Biology subjects

Ingersoll, M. A.

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

17 recordsLinked to original sources

bioRxiv2026

A cilia-dependent inflammatory programme links bacterial detection to kidney disease

The primary cilium is a microtubule-based sensory organelle projecting from the plasma membrane of most mammalian cells. Genetic defects in ciliary components cause chronic kidney disease (CKD) characterized by heightened production of inflammatory and fibrogenic mediators by tubular epithelial cells. Yet, whether this reflects a physiological role of the primary cilium remains unknown. Here, we show that primary cilia on kidney tubular cells bind uropathogenic Escherichia coli and, in response to bacterial components, initiate a fibro-inflammatory program reminiscent of CKD. Integrating single-cell transcriptomics with conditional mouse models, we observed that epithelial cilia orchestrate a similar fibro-inflammatory response in the absence of infection during CKD. This convergence reveals a shared cilia-dependent signalling axis governing both host-pathogen responses and CKD progression. Mechanistically, cilia ablation selectively impairs tubular responses to ADP-heptose, a pathogen-associated molecular pattern that activates NF-{kappa}B via the cytosolic innate immune receptor ALPK1. In human kidney organoids, ADP-heptose induces robust fibro-inflammation, and genetic or pharmacological inhibition of ALPK1 attenuates this response in a rodent CKD model. Together, these findings identify primary cilia as central orchestrators of a fibro-inflammatory program linking pathogen detection to kidney disease progression.

physiology↗

bioRxiv2025

The DanRI regulatory system in uropathogenic Escherichia coli subverts neutrophil responses

Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTI). To establish an infection, UPEC must evade infiltrating neutrophils and their antimicrobial neutrophil extracellular traps (NETs). In this study, we identify a previously uncharacterized two-gene regulatory system within the pathogenicity island PAIUTI89II, which we named DanRI (Defense against neutrophil Regulator and Inhibitor). DanRI is induced by nucleosomes present in NETs and enables UPEC to suppress neutrophil responses by attenuating reactive oxygen species production and NET formation. Mechanistically, DanI functions as an antagonist to the transcriptional regulator DanR, thereby modulating key bacterial processes, including metabolic processes, flagellar biosynthesis, and stress response pathways. DanRI is required for UPEC fitness and long-term persistence in a mouse model of UTI. Taken together, our findings reveal DanRI as a novel regulatory system that promotes UPEC pathogenesis through immune evasion. Graphical abstract and model O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/658900v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@19095e6org.highwire.dtl.DTLVardef@1613c26org.highwire.dtl.DTLVardef@b415c3org.highwire.dtl.DTLVardef@100b79e_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2025

Oral OM-89 in combination with antibiotics prevents recurrent infection in a mouse model of urinary tract infection

Urinary tract infection (UTI) is a very common infection. Approximately 25% of all women will experience recurrent infection, defined by 2 UTI in 6 months or 3 UTI in a 12 month period. Recurrent infection is thought to be due in part to the development of local bacterial reservoirs in the bladder after an infection. These reservoirs are undetected by the host immune system and may re-emerge after resolution of the primary infection. Frequently, recurrent UTI require repeated antibiotic use, leading to the development of resistance, and negatively impacting the quality of life of the patient. Given the rise in multidrug resistant uropathogens, treatments that do not rely upon antibiotics are urgently needed for this patient population. We assessed the capacity of a lyophilized E. coli extract, OM-89(R), as a preventive measure to reduce the incidence of spontaneous recurrence in a mouse cystitis model. Administration of OM-89 per os after the initiation of an acute UTI significantly reduced the number of spontaneous recurrent UTI in female mice over a 1 month follow-up period only when the animals were also treated with antibiotics. Protection against recurrent UTI arose quickly and without changes in any adaptive immune response parameter measured, ruling out a role for OM-89 in augmenting adaptive immunity to protect against spontaneous recurrent UTI in the first month of use.

immunology↗

bioRxiv2024

A simple ex vivo bladder infection model permits study of host-pathogen interactions in UTI

