Biology subjects

Anderson, R. M.

Publications and source records attributed to Anderson, R. M..

At least 19 recordsLinked to original sources

bioRxiv2026

Caloric restriction drives age-dependent and integrated remodeling of RNA processing and lipid composition in mouse brain

Caloric restriction (CR) extends lifespan and delays the onset of age-related diseases. Prior work has established numerous pathways that respond to CR, including growth signaling, metabolism, and inflammatory pathways. However, the molecular mechanisms that connect these pathways to enhanced lifespan and reduced disease risk remain unclear. Here, we demonstrate that RNA processing is altered in brains from mice on CR across adulthood and is linked to changes in lipid composition. Differential gene expression changes at each time point share a high degree of identity and functional overlap, with pathway enrichment including expected changes in metabolic pathways and neurotransmission related pathways. Differential splicing events were observed across adulthood; however, in contrast to the stable transcriptional program, RNA processing changes were dynamic and largely unique to each age group, suggesting regulatory mechanisms that were context specific. CR-induced changes in cortical lipid abundance profiles were highly coordinated across age groups, including increased abundance for lipids with higher degrees of unsaturation. Integrative analysis identified associations between specific lipid classes and transcripts, as well as particular categories of alternative splicing events. These data show that alternative RNA processing is a key mechanism harnessed by CR and linked to lipid homeostasis, providing new insight into metabolic reprogramming in the CR brain.

molecular biology↗

bioRxiv2026

Acetyl-CoA availability regulates neuronal metabolism, growth, and synaptic activity

The metabolite acetyl-CoA plays a central role in cellular metabolic homeostasis. As part of the secretory pathway, acetyl-CoA is imported into the endoplasmic reticulum (ER) by a membrane-bound transporter AT-1 (SLC33A1). AT-1 has been linked to peripheral neuropathy (heterozygous mutations), developmental delay with premature death (homozygous mutations) and intellectual disability with progeria (duplication). These phenotypes can be reproduced in the mouse. Here, we show that AT-1 overexpression in primary neurons impacts diverse phenotypes related to neuronal function and plasticity. At the gene level, AT-1 induces brain aging signatures, and key differences in ribosomal and synaptic processes were identified in both the transcriptome and the proteome. Changes in mitochondria-associated pathways were reflected in an increase in expression of mitochondrial master regulator PGC-1 and its target genes. Functionally, marked differences in mitochondrial membrane potential, architecture, and respiration were detected. Tracing experiments indicated altered glucose utilization in glycogen storage and nucleotide production. Shifts in redox metabolism were linked to differences in levels of NAD-dependent SIRT1 and CtBP2, with consequences for acetylated lysine modification. Depletion of lipid stores was associated with greater plasticity in fuel substrate utilization and a major shift in cellular lipid composition. These broad-scale changes in metabolism were coincident with reduced expression of synaptic proteins and reduced activity among synaptic networks, indicating that neuronal electrophysiology and network communication are coordinated at least in part through neuronal acetyl-CoA metabolism.

cell biology↗

bioRxiv2025

The G Protein-Coupled Receptor GPR31 Promotes Pro-inflammatory Responses in Pancreatic Islets and Macrophages

In type 1 diabetes (T1D), the innate and adaptive immune systems attack and eventually destroy the insulin-secreting pancreatic {beta} cells. During this process, {beta} cells activate inflammatory signaling pathways that augment the dysfunction and destruction imposed by cellular autoimmunity. The 12-lipoxygenase (12-LOX) pathway produces the pro-inflammatory eicosanoid 12-HETE, which induces oxidative and endoplasmic reticulum stress and results in diminished insulin secretion and apoptosis. The G protein-coupled receptor GPR31 has been identified as a putative receptor for 12-HETE. In this study, we generated conventional GPR31 knockout (KO) mice on the C57BL/6J background. To interrogate the role of GPR31 in {beta} cells, we treated islets from wildtype and Gpr31b KO mice with pro-inflammatory cytokines and subjected the islets to RNA sequencing. Differentially expressed pathways in Gpr31b KO islets included those pertaining to inflammation and oxidative stress, consistent with functional studies that demonstrated reduced cytokine-induced oxidative stress in Gpr31b KO islets compared to wildtype controls. Bone marrow-derived macrophages from Gpr31b KO mice showed reduced macrophage migration and decreased inflammatory IFN- and IFN-{gamma} signaling by RNA sequencing. To mimic islet and macrophage inflammation as seen in T1D, wildtype and Gpr31b KO mice were treated with the diabetogenic toxin streptozotocin. Compared to wildtype, Gpr31b KO mice had improved glucose tolerance and preserved {beta}-cell mass. siRNA knockdown of Gpr31b in non-obese diabetic (NOD) mice reduced insulitis, macrophage infiltration, and oxidative stress. Collectively, these findings are consistent with previously published data using 12/15-LOX KO mice and suggest that GPR31 mediates the pro-inflammatory responses of 12-HETE in both {beta} cells and macrophages.

