glucocorticoid receptor interacts with parts of the pyruvate dehydrogenase complex whereby glucocorticoids provoke an increase in activity and enable an accelerated and paradoxical flux of the tricarboxylic acid (TCA) cycle in otherwise pro-inflammatory macrophages. This glucocorticoid-mediated rewiring of mitochondrial metabolism potentiates TCA-cycle-dependent production of itaconate throughout the inflammatory response, thereby interfering with the production of pro-inflammatory cytokines. By contrast, artificial blocking of the TCA cycle or genetic deficiency in aconitate decarboxylase 1, the rate-limiting enzyme of itaconate synthesis, interferes with the anti-inflammatory effects of glucocorticoids and, accordingly, abrogates their beneficial effects during a diverse range of preclinical models of immune-mediated inflammatory diseases. Our findings provide important insights into the anti-inflammatory properties of glucocorticoids and have substantial implications for the design of new classes of anti-inflammatory drugs.

Fosgonimeton attenuates amyloid-beta toxicity in preclinical models of Alzheimer's disease

Positive modulation of hepatocyte growth factor (HGF) signaling may represent a promising therapeutic strategy for Alzheimer's disease (AD) based on its multimodal neurotrophic, neuroprotective, and anti-inflammatory effects addressing the complex pathophysiology of neurodegeneration. Fosgonimeton is a small-molecule positive modulator of the HGF system that has demonstrated neurotrophic and pro-cognitive effects in preclinical models of dementia. Herein, we evaluate the neuroprotective potential of fosgonimeton, or its active metabolite, fosgo-AM, in amyloid-beta (Aβ)-driven preclinical models of AD, providing mechanistic insight into its mode of action. In primary rat cortical neurons challenged with Aβ (Aβ1-42), fosgo-AM treatment significantly improved neuronal survival, protected neurite networks, and reduced tau hyperphosphorylation. Interrogation of intracellular events indicated that cortical neurons treated with fosgo-AM exhibited a significant decrease in mitochondrial oxidative stress and cytochrome c release. Following Aβ injury, fosgo-AM significantly enhanced activation of pro-survival effectors ERK and AKT, and reduced activity of GSK3β, one of the main kinases involved in tau hyperphosphorylation. Fosgo-AM also mitigated Aβ-induced deficits in Unc-like kinase 1 (ULK1) and Beclin-1, suggesting a potential effect on autophagy. Treatment with fosgo-AM protected cortical neurons from glutamate excitotoxicity, and such effects were abolished in the presence of an AKT or MEK/ERK inhibitor. In vivo, fosgonimeton administration led to functional improvement in an intracerebroventricular Aβ25-35 rat model of AD, as it significantly rescued cognitive function in the passive avoidance test. Together, our data demonstrate the ability of fosgonimeton to counteract mechanisms of Aβ-induced toxicity. Fosgonimeton is currently in clinical trials for mild-to-moderate AD (NCT04488419; NCT04886063).

Aryl hydrocarbon receptor activity in intestinal epithelial cells in the formation of colonic tertiary lymphoid tissues.

After birth, the development of secondary lymphoid tissues (SLTs) in the colon is dependent on the expression of the aryl hydrocarbon receptor (AhR) in immune cells as a response to the availability of AhR ligands. However, little is known about how AhR activity from intestinal epithelial cells (IECs) may influence the development of tertiary lymphoid tissues (TLTs). As organized structures that develop at sites of inflammation or infection during adulthood, TLTs serve as localized centers of adaptive immune responses, and their presence has been associated with the resolution of inflammation and tumorigenesis in the colon. Here, we investigated the effect of the conditional loss of AhR activity in IECs in the formation and immune cell composition of TLTs in a model of acute inflammation. In females, loss of AhR activity in IECs reduced the formation of TLTs without significantly changing disease outcomes or immune cell composition within TLTs. In males lacking AhR expression in IECs, increased disease activity index, lower expression of functional-IEC genes, increased number of TLTs, increased T-cell density, and lower B- to T-cell ratio were observed. These findings may represent an unfavorable prognosis when exposed to dextran sodium sulfate (DSS)-induced epithelial damage compared with females. Sex and loss of IEC AhR also resulted in changes in microbial populations in the gut. Collectively, these data suggest that the formation of TLTs in the colon is influenced by sex and AhR expression in IECs.NEW & NOTEWORTHY This is the first research of its kind to demonstrate a clear connection between biological sex and the development of tertiary lymphoid tissues (TLT) in the colon. In addition, the research finds that in a preclinical model of inflammatory bowel disease, the expression of the aryl hydrocarbon receptor (AhR) influences the development of these structures in a sex-specific manner.

