Biology subjects

Rosin, M.

Publications and source records attributed to Rosin, M..

11 recordsLinked to original sources

bioRxiv2026

Live-cell imaging of fetal microglia reveals time-dependent sex differences in their responsiveness to prenatal maternal stress

Prenatal maternal stress is increasingly being linked to neurodevelopmental disorders (NDDs), and across diverse maternal stressors, immune dysregulation is emerging as a common feature. This suggests that fetal microglia may influence neurodevelopment by detecting changes in signaling from the intrauterine environment. Using a mouse model of prenatal maternal stress, where pregnant mice were exposed to cold from embryonic day 11.5 (E11.5) to E15.5, we previously demonstrated that fetal microglia show region-specific and morphology-dependent sex differences in their responsiveness to prenatal maternal stress using static analyses. Here, we extend these analyses by conducting live-cell imaging on the E15.5 hypothalamic paraventricular nucleus (PVN) to assess microglial morphology, motility, and phagocytic behavior in real-time under homeostatic conditions and in response to prenatal maternal cold stress exposure. Prenatal maternal cold stress induced sex- and time-specific changes in microglial morphology in the PVN, where female microglia showed increased branch complexity across the entire live-cell video recording, while male microglia only showed this response at early time-points. Interestingly, PVN microglia also showed baseline sex differences in phagocytic behavior, with male microglia showing higher phagocytic activity as compared to female microglia. In response to prenatal maternal cold stress, male microglia showed a decrease in completed phagocytic events in the PVN, whereas female microglia showed increased engagement in phagocytic activity with no change in completed phagocytic events. Microglial motility was also altered in the PVN of female embryos at early time-points in response to prenatal maternal cold stress, but no such changes were observed in males. Together, these data demonstrate that fetal microglia show sex differences in key physiologies both at baseline and in response to prenatal maternal cold stress. Through time-resolved assessment of microglial dynamics, our findings also suggest that microglial responsiveness to prenatal maternal cold stress differs between males and females, which may help to provide a cellular basis for sex differences observed across many NDDs.

neuroscience↗

bioRxiv2026

Fetal microglia show region-specific and morphology-dependent sex differences in their responsiveness to prenatal maternal stress

The prevalence of neurodevelopmental disorders (NDDs) has increased dramatically, with growing evidence linking prenatal maternal stress exposure to NDDs. Across diverse maternal stressors, immune dysregulation emerges as a common feature, suggesting that fetal microglia may detect changes in the intrauterine environment and influence neurodevelopment. Accordingly, we utilized a mouse model of prenatal maternal cold stress to investigate the impact of maternal stress during pregnancy on fetal microglia morphology, cellular interactions, and phagocytic behaviors. Pregnant mice were exposed to cold stress from embryonic day 11.5 (E11.5) to E15.5 and fetal hypothalamic tissue was assessed from both male and female embryos. By adapting the morphology analysis toolset MicrogliaMorphology to assess fetal microglia, we demonstrate regional differences in microglial morphology in the fetal hypothalamus at baseline, with hypothalamic nuclei such as the paraventricular nucleus (PVN) containing fewer rod-like microglia compared to the broader hypothalamus. Interestingly, prenatal maternal cold stress induced a male-specific shift in microglial morphology from ameboid to ramified within the E15.5 PVN. Male embryos also displayed increased microglial-arginine vasopressin (AVP) neuronal interactions and microglial phagocytosis within the E15.5 PVN, but these changes were unique to microglia with a ramified morphology and were not observed when microglia with an ameboid or rod-like morphology were assessed. Using pHrodo bioparticles and flow cytometry, we further illustrate that prenatal maternal cold stress drives increased phagocytic activity in the E15.5 hypothalamus of male embryos, but not females. Together, these data demonstrate that prenatal maternal cold stress alters microglia morphology and drives morphology-dependent microglial interactions and phagocytic behaviors in male embryos which are unique to the hypothalamic PVN--a nuclei critical for social behaviors. Our findings also suggest that specific hypothalamic nuclei such as the PVN may be more sensitive to prenatal maternal stress, which has the potential to provide a cellular basis underlying the sex differences in microglia-dependent social deficits that were previously reported for this model.