molecular biology↗

bioRxiv2025

Systems biology analysis of vasodynamics in mouse cerebral arterioles during resting state and functional hyperemia

Cerebral hemodynamics is tightly regulated by arteriolar vasodynamics. In this study, a systems biology approach was employed to investigate how the interplay between passive, myogenic, neurogenic, and astrocytic responses shapes arteriolar vasodynamics in small rodents. A model of neurovascular coupling is proposed in which neurons inhibit and dampen the myogenic response to promote vasodilation during activation, and facilitate the myogenic response to promote rapid vasoconstriction immediately post-activation. In this model, inhibition of the myogenic response is mediated by the hyperpolarization of smooth muscle and endothelial cells. Dampening and facilitation of the response are mediated by neuronal production of nitric oxide and release of neuropeptide Y, respectively. We also introduce a model for gliovascular coupling, in which astrocytes periodically inhibit the myogenic response upon detecting an increase in myogenic activity through interactions between their endfeet and arterioles. Our study revealed that in the resting state, the interplay between the delayed myogenic response and passive distension, acting as negative and positive feedbacks respectively, generates undamped oscillations in vessel diameter, known as vasomotion. In the active state, these oscillations are disrupted by the neurogenic and astrocytic responses. The biophysical model of arteriolar vasodynamics presented in this study lays the foundation for quantitative analysis of cerebral hemodynamics for cerebrovascular health diagnostics and hemodynamic neuroimaging. Author summaryCerebral hemodynamic imaging is widely used to investigate brain function in-vivo. These signals are primarily shaped by arteriolar vasodynamics, which result from a combination of physiological processes mediated by multiple interacting cell types. A biophysical model of this dynamics offers a valuable computational framework for achieving more accurate and quantitative interpretation of hemodynamic signals. In this study, I applied a computational biology approach to incorporate several well-established cellular signaling pathways into a unified model, which was used to investigate system-level arteriolar behavior and identify missing or less understood mechanisms involved in cerebral blood flow regulation. Our results show that arteriolar vasodynamics is not solely driven by neurogenic responses; astrocytic response and hemo-vascular interactions also play important roles in shaping the observed dynamics. The model also provided a means to explore how in-silico analysis of hemodynamic signals can reveal potential cellular-level impairments that manifest as system-level changes in cerebral hemodynamics. Incorporating our proposed biophysical model into cerebral hemodynamic analysis can improve the fidelity of hemodynamic imaging--enabling more accurate inference of regional neuronal and astrocytic activity from hemodynamic signals, and enhancing our ability to diagnose cerebrovascular pathologies.

