Biology subjects

McDermott, A.

Publications and source records attributed to McDermott, A..

9 recordsLinked to original sources

bioRxiv2026

Late gestational exposure to flutamide alters stromal composition and immune landscape in the rat mammary gland during pre-puberty, peri-puberty, and adulthood

Perinatal development of the mammary gland is regulated by hormonal signals that influence cell proliferation, extracellular matrix remodeling, immune cell recruitment, and intracellular signaling. While the role of estrogen in mammary gland development is well established, the impact of androgens remains less understood. To address this gap, we inhibited androgen signaling in utero using the anti-androgen flutamide (FLU) and investigated the effects on mammary gland development in rats. Using an integrative strategy combining histology, transcriptomics, lipidomics, cytokine profiling, and high-resolution imaging, mammary tissue were analyzed at pre-puberty (postnatal days (PND) 21), peri-puberty (PND46), and adulthood (PND9O). FLU exposure induced subtle, yet significant, alterations in mammary morphology and molecular signatures. At PND2l, the FLU exposed group exhibited an increased number of adipocytes with reduced size. Transcriptomic analysis revealed differentially expressed genes at PND2l and enrichment in pathways related to androgen response and immune signaling, but minimal changes at later developmental stages. Lipidomic profiling showed transient disruption in long-chain fatty acid composition at early developmental stages. Cytokine profiling revealed a reduced adaptive immune response at PND46 and PND9O, and second harmonic generation imaging demonstrated changes in collagen fiber orientation and density across all developmental stages. These data indicate that prenatal androgen signaling is essential for proper stromal development and the establishment of early transcriptional networks in the mammary gland, with only minor long-term effects on glandular architecture in adult nulliparous females.

pharmacology and toxicology↗

bioRxiv2025

ER oxidoreductin-1α and unfolded protein response as sex-dependent drivers of cardiorenal dysfunction in experimental autoimmune encephalomyelitis

BackgroundMultiple sclerosis (MS) is associated with increased cardiovascular and renal morbidity, but mechanisms linking CNS autoimmunity to peripheral organ injury remain poorly defined. We tested the hypothesis that experimental autoimmune encephalomyelitis (EAE) induces cardiorenal dysfunction via sex-specific dysregulation of endoplasmic reticulum (ER) oxidoreductases and unfolded protein response (UPR) signaling. MethodsAdult female and male C57BL/6J mice [10-12 weeks] and IRE1C148S knock-in mice underwent non-pertussis toxin EAE (nPTX-EAE) induced with 100{micro}g MOG35-55 in CFA and 200{micro}g heat-inactivated MTB with a booster at 7 days. Controls received all components except MOG. Motor scoring was done daily and EN460 (ERO1 inhibitor, 10 mg/kg IP) was given twice weekly beginning at 10DPI. Echocardiography and renal Doppler (Vevo 2100) were performed at 36-38DPI with primary outcomes of LV systolic/diastolic function and renal perfusion with tissue collected at 40DPI. LV and kidney were analyzed via western blot for ERO1, PDIA1, Prdx4, 4HNE, and BiP. Data are expressed as mean {+/-} SEM with two-way ANOVA/Tukeys post hoc or Mann Whitney test performed and outliers identified by ROUT (Q=1%). ResultsSixty-seven percent of immunized mice developed motor deficits. At 36-38DPI, EAE reduced ejection fraction and fractional shortening while increasing IVCT, IVRT, and myocardial performance index without hypertrophy. Renal resistive index increased and end-diastolic velocity decreased in addition to reduced Bowmans space at 40DPI. Females showed upregulated LV ERO1 and 4HNE while males exhibited reduced PDI and Prdx4 paired with elevated BiP. EN460 attenuated cardiac and renal dysfunction and lowered LV ERO1/4HNE in females, but not males. IRE1C148S mitigated cardiac dysfunction in males and restore renal indices in both sexes. ConclusionsnPTX-EAE causes clinically relevant, sex-specific cardiorenal dysfunction linked to distinct ER stress/UPR alterations. ERO1 inhibition protects females, whereas enhanced IRE1 activity protects males and kidneys across sexes, supporting sex-specific ER stress-targeted therapies for MS-associated cardiorenal disease.

molecular biology↗

bioRxiv2025

An in utero exposure to the synthetic estrogen diethylstilbestrol affects the fat pad composition in post-natal mammary glands