Urinary tract infections (UTI) are one of the most common infections, worldwide. To understand mechanisms of UTI pathogenesis and find new treatments, researchers often use animal models, such as mice or rats. However, studying certain phenotypes in animals can be difficult. Additionally, using animals in research comes with significant administrative and ethical challenges. To address these challenges, we developed a simple, reproducible, and cost-effective model to study UTI using donated mouse bladder tissue that would otherwise be discarded. This model allows researchers of all experience levels to study interactions between the host and pathogen in a controlled environment. We tested uropathogenic E. coli colonization and invasion of isolated urothelial sheets from 30 minutes to 24 hours, finding that bacterial burden in our ex vivo model was comparable to in vivo UTI mouse models. To optimize reproducibility, we tested multiple variables, including technical parameters, such as incubator conditions, and biological factors, such as biological sex or prior pregnancy in the donor mouse. This method offers several advantages, including assessment of early host-pathogen interactions, immune cell uptake of bacteria, the impact of age and sex of donor animals in infection, and diverse bacterial strains, mutants, or treatments. In addition, in some countries, sharing material recovered from animals sacrificed for other reasons does not require additional ethical approval by the receiving laboratory, providing a resource for labs without access to animals and reducing administrative burden. Given the breadth of the model with respect to sex, age, mouse and bacterial strain, and the ability to test any parameter that can be included in a 96-well plate, we believe this model will be useful to UTI researchers, with potential application beyond infection or even beyond the bladder to other tissues.

immunology↗

bioRxiv2024

Bacterial growth under confinement requires transcriptional adaptation to resist metabolite-induced turgor pressure build-up

Bacterial proliferation often occurs in confined spaces, during biofilm formation, within host cells, or in specific niches during infection, creating mechanical constraints. We investigated how spatial confinement and growth-induced mechanical pressure affect bacterial physiology. Here, we found that, when proliferating in a confining microfluidic-based device with access to nutrients, Escherichia coli cells generate forces in the hundreds of kPa range. This pressure decouples growth and division, producing shorter bacteria with higher protein concentrations. This leads to cytoplasmic crowding, which ultimately arrests division and stalls protein synthesis. In this arrested state, the pressure produced by bacteria keeps increasing. A minimal theoretical model of bacterial growth predicts this novel regime of steady pressure increase in the absence of protein production, that we named overpressurization. In this regime, the Rcs pathway is activated and that abnormal shapes appear in rcs mutant populations only when they reach the overpressurized state. A uropathogenic strain of E. coli displayed the same confined growth phenotypes in vitro and requirement for Rcs in a mice model of urinary tract infection, suggesting that these pressurized regimes are relevant to understand the physiopathology of bacterial infections.

microbiology↗

bioRxiv2024

FDA-Approved MEK1/2 Inhibitor, Trametinib, Protects Mice from Cisplatin and Noise-Induced Hearing Loss

Hearing loss is one of the most common types of disability; however, there is only one FDA-approved drug to prevent any type of hearing loss. Treatment with the highly effective chemotherapy agent, cisplatin, and exposure to high decibel noises are two of the most common causes of hearing loss. The mitogen activated protein kinase (MAPK) pathway, a phosphorylation cascade consisting of RAF, MEK1/2, and ERK1/2, has been implicated in both types of hearing loss. Pharmacologically inhibiting BRAF or ERK1/2 is protective from noise and cisplatin-induced hearing loss in multiple mouse models. Trametinib, a MEK1/2 inhibitor, protects from cisplatin induced outer hair cell death in mouse cochlear explants; however, to the best of our knowledge, inhibiting MEK1/2 has not yet been shown to be protective from hearing loss in vivo. In this study, we demonstrate that trametinib protects from cisplatin-induced hearing loss in a translationally relevant mouse model and does not interfere with cisplatins tumor killing efficacy in cancer cell lines. Higher doses of trametinib were toxic to mice when combined with cisplatin but lower doses of the drug were protective from hearing loss without any known toxicity. Trametinib also protected mice from noise-induced hearing loss and synaptic damage. This study shows that MEK1/2 inhibition protects from both insults of hearing loss and that targeting all three kinases in the MAPK pathway protect from cisplatin and noise-induced hearing loss in mice.

neuroscience↗

bioRxiv2024

Oseltamivir (Tamiflu), a Commonly Prescribed Antiviral Drug, Mitigates Hearing Loss in Mice