neuroscience↗

bioRxiv2026

Prenatal exposure to maternal stress drives sex-specific neurodevelopmental disruptions in the fetal hypothalamus

The hypothalamus plays a central role in integrating physiological stressors to maintain homeostasis, yet how fetal neurodevelopment in the hypothalamus is shaped by intrauterine maternal stress exposure remains understudied. This is especially true in the context of sex-divergent mechanisms underlying neurodevelopmental disorders (NDDs), which are increasingly being linked to perturbation of the intrauterine environment. Herein, we utilize a mouse model of prenatal maternal cold stress exposure to study the impacts on neural stem and progenitor cell (NSPC) developmental programs in the fetal hypothalamus. Pregnant mice were exposed to cold stress from embryonic day 11.5 (E11.5) to E15.5 and fetal hypothalamic NSPCs from both male and female embryos were analyzed. Exposure to maternal stress altered fetal hypothalamic neurodevelopment, increasing TUJ1+ neuron number in males, while enhancing neuronal dendritic arborization in females. To define underlying molecular changes, we performed single-cell RNA sequencing of hypothalamic NSPCs. Interestingly, we identified distinct baseline transcriptional profiles between male and female NSPCs. In females, maternal stress upregulated pathways related to GABAergic differentiation and neuronal projection morphogenesis, with these alterations being maintained across more differentiated neuronal populations. Ligand-receptor analysis further indicated that maternal stress alters cell-cell communication within NSPCs, predominantly in females. Together, these findings demonstrate that prenatal maternal stress alters hypothalamic NSPC developmental programs uniquely in each sex, and suggest that disrupted intercellular signaling may contribute to underlying sex differences in social behaviors previously reported for this model (Rosin et al., 2021).

developmental biology↗

bioRxiv2026

The lipid raft marker flotillin FloA drives relocalization of the plasma membrane H+-ATPase PmaA as a protective response to calcium stress

Biological membranes are laterally heterogeneous and contain specialized microdomains called lipid rafts. Lipid rafts serve as organizational platforms that cluster signaling molecules or modulate membrane protein conformation through their unique lipid environment. There are specific lipid raft marker proteins whose functions remain obscure. One of these proteins is flotillin which has been linked to endocytosis. Here, we investigated the regulation and function of FloA, the sole flotillin homolog in the model fungus Aspergillus nidulans. FloA expression is specifically upregulated in response to calcium stress, which is a regulatory pattern also conserved in Aspergillus fumigatus. Whereas in A. fumigatus floA is regulated by the calcium regulatory protein CrzA, this is not the case in A. nidulans. BioID proximity labeling revealed that A. nidulans FloA physically interacts with proteins in the endocytic pathway as well as another lipid raft marker, the plasma membrane H+-ATPase PmaA. Under calcium stress, PmaA undergoes internalization from the cytoplasmic membrane. However, when floA is deleted, PmaA internalization is prevented, resulting in cell death. Together, we demonstrate that FloA is essential for the internalization of PmaA during calcium stress, a process that prevents intracellular calcium overload and promotes cell viability. Our results also provide further evidence for flotillin-assisted endocytosis. Author abstractLipids and proteins in a cell membrane can cluster together in small regions often called "lipid rafts", which help the cell interact with its surroundings. Lipid rafts can bring receptors together or influence how membrane proteins behave. Flotillin is a protein which is often found within lipid rafts, but its exact role is not well understood. Instead of using complex mammalian systems, we studied flotillins in the fungus Aspergillus nidulans, which is a simpler model organism that allows for a better understanding of cellular processes. We found that more flotillins are produced when the fungus is exposed to calcium stress. When flotillins were missing, the cells were unable to remove the protein PmaA from the cell membrane during calcium stress. As a result, the fungus could not cope with the calcium stress and eventually died. Therefore, we propose that flotillins are important for the fungus to reorganize its membranes and coping with calcium stress.

microbiology↗

bioRxiv2025

Gestational inhibition of CSF1R signaling using PLX5622 drives musculoskeletal changes in postnatal offspring