Standard Radio-Iodine Labeling Protocols Impaired the Functional Integrity of Mesenchymal Stem/Stromal Cell Exosomes.

Mesenchymal stem/stromal cells (MSCs) are an extensively studied cell type in clinical trials due to their easy availability, substantial ex vivo proliferative capacity, and therapeutic efficacy in numerous pre-clinical animal models of disease. The prevailing understanding suggests that their therapeutic impact is mediated by the secretion of exosomes. Notably, MSC exosomes present several advantages over MSCs as therapeutic agents, due to their non-living nature and smaller size. However, despite their promising therapeutic potential, the clinical translation of MSC exosomes is hindered by an incomplete understanding of their biodistribution after administration. A primary obstacle to this lies in the lack of robust labels that are highly sensitive, capable of directly and easily tagging exosomes with minimal non-specific labeling artifacts, and sensitive traceability with minimal background noise. One potential candidate to address this issue is radioactive iodine. Protocols for iodinating exosomes and tracking radioactive iodine in live imaging are well-established, and their application in determining the biodistribution of exosomes has been reported. Nevertheless, the effects of iodination on the structural or functional activities of exosomes have never been thoroughly examined. In this study, we investigate these effects and report that these iodination methods abrogate CD73 enzymatic activity on MSC exosomes. Consequently, the biodistribution of iodinated exosomes may reflect the biodistribution of denatured exosomes rather than functionally intact ones.

Impact of conjugation to different lipids on the lymphatic uptake and biodistribution of brush PEG polymers

Delivery to peripheral lymphatics can be achieved following interstitial administration of nano-sized delivery systems (nanoparticles, liposomes, dendrimers etc) or molecules that hitchhike on endogenous nano-sized carriers (such as albumin). The published work concerning the hitchhiking approach has mostly focussed on the lymphatic uptake of vaccines conjugated directly to albumin binding moieties (ABMs such as lipids, Evans blue dye derivatives or peptides) and their subsequent trafficking into draining lymph nodes. The mechanisms underpinning access and transport of these constructs into lymph fluid, including potential interaction with other endogenous nanocarriers such as lipoproteins, have largely been ignored. Recently, we described a series of brush polyethylene glycol (PEG) polymers containing end terminal short-chain or medium-chain hydrocarbon tails (1C2 or 1C12, respectively), cholesterol moiety (Cho), or medium-chain or long-chain diacylglycerols (2C12 or 2C18, respectively). We evaluated the association of these materials with albumin and lipoprotein in rat plasma, and their intravenous (IV) and subcutaneous (SC) pharmacokinetic profiles. Here we fully detail the association of this suite of polymers with albumin and lipoproteins in rat lymph, which is expected to facilitate lymph transport of the materials from the SC injection site. Additionally, we characterise the thoracic lymph uptake, tissue and lymph node biodistribution of the lipidated brush PEG polymers following SC administration to thoracic lymph cannulated rats. All polymers had moderate lymphatic uptake in rats following SC dosing with the lymph uptake higher for 1C2-PEG, 2C12-PEG and 2C18-PEG (5.8%, 5.9% and 6.7% dose in lymph, respectively) compared with 1C12-PEG and Cho-PEG (both 1.5% dose in lymph). The enhanced lymph uptake of 1C2-PEG, 2C12-PEG and 2C18-PEG appeared related to their association profile with different lipoproteins. The five polymers displayed different biodistribution patterns in major organs and tissues in mice. All polymers reached immune cells deep within the inguinal lymph nodes of mice following SC dosing. The ability to access these immune cells suggests the potential of the polymers as platforms for the delivery of vaccines and immunotherapies. Future studies will focus on evaluating the lymphatic targeting and therapeutic potential of drug or vaccine-loaded polymers in pre-clinical disease models.

Mitophagy modulation for the treatment of cardiovascular diseases.