Hearing loss affects up to 10% of all people worldwide, but currently there is only one FDA-approved drug for its prevention in a subgroup of cisplatin-treated pediatric patients. Here, we performed an unbiased screen of 1,300 FDA-approved drugs for protection against cisplatin-induced cell death in an inner ear cell line, and identified oseltamivir phosphate (brand name Tamiflu), a common influenza antiviral drug, as a top candidate. Oseltamivir phosphate was found to be otoprotective by oral delivery in multiple established cisplatin and noise exposure mouse models. The drug conferred permanent hearing protection of 15-25 dB SPL for both female and male mice. Oseltamivir treatment reduced in mice outer hair cells death after cisplatin treatment and mitigated cochlear synaptopathy after noise exposure. A potential binding protein, ERK1/2, associated with inflammation, was shown to be activated with cisplatin treatment and reduced by oseltamivir cotreatment in cochlear explants. Importantly, the number of infiltrating immune cells to the cochleae in mice post noise exposure, were significantly reduced with oseltamivir treatment, suggesting an anti-inflammatory mechanism of action. Our results support oseltamivir, a widespread drug for influenza with low side effects, as a promising otoprotective therapeutic candidate in both cisplatin chemotherapy and traumatic noise exposure.

neuroscience↗

bioRxiv2023

KSR1 Knockout Mouse Model Demonstrates MAPK Pathway's Key Role in Cisplatin- and Noise-induced Hearing Loss

Hearing loss is a major disability in everyday life and therapeutic interventions to protect hearing would benefit a large portion of the world population. Here we found that mice devoid of the protein kinase suppressor of RAS 1 (KSR1) in their tissues (germline KO mice) exhibit resistance to both cisplatin- and noise- induced permanent hearing loss compared to their wild-type KSR1 littermates. KSR1 is expressed in the cochlea and is a scaffold protein that brings in proximity the mitogen-activated protein kinase (MAPK) proteins BRAF, MEK and ERK and assists in their activation through a phosphorylation cascade induced by both cisplatin and noise insults in the cochlear cells. Deleting the KSR1 protein tempered down the MAPK phosphorylation cascade in the cochlear cells following both cisplatin and noise insults and conferred hearing protection of up to 30 dB SPL in three tested frequencies in mice. Treatment with dabrafenib, an FDA- approved oral BRAF inhibitor, downregulated the MAPK kinase cascade and protected the KSR1 wild-type mice from both cisplatin- and noise-induced hearing loss. Dabrafenib treatment did not enhance the protection of KO KSR1 mice, as excepted, providing evidence dabrafenib works primarily through the MAPK pathway. Thus, either elimination of the KSR1 gene expression or drug inhibition of the MAPK cellular pathway in mice resulted in profound protection from both cisplatin- and noise-induce hearing loss. Inhibition of the MAPK pathway, a cellular pathway that responds to damage in the cochlear cells, can prove a valuable strategy to protect and treat hearing loss. Significance StatementTen percent of the world population suffers from hearing loss but this impairment may be preventable. We show that mice devoid of the KSR1 protein (KO) exhibit resistance to cisplatin- and noise-induced permanent hearing loss compared to wild-type littermates that harbor the protein. Removing KSR1 tempers down the MAPK phosphorylation cascade of BRAF-MEK-ERK induced in the cochlea following cisplatin and noise insults. Treatment of KSR1 wild-type mice following cisplatin or noise with an FDA-approved BRAF inhibitor, dabrafenib, protected the hearing and, importantly, did not confer additional protection to the KO KSR1 mice. Hence, the MAPK pathway has a unique role in responding to cochlear damage, and removing KSR1 gene expression or drug inhibition of the pathway results in hearing protection.

neuroscience↗

bioRxiv2023

ERK1/2 Inhibition Alleviates Noise-Induced Hearing Loss While Tempering Down the Immune Response