In utero exposure to the synthetic estrogen diethylstilbestrol (DES) has been linked to developmental abnormalities and elevated breast cancer risk in adulthood in human and rodent models. While the impact of DES on the mammary epithelium has been thoroughly investigated, its effect on the other cell types of the mammary gland remains understudied. Here, given that the mammary gland development is strongly associated with its microenvironment, we aimed to investigate how in utero DES exposure alters the mammary glands stromal and immune function across key developmental stages. To achieve this aim, timed-pregnant rats were gavaged daily with DES or vehicle from gestation days 16-21, and female offspring mammary glands were analyzed at pre-puberty (postnatal day 21 (PDN21)), puberty (PND46), and adulthood (PND90). We assessed morphological and extracellular matrix changes, performed transcriptomic cell-type enrichment analysis, measured cytokine expression, and quantified immune cell populations. DES-exposed mammary glands exhibited pronounced stromal remodeling, including increased collagen deposition and orientation by adulthood. Gene expression profiling indicated DES-induced stage-specific immune alterations: immune cell signatures were enriched at PND21 and PND90 but diminished at PND46. Correspondingly, DES increased macrophage populations at PND21 while reducing T-lymphocyte numbers at PND46 and PND90. DES exposure also dysregulated inflammatory cytokine/chemokine expression in adult glands, suggesting a persistent inflammatory environment. In conclusion, in utero exposure to an estrogenic compound can reprogram mammary development, inducing long-term changes in the extracellular matrix and immune landscape. These disruptions to stromal-immune homeostasis may impair normal mammary morphogenesis and increase susceptibility to breast pathologies later in life.

pharmacology and toxicology↗

bioRxiv2025

Gap junction communication regulates luminal-myoepithelial crosstalk and cell differentiation in a bi-layered human mammary epithelial cell model

Interactions between luminal and myoepithelial cells are essential for proper mammary gland development and function. However, only a few in vitro models allow the study of these interactions and their modulation by extrinsic factors. We developed a layered co-culture system (LCS) that mimics the bilayered architecture of the human breast epithelium, enabling direct contact and bidirectional crosstalk between luminal (MCF-12A) and myoepithelial (MYO1089) cells. We confirmed the formation of adherens and functional gap junctions across the layers. Transcriptomic analysis revealed that co-culture altered gene expression in pathways related to extracellular matrix remodeling, mRNA processing, response to external stimuli, hormonal signaling, receptor activity, and cell cycle regulation. In the LCS, MCF-12A cells exhibited a more luminal-like phenotype, with increased keratin-18 and decreased keratin-14, -smooth muscle actin (-SMA), and caldesmon-1 expression compared to 2D monoculture. Conversely, MYO1089 cells showed enhanced expression of myoepithelial markers, including -SMA, keratin-14, and caldesmon-1. Inhibition of gap junction communication by carbenoxolone disrupted these lineage-specific differentiation patterns. These findings highlight the importance of direct communication in regulating epithelial identity and underscore the LCS as a physiologically relevant model for studying mammary gland biology and external influences that can impact the epithelial differentiation. HighlightsA novel bilayered human co-culture system mimics the luminal and myoepithelial architecture of the mammary epithelium Direct luminal-myoepithelial contact enables formation of functional adherens and gap junctions Direct communication via gap junctions is essential for lineage-specific epithelial differentiation Co-culture induces transcriptional shifts related to proliferation, ECM regulation, and hormone response

cell biology↗

bioRxiv2025

Computationally designed stem-epitope mimetics elicit broadly reactive antibodies

Broad protection against diverse influenza viruses can be conferred by broadly neutralizing antibodies (bnAbs) targeting a conserved site on the hemagglutinin (HA) stem domain. However, the low immunogenicity of this antigenic region hinders the robust induction of such antibodies. Here, we showcase a structure-based immunogen design strategy focusing on the surface mimicry of antigenic sites. By leveraging the structural definition of a stem epitope, we apply computational protein design to develop epitope mimetics to focus the immune response against this site of viral vulnerability. The structurally complex antigenic site is displayed on heterologous protein scaffolds, retaining excellent binding towards known HA stem-specific bnAbs. Our epitope-mimetic induces stem-specific antibodies against highly divergent group 1 and 2 subtypes. The results provide a general framework for the design of novel immunogens eliciting focused immune responses which may be a valuable tool in the development of effective vaccine candidates against other variable pathogens.

biochemistry↗

bioRxiv2025

Impaired Myelination in Multiple Sclerosis Organoids: p21 Links Oligodendrocyte Dysfunction to Disease Subtype