Defects of mitophagy, the selective form of autophagy for mitochondria, are commonly observed in several cardiovascular diseases and represent the main cause of mitochondrial dysfunction. For this reason, mitophagy has emerged as a novel and potential therapeutic target. In this review, we discuss current evidence about the biological significance of mitophagy in relevant preclinical models of cardiac and vascular diseases, such as heart failure, ischemia/reperfusion injury, metabolic cardiomyopathy and atherosclerosis. Multiple studies have shown that cardiac and vascular mitophagy is an adaptive mechanism in response to stress, contributing to cardiovascular homeostasis. Mitophagy defects lead to cell death, ultimately impairing cardiac and vascular function, whereas restoration of mitophagy by specific compounds delays disease progression. Despite previous efforts, the molecular mechanisms underlying mitophagy activation in response to stress are not fully characterized. A comprehensive understanding of different forms of mitophagy active in the cardiovascular system is extremely important for the development of new drugs targeting this process. Human studies evaluating mitophagy abnormalities in patients at high cardiovascular risk also represent a future challenge.

BET inhibitor nanotherapy halts kidney damage and reduces chronic kidney disease progression after ischemia-reperfusion injury

Targeting epigenetic mechanisms has emerged as a potential therapeutic approach for the treatment of kidney diseases. Specifically, inhibiting the bromodomain and extra-terminal (BET) domain proteins using the small molecule inhibitor JQ1 has shown promise in preclinical models of acute kidney injury (AKI) and chronic kidney disease (CKD). However, its clinical translation faces challenges due to issues with poor pharmacokinetics and side effects. Here, we developed engineered liposomes loaded with JQ1 with the aim of enhancing kidney drug delivery and reducing the required minimum effective dose by leveraging cargo protection. These liposomes efficiently encapsulated JQ1 in both the membrane and core, demonstrating superior therapeutic efficacy compared to freely delivered JQ1 in a mouse model of kidney ischemia-reperfusion injury. JQ1-loaded liposomes (JQ1-NPs) effectively targeted the kidneys and only one administration, one-hour after injury, was enough to decrease the immune cell (neutrophils and monocytes) infiltration to the kidney—an early and pivotal step to prevent damage progression. By inhibiting BRD4, JQ1-NPs suppress the transcription of pro-inflammatory genes, such as cytokines (il-6) and chemokines (ccl2, ccl5). This success not only improved early the kidney function, as evidenced by decreased serum levels of BUN and creatinine in JQ1-NPs-treated mice, along with reduced tissue expression of the damage marker, NGAL, but also halted the production of extracellular matrix proteins (Fsp-1, Fn-1, α-SMA and Col1a1) and the fibrosis development. In summary, this work presents a promising nanotherapeutic strategy for AKI treatment and its progression and provides new insights into renal drug delivery.

Mouse mucosal-associated invariant T cell receptor recognition of MR1 presenting the vitamin B metabolite, 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil

Mucosal-associated invariant T (MAIT) cells can elicit immune responses against riboflavin-based antigens presented by the evolutionary conserved MHC class I related protein, MR1. While we have an understanding of the structural basis of human MAIT cell receptor (TCR) recognition of human MR1 presenting a variety of ligands, how the semi-invariant mouse MAIT TCR binds mouse MR1-ligand remains unknown. Here, we determine the crystal structures of 2mouse TRAV1-TRBV13-2+ MAIT TCR-MR1-5-OP-RU ternary complexes, whose TCRs differ only in the composition of their CDR3β loops. These mouse MAIT TCRs mediate high affinity interactions with mouse MR1-5-OP-RU and cross-recognize human MR1-5-OP-RU. Similarly, a human MAIT TCR could bind mouse MR1-5-OP-RU with high affinity. This cross-species recognition indicates the evolutionary conserved nature of this MAIT TCR-MR1 axis. Comparing crystal structures of the mouse versus human MAIT TCR-MR1-5-OP-RU complexes provides structural insight into the conserved nature of this MAIT TCR-MR1 interaction and conserved specificity for the microbial antigens, whereby key germline-encoded interactions required for MAIT activation are maintained. This is an important consideration for the development of MAIT cell-based therapeutics that will rely on preclinical mouse models of disease.