Noise-induced hearing loss (NIHL) is a major cause of hearing impairment, yet no FDA-approved drugs exist to prevent it. Targeting the mitogen activated protein kinase (MAPK) cellular pathway has emerged as a promising approach to attenuate NIHL. Tizaterkib is an orally bioavailable, highly specific ERK1/2 inhibitor, currently in Phase-1 anticancer clinical trials. Here, we tested tizaterkibs efficacy against permanent NIHL in mice at doses equivalent to what humans are currently prescribed in clinical trials. The drug given orally 24 hours after noise exposure, protected an average of 20-25 dB SPL in three frequencies, in female and male mice, had a therapeutic window >50, and did not confer additional protection to KSR1 genetic knockout mice, showing the drug works through the MAPK pathway. Tizaterkib shielded from noise-induced cochlear synaptopathy, and a 3-day, twice daily, treatment with the drug was the optimal determined regimen. Importantly, tizaterkib was shown to decrease the number of CD45 and CD68 positive immune cells in the cochlea following noise exposure, which could be part of the protective mechanism of MAPK inhibition.

neuroscience↗

bioRxiv2021

Bladder tissue-resident memory T cells are necessary and sufficient to mediate immunity to recurrent UTI

Urinary tract infection (UTI) is one of the most prevalent human bacterial infections. New therapeutic approaches, including vaccination and immunotherapy, are urgently needed to combat the rapid global dissemination of multidrug-resistant uropathogens. Development of therapies is impeded by an incomplete understanding of memory development during UTI. Here, we found that reducing bacterial load early in infection, by reducing the inoculum or with antibiotics after infection, completely abrogated the protective memory response. We observed a mixed T helper cell polarization, comprised of Th1, Th2, and Th17 T cells, among T cells infiltrating the bladder during primary infection. Thus, we hypothesized that reducing antigen load altered T helper cell polarization leading to poor memory. Surprisingly, however, T helper cell polarization was unchanged in these scenarios. Instead, we uncovered a population of tissue resident memory (TRM) T cells that was significantly reduced in the absence of sufficient antigen. Demonstrating that TRM cells are necessary for immune memory, transfer of lymph node or spleen-derived infection-experienced T cells to naive animals did not confer protection against infection. Supporting that TRM cells are sufficient to protect against recurrent UTI, animals depleted of systemic T cells, or treated with FTY720 to block memory lymphocyte migration from lymph nodes to infected tissue, were equally protected compared to unmanipulated mice against a second UTI. Thus, we uncovered an unappreciated key role for TRM cells in the memory response to bacterial infection in this mucosa, providing a target for non-antibiotic-based immunotherapy and/or new vaccine strategies to prevent recurrent UTI. One Sentence SummaryTRM are necessary and sufficient for memory to recurrent UTI

immunology↗

bioRxiv2021

Macrophages in the uterus are functionally specialised and continually replenished from the circulation

Macrophages are innate immune cells that fight infection but also regulate tissue regeneration and remodelling. In the uterus, although tissue remodelling is essential for establishment and maintenance of pregnancy, the specialisation of macrophages is not well characterised compared to other mucosal tissues. Here we show that uterine macrophages are functionally specialised, expressing multiple markers of alternative activation associated with tissue remodelling and repair, and responding more highly to the type 2 cytokine IL-4 than other mucosal tissue macrophages. Uterine macrophages were continuously replenished from circulating bone marrow-derived CCR2+ monocytes that fluctuated dramatically in number throughout the reproductive cycle, and had properties distinct from the macrophages that they became, including differential responses to microbial stimulation. Importantly, many of these properties of uterine monocytes and macrophages were conserved between mice and humans. These findings further our understanding of immune regulation of uterine tissue integrity and have important implications for differences in immune responses to infections at different phases of the reproductive cycle. SUMMARYUterine macrophages are specialised, alternatively activated cells that are replenished from circulating bone marrow-derived monocytes. Monocyte and macrophage properties fluctuate markedly throughout the reproductive cycle, with many features conserved between mice and humans, and exhibiting differential responses to microbial stimulation.

immunology↗

bioRxiv2020

Identification of sex differences in tumor-specific T cell infiltration in bladder tumor-bearing mice treated with BCG immunotherapy