Despite our understanding of the musculoskeletal system under homeostatic conditions and during tissue remodeling, the interplay between muscle and bone development in response to gestational perturbations is less well understood. Here, we used the colony-stimulating factor-1 receptor (CSF1R) inhibitor PLX5622 to disrupt macrophage and osteoclast proliferation, differentiation, and survival during the embryonic period in order to study the impacts on craniofacial development using high-resolution microcomputed tomography (CT). Cranioskeletal and mandibular size and shape were assessed using geometric morphometric (GM) analysis and dense correspondence analysis (DeCA), while contrast-enhanced CT and DeCA were utilized to examine the consequences of prenatal CSF1R inhibition on P1 offspring musculature. Combined, we observed significant disruptions to cranioskeletal and mandibular morphologies, and notable changes in the shape of the muscles of mastication and tongue in newly born pups exposed to the CSF1R inhibitor PLX5622 in utero. By assessing the craniofacial skeleton and associated musculature at birth, we provide a more direct view of how inhibition of CSF1R signaling across embryogenesis contributes to changes in musculoskeletal development during periods of craniofacial morphogenesis.

developmental biology↗

bioRxiv2025

CSF1R+ macrophage and osteoclast depletion impairs neural crest proliferation and craniofacial morphogenesis

Despite a wealth of knowledge on the mechanisms underlying craniofacial morphogenesis during gestation, the roles of fetal macrophages and osteoclasts during this process remain less well characterized. Here, we used the pharmacological inhibitor PLX5622 to disrupt colony stimulating factor-1 receptor (CSF1R) signaling, which is essential for macrophage and osteoclast proliferation, differentiation, and survival. Prenatal PLX5622 exposure resulted in [~]50% depletion of CSF1R+ macrophages, with complete loss of osteoclasts. While there were no notable changes in craniofacial nerve or muscle development, prenatal exposure to PLX5622 resulted in skull doming and cranial suture impairments, in addition to disruptions to development of the premaxilla, mandible, ear ossicles, palate, and cranial base. In response to PLX5622 exposure, cytokine and chemokine signaling was altered and neural crest proliferation was impaired. Our data also highlight sex- and strain-specific differences in PLX5622 phenotypes and together demonstrate that CSF1R+ macrophages and osteoclasts are essential for craniofacial morphogenesis.

developmental biology↗

bioRxiv2023

Bacteria-induced activation of a fungal silent gene cluster is controlled by histone deacetylase Sirtuin E

Filamentous fungi encode an untapped reservoir of natural products whose biosynthesis enzymes are often encoded by gene clusters. The majority of these gene clusters are only activated under distinct environmental conditions such as the presence of distinct neighbouring microorganisms but not under standard laboratory conditions. Previously, we provided evidence for such a scenario with the specific activation of the silent ors gene cluster in the filamentous fungus Aspergillus nidulans by the bacterium Streptomyces rapamycinicus. The bacterium triggered the activation of the GcnE histone acetyltransferase that acetylated histone 3 in nucleosomes of the ors gene cluster and the basR transcription factor, and thereby the gene cluster. The inducing compound was shown to be the bacterial arginoketide azalomycin F. Here, by inhibitor studies with the pan-sirtuin inhibitor nicotinamide (NAM) the involvement of a sirtuin HDAC was implied. Accordingly, deletion of all six putative sirtuin-encoding genes (sirA-E and hstA) revealed that only deletion of sirE led to production of orsellinic acid by A. nidulans without the need of the bacterium. Also other effects on growth and colony morphology due to NAM were phenocopied by the sirE deletion mutant. Addition of NAM did not compensate for the loss of the BasR transcription factor required for activation of the ors gene cluster. Collectively, SirE is the negative regulator of the bacteria-induced activation of the ors BGC. In line, addition of NAM to monocultures of Aspergillus mulundensis encoding a sirtuin E with highest similarity to the A. nidulans protein also activated the ors BGC in this fungus.

microbiology↗

bioRxiv2022

Ubiquitous bacterial polyketides induce cross-kingdom microbial interactions

Although the interaction of prokaryotic and eukaryotic microorganisms is critical for the functioning of ecosystems, knowledge of the processes driving microbial interactions within communities is in its infancy. We previously reported that the soil bacterium Streptomyces iranensis specifically triggers the production of natural products in the fungus Aspergillus nidulans. Here, we discovered that arginine-derived polyketides serve as the bacterial signals for this induction. Arginine-derived polyketide-producing bacteria occur world wide. These producer bacteria and the fungi that decode and respond to this signal can be co-isolated from the same soil sample. Arginine-derived polyketides impact surrounding microorganisms both directly as well as indirectly, by inducing the production of natural products in fungi that further influence the composition of microbial consortia. One-Sentence SummaryUbiquitous bacterial polyketides are universal components of the chemical network for microbial communication

microbiology↗

bioRxiv2022

PD1+ T-cells correlate with Nerve Fiber Density as a prognostic biomarker in patients with resected perihilar cholangiocarcinoma.