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system. The cause of the disease is unknown but both genetic and environmental factors are strongly implicated in its pathogenesis. We derived cerebral and spinal cord organoids from induced pluripotent stem cells (iPSC) from healthy controls as well as from primary progressive MS (PPMS), secondary progressive MS (SPMS) and relapsing-remitting MS (RRMS) patients to investigate and compare oligodendrocyte differentiation and myelination capacity in healthy subjects and MS subtypes. In MS organoids, particularly in PPMS, we observed a decrease in p21 expression associated with a dysregulation of PAK1 and E2F1 expression. In parallel, a decrease in oligodendrocyte maturation was detected in long-term cultured cerebral and spinal cord organoids, especially in PPMS, leading to a reduced myelination capacity. Disruption of astrocyte and neuronal populations was also observed. Our findings demonstrate that in MS, inherent deficits in the p21 pathway may alter glial and neuronal cell populations and may contribute to the disease pathogenesis by reducing the capacity for myelin repair. Summary StatementUsing cerebral and spinal cord organoids derived from multiple sclerosis patients, we found an innate disruption of oligodendrocyte differentiation and myelination capacity as well as excitotoxicity, associated with PAK1 and E2F1-induced p21 dysregulation.

neuroscience↗

bioRxiv2022

Application of B cell immortalization for the isolation of antibodies and B cell clones from vaccine and infection settings

The isolation and characterization of neutralizing antibodies from infection and vaccine settings will inform future vaccine design, and methodologies that streamline the isolation of antibodies and the generation of B cell clones are of great interest. Retroviral transduction to express Bcl-6 and Bcl-xL in primary B cells has been shown to promote long-term B cell survival and antibody secretion in vitro, and can be used to isolate antibodies from memory B cells. The application of this methodology to B cell subsets from tissues and to B cells from individuals with chronic infection has not been extensively characterized. Here, we characterize Bcl-6/Bcl-xL B cell immortalization across multiple tissue types and B cell subsets in healthy and HIV-1 infected individuals, as well as individuals recovering from malaria. In HIV-1- and malaria-uninfected donors, naive and memory B cell subsets from PBMC and tonsil tissue transformed with similar efficiencies, and displayed similar characteristics after transformation with respect to their longevity and immunoglobulin secretion. In HIV-1-viremic individuals or in individuals after malaria infection, the CD27-CD21- memory B cell subsets transformed with lower efficiencies compared to the CD27+CD21+ populations, but following transformation B cells expanded and secreted IgG with similar efficiency. Using B cells from HIV-1-infected individuals, we combined Bcl-6/Bcl-xL B cell immortalization with a HIV-1 microneutralization assay to isolate broadly neutralizing antibodies related to VRC13 and VRC38.01. Overall, Bcl-6/Bcl-xL B cell immortalization can be used to isolate antibodies and generate B cell clones from multiple different B cell populations, albeit with different efficiencies.

immunology↗

bioRxiv2021

Durability of mRNA-1273-induced antibodies against SARS-CoV-2 variants

SARS-CoV-2 mutations may diminish vaccine-induced protective immune responses, and the durability of such responses has not been previously reported. Here, we present a comprehensive assessment of the impact of variants B.1.1.7, B.1.351, P.1, B.1.429, and B.1.526 on binding, neutralizing, and ACE2-blocking antibodies elicited by the vaccine mRNA-1273 over seven months. Cross-reactive neutralizing responses were rare after a single dose of mRNA-1273. At the peak of response to the second dose, all subjects had robust responses to all variants. Binding and functional antibodies against variants persisted in most subjects, albeit at low levels, for 6 months after the primary series of mRNA-1273. Across all assays, B.1.351 had the greatest impact on antibody recognition, and B.1.1.7 the least. These data complement ongoing studies of clinical protection to inform the potential need for additional boost vaccinations. One-Sentence SummaryMost mRNA-1273 vaccinated individuals maintained binding and functional antibodies against SARS-CoV-2 variants for 6 months.

immunology↗

bioRxiv2019

TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments

Solid state NMR is a powerful tool to probe membrane protein structure and motions in native lipid structures. Sample heating, caused by magic angle spinning and radio frequency irradiation in solid state NMR, produces uncertainties in sample temperature and thermal broadening caused by temperature distributions, which can also lead to sample deterioration. To measure the sample temperature in real time, and to quantify thermal gradients and their dependence on radio frequency irradiation or spinning frequency, we use the chemical shift thermometer TmDOTP, a lanthanide complex. Compared to other NMR thermometers (e.g., the proton NMR signal of water), the proton spectrum of TmDOTP exhibits higher thermal sensitivity and resolution. In addition, the H6 proton in TmDOTP has a large chemical shift (-175 ppm at 275 K) and is well resolved from the rest of the proton spectrum. We identified two populations of TmDOTP, with differing temperatures and dependency on the radio frequency irradiation power, within proteoliposome samples. We interpret these populations as arising from the supernatant and the pellet, which is sedimented from the sample spinning. Our results indicate that TmDOTP is an excellent internal standard for monitoring temperatures of biophysically relevant samples without distorting their properties.

biophysics↗