Bladder cancer is the fourth most common cancer for men. However, women are often diagnosed with later stage disease and have poorer outcomes. Whether immune-based sex differences contribute to this discrepancy is unclear. In addition, models to investigate tumor-specific immunity in bladder cancer, in the context of tumor development or response to therapy, are lacking. To address this specific unmet need, we incorporated a commonly used model antigen, ovalbumin, into two well-established models of bladder cancer; the orthotopic MB49 cell line model and the carcinogenic BBN bladder cancer model. We tested the utility of these models to investigate tumor-specific immunity in the context of immunotherapy in both sexes. We found that BCG vaccination, prior to weekly BCG instillation does not impart an immune-specific benefit to tumor-bearing mice in the context of multiple BCG instillations. Furthermore, tumors developed in the testes in male mice, precluding the use of the MB49 model to directly investigate sex-based immune differences. In the BBN model, we observed that more tumor antigen-specific CD8+ T cells infiltrated male bladders compared to female bladders in the context of BCG immunotherapy and that these cells had the highest levels of the exhaustion marker PD-1. We propose our modified BBN model will contribute to our understanding of how tumor-specific immunity arises in bladder cancer. Additionally, the BBN bladder cancer model may help to uncover sex differences in tumor-specific immunity, which would provide valuable information for the development of new treatments or combination therapies for bladder cancer in women and men.

immunology↗

bioRxiv2020

A Whole Cell Metal-Organic Framework Encapsulated Vaccine Against Septicemic UPEC Infection

The increasing rate of resistance of bacterial infection against antibiotics requires next generation approaches to fight potential pandemic spread. The development of vaccines against pathogenic bacteria has been difficult owing, in part, to the genetic diversity of bacteria. Hence, there are many potential target antigens and little a priori knowledge of which antigen/s will elicit protective immunity. The painstaking process of selecting appropriate antigens could be avoided with whole-cell bacteria; however, whole-cell formulations typically fail to produce long-term and durable immune responses. These complications are one reason why no vaccine against any type of pathogenic E. coli has been successfully clinically translated. As a proof of principle, we demonstrate a method to enhance the immunogenicity of a model pathogenic E. coli strain by forming a slow releasing depot. The E. coli strain CFT073 was biomimetically mineralized within a metal-organic framework (MOF). This process encapsulates the bacteria within 30 minutes in water and at ambient temperatures. Vaccination with this new formulation substantially enhances antibody production and results in significantly enhanced survival in a mouse model of bacteremia compared to standard inactivated formulations.

immunology↗

bioRxiv2020

Functionally distinct resident macrophage subsets differentially shape responses to infection in the bladder

Resident macrophages are abundant in the bladder, playing key roles in immunity to uropathogens. Yet, whether they are heterogeneous, where they come from, and how they respond to infection remain largely unknown. We identified two macrophage subsets in mouse bladders, MacM in the muscle and MacL in the lamina propria, with distinct protein expression and transcriptomes. Using a urinary tract infection model, we validated our transcriptomic analyses, finding that MacM macrophages phagocytosed more bacteria and polarized to a more anti-inflammatory profile, whereas the MacL subset died rapidly during infection. During resolution, monocyte-derived cells contributed to tissue-resident macrophage pools and both subsets acquired transcriptional profiles distinct from naive macrophages. Depletion of these altered macrophages resulted in the induction of a type 1 biased immune response to a second urinary tract infection, improving bacterial clearance. Our study uncovers the biology of resident macrophages and their response to an exceedingly common infection in a largely overlooked organ, the bladder.

immunology↗

bioRxiv2020

The immune system fails to mount a protective response to Gram-positive or Gram-negative bacterial prostatitis