Background & AimsPerihilar cholangiocarcinoma (pCCA) is a rare hepatobiliary malignancy. Nerve fiber invasion (NFI) shows cancer invading the nerve and is considered an aggressive feature. Nerve fiber density (NFD) consists of small nerve fibers without cancer invasion and is divided into high NFD (high numbers of small nerve fibers) or low NFD (low numbers of small nerve fibers). We aim to explore differences in immune cell populations and survival. MethodsWe applied multiplex immunofluorescence (mIF) on 47 pCCA surgically resected patients and investigated the immune cell composition in the tumor microenvironment (TME) of different nerve fiber phenotypes (NFI, high and low NFD). Extensive group comparison was carried out and the association with overall survival (OS) was assessed. ResultsThe NFI ROI was measured with highest CD68+ macrophage levels among 3 ROIs (NFI compared to tumor free p= 0.016 and to tumor p=0.034). Further, for NFI patients the density of co-inhibitory markers CD8+PD1+ and CD68+PD1+ were more abundant in the tumor rather than NFI ROI (p= 0.004 and p= 0.0029 respectively). Comparison between patients with NFD and NFI groups, the signals of co-expression of CD8+PD1+ as well as CD68+PD1+ were significantly higher in the high NFD group (p= 0.027 and p= 0.044, respectively). The OS for high NFD patients was 92 months median OS (95% CI:41-142), for low NFD patients 20 months ((95% CI: 4-36) and for NFI group of patients 19 months (95% CI 7-33). The OS for high NFD patients was significantly better compared to low NFD (p= 0.046) and NFI (p= 0.032). ConclusionsPD1+ T-cells correlate with high NFD as a prognostic biomarker, the biological pathway behind this needs to be investigated. Lay summaryNerve fibers play a dual role in the tumor microenvironment in pCCA. In our previous study, we showed that the presence of high numbers of small nerve fibers is associated with a better overall survival. In addition, we found that in high NFD patients PD1+ T-cells are significantly overexpressed. Therefore, we present high NFD as a promising prognostic biomarker. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=128 SRC="FIGDIR/small/475344v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@e30fadorg.highwire.dtl.DTLVardef@11a4e4aorg.highwire.dtl.DTLVardef@a04d8org.highwire.dtl.DTLVardef@1c425db_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2020

Heat Shock Protein 27 versus Estrogen Therapy for Post-Menopausal Atherosclerosis: Rethinking Mechanisms of Cholesterol Lowering