Abstract 7: Ginsenoside Rb1 delays the senescence of CD8+ T cells to expand T cells with superior antitumor immunity

Abstract Background and Objective: Immunosenescence represents a distinct state of T cell dysfunction in the TME, and plays crucial role in many age-related diseases including tumor. Senescent cell removal by senolytic agents or therapies that inhibit the SASP have demonstrated benefit in both preclinical and clinical models of geriatric decline and chronic diseases. Here, we aimed to screen anti-aging compounds to delay T-cell senescence in TME, and explore novel strategies of reversing tumor induced T-cell senescence to restore antitumor immunity. Methods and Results: Using in vitro senescence inducing system, we screened ginsenoside Rb1 from 22 anti-aging compounds as the compound that had the most effective activity to reduce CD8+ T cell senescence, displayed as decreased β-gal, p16, and p21. Further analysis showed that ginsenoside Rb1 promoted anti-CD3/CD28-induced TCR signaling and the secretion of effector cytokines IFN-γ, TNF-α and IL -2 in OTI T cells. Intriguingly, ginsenoside Rb1 treatment significantly increased TCF-1 in CD8+ T cells, and ginsenoside Rb1 treated OT-I T cells significantly inhibited tumor growth. Moreover, ginsenoside Rb1 greatly enhanced the efficiency of CD19-CART cells to kill Namalwa tumor cells. Conclusion: Ginsenoside Rb1 delays T cell senescence and enhances T cell antitumor activity. This data provides a new insight into T cell based antitumor therapy. Citation Format: Chunhong Ma, Xue Sheng, Chunyang Li. Ginsenoside Rb1 delays the senescence of CD8+ T cells to expand T cells with superior antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7.

Abstract 4183: Utility of the highly immunodeficient SRG rat for combined drug efficacy, pharmacokinetics, and toxicology studies in tumor-bearing animals

Abstract Immunodeficient rodents are vital pre-clinical disease models. Historically, immunodeficient mice have been standard for hosting human cell and tissue xenografts, enabling cancer drug efficacy and tolerability testing. However, an immunodeficient rat that supports a variety of human cancer types provides a larger model for easier surgical manipulation and serial blood and tumor tissue sampling, allowing for efficacy, pharmacokinetics, and toxicology testing in the same animal. We created a Sprague Dawley Rag2 -/-, Il2rg -/- rat (SRG Rat®; SRG) that is highly supportive of human cell and tissue engraftment. The SRG rat lacks B, T, and NK cells and is more immunodeficient than the Nude rat. Here we show comparative pathology between the SRG rat and its parental strain, the CRL Sprague Dawley (CD). We also present data from an efficacy study in tumor bearing SRG rats, demonstrating that serial blood draws and tumor biopsies can be performed in tumor bearing animals to assess drug pharmacokinetics and pharmacodynamics within a single study. First, we assessed 10 SRG (5/sex) and 10 CD (5/sex) at 8-10 weeks of age. Body weight, hematology, and clinical chemistry parameters were measured. Microscopic examinations were performed on routine H&E slide preparations. Male and female SRG displayed lower mean body weight when compared to sex- and age-matched CD. Compared to CD, SRG had reduced lymphoid tissue and circulating monocytes, and highly reduced circulating lymphocytes, neutrophils, eosinophils, and basophils; expected phenotypes for this severely immunodeficient rat. Thymus was not present in SRG rats, spleens were grossly smaller, and bone marrow cellularity was decreased compared to CD. Microscopically, mandibular lymph nodes and lymphoid tissue in spleen, lung, and intestine were not observed in SRG rats, consistent with the 92% decrease in circulating lymphocytes. To demonstrate the utility of the SRG for tumor inhibition, pharmacokinetics, and pharmacodynamics, we inoculated rats with human VCaP prostate cancer cell-derived tumors, then treated these animals and collected serial blood samples and tumor biopsies to assess tumor biomarkers. Treatment led to decreased PSA and AR, two key proteins expressed in prostate cancer, correlating to decreased tumor growth. These data demonstrate that the SRG rat is suitable for toxicology studies and has comparable pathology to the CD rat, except for reduced lymphoid tissue and WBCs, which are expected phenotypes. In addition, the SRG rat supports the growth of human cancer tissue for treatment studies. The large size of the SRG rat and comparative pathology to the CD rat support its value as an immunodeficient model for assessing toxicity during efficacy testing for de-risking safety concerns in the presence of the human target tissue. Citation Format: Diane Begemann, Cynthia Dunn, Darrell Robertson, Lauren Keach, Emily Baldwin, R. Grace Walton, Alex Van Engelenburg, Jessica Durrant, Laura Healy, Koh Meng Aw Yong, Michael J. Schlosser, Fallon K. Noto. Utility of the highly immunodeficient SRG rat for combined drug efficacy, pharmacokinetics, and toxicology studies in tumor-bearing animals [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4183.