Bacterial prostatitis affects 1% of men, with increased incidence in the elderly. It is defined by the frequency and urgency to urinate, localized pain, and positive bacterial cultures in expressed seminal fluids. Acute bacterial prostatitis frequently progresses to chronicity, which is marked by recurrent acute episodes interspersed with asymptomatic periods of variable duration. Up to 80% of bacterial prostatitis cases are caused by Gram-negative uropathogenic E. coli (UPEC) or Gram-positive E. faecalis. Antibiotic treatment is standard of care, however, global dissemination of antimicrobial resistant uropathogens threatens efficacy of therapy. Thus, development of non-antibiotic-based approaches to treat bacterial prostatitis is a priority. One challenge is that the immune response to infection in the prostate is incompletely understood. We used a mouse model of transurethral bacterial instillation to study the immune response to UPEC or E. faecalis prostate infection. Both uropathogens exhibited tropism for the prostate over the bladder early post-infection. UPEC infection induced greater proinflammatory cytokine expression and neutrophil and monocyte infiltration compared to E. faecalis infection. Following challenge infection, cytokine responses and myeloid cell infiltration were largely comparable to primary infection. Characteristic of memory responses, more lymphoid cells infiltrating the prostate in the second infection compared to the primary infection. Unexpectedly, however, bacterial burden in prostates challenged with either UPEC or E. faecalis was equal or greater than in primary infection, despite that an adaptive response to UPEC infection was evident in the bladder of the same animals. Thus, an immune response to primary infection is initiated, however it does not protect against reinfection. Our findings support the idea that chronic or recurrent prostatitis develops in the absence of efficacious immunity to infection. A greater understanding of the mechanisms underlying this observation may point to actionable targets for immunotherapy.

immunology↗

bioRxiv2018

Sex differences in IL-17 determine chronicity in male versus female urinary tract infection

Sex-based differences influence incidence and outcome of infectious disease. Women have a significantly greater incidence of urinary tract infection (UTI) than men, yet, conversely, male UTI is more persistent with greater associated morbidity. Mechanisms underlying these sex-based differences are unknown, in part due to a lack of experimental models. We optimized a model to transurethrally infect male mice and directly compared UTI in both sexes. Although both sexes were initially equally colonized by uropathogenic E. coli, only male and testosterone-treated female mice remained chronically infected for up to 4 weeks. Female mice had more robust innate responses, including higher IL-17 expression, and increased {gamma}{delta} T and LTi-like cells in the bladder following infection. Accordingly, neutralizing IL-17 abolished resolution in female mice, identifying the cytokine pathway necessary for bacterial clearance. Our findings support the concept that sex-based responses to UTI contribute to impaired innate immunity in males and provide a rationale for non-antibiotic-based immune targeting to improve the response to UTI.\n\nOne Sentence SummaryWe investigated mechanisms underlying the clinical observation that while urinary tract infection is more prevalent in women, it is more severe in men, observing that in contrast to robust immune responses characterized by IL-17 in female animals, male mice develop chronic infection, following a failure to initiate innate immunity.

immunology↗

bioRxiv2017

Enterococcus faecalis Promotes Innate Immune Suppression And Polymicrobial Catheter-Associated Urinary Tract Infection

Enterococcus faecalis, a member of the human gastrointestinal microbiota, is an opportunistic pathogen associated with hospital-acquired wound, bloodstream, and urinary tract infections. E. faecalis can subvert or evade immune-mediated clearance, although the mechanisms are poorly understood. In this study, we examined E. faecalis-mediated subversion of macrophage activation. We observed that E. faecalis actively prevents NF-{kappa}B signaling in mouse RAW264.7 macrophages in the presence of Toll-like receptor agonists and during polymicrobial infection with Escherichia coli. E. faecalis and E. coli co-infection in a mouse model of catheter-associated urinary tract infection (CAUTI) resulted in a suppressed macrophage transcriptional response in the bladder compared to E. coli infection alone. Finally, we demonstrated that co-inoculation of E. faecalis with E. coli into catheterized bladders significantly augmented E. coli CAUTI. Taken together, these results support that E. faecalis suppression of NF-{kappa}B-driven responses in macrophages promotes polymicrobial CAUTI pathogenesis.\n\nAuthor SummarySynergistic polymicrobial infections can contribute to both disease severity and persistence. Enterococcus faecalis and Escherichia coli are frequently co-isolated from polymicrobial urinary tract infections. Immunomodulation by co-infecting microbes can result in a more permissive environment for pathogens to establish infection. Presently, we do not yet understand how these microbes overcome host immunity to establish polymicrobial infections. To address this, we investigated how the immunosuppressive function of E. faecalis can contribute to acute infection. We defined that E. faecalis is able to suppress macrophages in vitro, despite the presence of E. coli. We also demonstrated E. faecalis ability to augment E. coli titers in vivo to establish kidney infection. Our findings raise the prospect that E. faecalis can alter host immunity to increase susceptibility to other uropathogens.

microbiology↗