Aims The estrogen-inducible protein Heat Shock Protein 27 (HSP27) as well as anti-HSP27 antibodies are elevated in healthy subjects compared to cardiovascular disease patients. Vaccination of ApoE-/- mice with recombinant HSP25 (rHSP25, the murine ortholog), boosts anti-HSP25 levels and attenuates atherogenesis. As estrogens promote HSP27 synthesis, cellular release and blood levels, we hypothesize that menopause will result in loss of HSP27 atheroprotection. Hence, we now compare the efficacy of rHSP25 vaccination vs. estradiol (E2) therapy for the prevention of post-menopausal atherogenesis.Methods and Results ApoE-/- mice subjected to ovariectomy (OVX) showed a 65% increase atherosclerotic burden compared to sham mice after 5 weeks of a high fat diet. Relative to vaccination with rC1, a truncated HSP27 control peptide, atherogenesis was reduced by 5-weekly rHSP25 vaccinations (−43%), a subcutaneous E2 slow release pellet (−52%) or a combination thereof (−82%). Plasma cholesterol levels declined in parallel with the reductions in atherogenesis, but relative to rC1/OVX mice plasma PCSK9 levels were 52% higher in E2/OVX and 41% lower in rHSP25/OVX mice (p<0.0001 for both). Hepatic LDLR mRNA levels did not change with E2 treatment but increased markedly with rHSP25 vaccination. Conversely, hepatic PCSK9 mRNA increased 148% with E2 treatment vs. rC1/OVX but did not change with rHSP25 vaccination. In human HepG2 hepatocytes E2 increased PCSK9 promoter activity 303%, while the combination of [rHSP27 + PAb] decreased PCSK9 promoter activity by 64%.Conclusion The reduction in post-OVX atherogenesis and cholesterol levels with rHSP25 vaccination is associated with increased LDLR but not PCSK9 expression. Surprisingly, E2 therapy attenuates atherogenesis and cholesterol levels post-OVX without altering LDLR but increases PCSK9 expression and promoter activity. This is the first documentation of increased PCSK9 expression with E2 therapy and raises questions about balancing physiological estrogenic / PCSK9 homeostasis and targeting PCSK9 in women – are there effects beyond cholesterol?Competing Interest StatementEOB and YXC are inventors on US patents 8343915B2 and 8343916B2; EOB, CS and YXC are inventors on US patent application PCT/CA2016/051018; EOB is the inventor on US patent application 63/031,6402020; all intellectual property pertains to HSP27 diagnostics / therapeutics. EOB is the Scientific Co-Founder of Pemi31 Therapeutics Inc., a startup company that controls the aforementioned intellectual property. EOB, CS and YXC have equity interests in Pemi31 Therapeutics Inc.AbbreviationsAAbanti-HSP27 (or anti-HSP25) antibodiesApoE-/-apolipoprotein E nulla.u.absorbance unitsE217β estradiolHFDhigh fat dietHPRThypoxanthine-phosphoribosyltransferaseHSP27Heat Shock Protein 27HSP27o/eHSP27 over-expressingLDL-Clow density lipoprotein cholesterolLDLRlow density lipoprotein receptorMPmenopausemRNAmessenger RNANF-κBnuclear factor kappa light chain enhancer of activated B cellsONovernightOVXovariectomyPAbpolyclonal anti-HSP27 IgG antibodyPBSphosphate buffered salinePCSK9Proprotein Convertase Subtilisin/Kexin type 9rC1recombinant C-terminal truncation of HSP27 spanning amino acids 90-205rHSP27recombinant HSP27SDS-PAGEsodium dodecyl sulfate and polyacrylamide gelWBWestern BlotView Full Text

pathology↗

bioRxiv2020

Heat Shock Protein 27 Immune Complex Upregulates LDLR Expression Thereby Reducing Plasma Cholesterol and Atherogenesis

Elevated Heat Shock Protein 27 levels predict relative freedom from cardiovascular events. In ApoE-/- mice HSP27 over-expression or twice daily subcutaneous injections reduce blood and plaque cholesterol levels, inflammation and atherogenesis. While natural antibodies to HSP27 are present in human blood their role is unknown. Here, we show that blood levels of both HSP27 and anti-HSP27 IgG antibodies are elevated in healthy controls compared to patients with cardiovascular disease. ApoE-/- mice vaccinated with recombinant HSP25 (murine ortholog) develop elevated anti-HSP25 IgG antibodies and reduced levels of cholesterol, inflammation and atherosclerosis. The effects on cholesterol metabolism were divergent: increased hepatic LDLR expression and reduced plasma PCSK9 levels. In vitro, a polyclonal anti-HSP27 IgG antibody combined with rHSP27 to upregulate hepatocyte LDLR expression via an NF-kB-dependent pathway that is independent of SREBP2 expression and intracellular cholesterol levels. HSP27 immunotherapy represents a novel means of lowering not only cholesterol but also PCSK9.Competing Interest StatementEOB and YXC are inventors on US patents 8343915B2 and 8343916B2 and EOB, CS and YXC are inventors on US patent application PCT/CA2016/051018, all pertaining to HSP27 diagnostics / therapeutics. EOB is the Scientific Co-Founder of Pemi31 Therapeutics Inc., a startup company that controls the aforementioned intellectual property. EOB, CS and YXC have equity interests in Pemi31 Therapeutics Inc.View Full Text

pathology↗