neuroscience↗

bioRxiv2025

Caloric restriction reprograms adipose tissues in rhesus monkeys

Caloric restriction (CR) is a dietary intervention that delays the onset of age-related diseases and enhances survival in diverse organisms, and although changes in adipose tissues have been implicated in the beneficial effects of CR the molecular details are unknown. Here we show shared and depot-specific adaptations to life-long CR in subcutaneous and visceral adipose depots taken from advanced age male rhesus monkeys. Differential gene expression and pathway analysis identified key differences between the depots in metabolic, immune, and inflammatory pathways. In response to CR, RNA processing and proteostasis-related pathways were enriched in both depots but changes in metabolic, growth, and inflammatory pathways were depot-specific. Commonalities and differences that distinguish adipose depots are shared among monkeys and humans and the response to CR is highly conserved. These data reveal depot-specificity in adipose tissue adaptation that likely reflects differences in function and contribution to age-related disease vulnerability. In BriefRhesus monkey adipose tissues are highly responsive to long-term caloric restriction, although the response is depot-specific. Shared features include proteostasis and RNA processing pathways, whereas metabolic pathways, alterations in processes influenced by growth signaling, and changes in exon usage were depot-specific. The impact of CR on subcutaneous adipose tissue is highly conserved between monkeys and humans. HighlightsO_LIAt the transcript level, SAT and VAT taken from the same animals show modest specialization, primarily in metabolic and immune pathways. C_LIO_LIThe transcriptome of SAT is more responsive to CR than that of VAT, with depot-specific differences in metabolic adaptation and cell type composition. C_LIO_LIRNA processing pathways are engaged by CR and transcript isoforms are enriched in both depots, but differential exon usage is limited to SAT. C_LIO_LIAdipose reprogramming is linked to CR induced differences in body composition and systemic indices of health. C_LIO_LIThe impact of CR on subcutaneous adipose tissue is highly similar between monkeys and humans. C_LI

genomics↗

bioRxiv2025

Enrichment of helminth mitochondrial genomes from faecal samples using hybridisation capture

New approaches are urgently needed to enrich rare or low-abundant DNA in complex samples. Soil-transmitted helminths (STHs) inhabit heterogeneous environments, including the gastrointestinal tract of their host as adults and are excreted as eggs and larvae in faeces, complicating our understanding of their biology and the use of genetic tools for species monitoring and population tracking. We have developed a hybridisation capture approach to enrich mitochondrial genome sequences of two STH species, the roundworm Ascaris lumbricoides and whipworm Trichuris trichiura, from extracted DNA from faecal material and worm specimens. Employing [~]1000 targeted probes, we achieved >6,000 and >12,000 fold enrichment for A. lumbricoides and T. trichiura, respectively, relative to direct whole genome shotgun (WGS) sequencing. Sequencing coverage was highly concordant with probe targets and correlated with the number of eggs per gram (EPG) of parasites present, from which DNA from as few as 336 EPG for Ascaris and 48 EPG for Trichuris were efficiently captured and sufficient to provide effective mitochondrial genome data. Finally, allele frequencies were highly concordant between WGS and hybridisation capture, suggesting little genetic information is lost with additional sample processing required for enrichment. Our hybridisation capture design and approach enables sensitive and scalable STH mitochondrial genome sampling from faecal DNA extracts and paves the way for broader hybridisation capture-based genome-wide applications and molecular epidemiology studies of STHs.

genomics↗

bioRxiv2025

12-Lipoxygenase inhibition improves glucose homeostasis and obesity-associated inflammation in human gene replacement mice

Obesity-associated inflammation is characterized by macrophage infiltration into peripheral tissues, contributing to the progression of prediabetes and type 2 diabetes (T2D). The enzyme 12-lipoxygenase (12-LOX) catalyzes the formation of pro-inflammatory eicosanoids and is known to promote the migration of macrophages, yet its role in obesity-associated inflammation remains incompletely understood. Furthermore, differences between mouse and human orthologs of 12-LOX have limited efforts to study existing pharmacologic inhibitors of 12-LOX. In this study, we utilized a human gene replacement mouse model in which the gene encoding mouse 12-LOX (Alox15) is replaced by the human ALOX12 gene. As a model of obesity and dysglycemia, we administered these mice a high-fat diet. We subsequently investigated the effects of VLX-1005, a potent and selective small molecule inhibitor of human 12-LOX. Oral administration of VLX-1005 resulted in improved glucose homeostasis, decreased {beta} cell dedifferentiation, and reduced macrophage infiltration in islets and adipose tissue. Analysis of the stromal vascular fraction from adipose tissue showed a reduction in myeloid cells and cytokine expression with VLX-1005 treatment, indicating decreased adipose tissue inflammation. In a distinct mouse model in which Alox15 was selectively deleted in myeloid cells, we observed decreased {beta} cell dedifferentiation and reduced macrophage infiltration in both islets and adipose tissue, suggesting that the effects of VLX-1005 may relate to the inhibition of 12-LOX in macrophages. These findings highlight 12-LOX as a key factor in obesity-associated inflammation and suggest that 12-LOX inhibition could serve as a therapeutic strategy to improve glucose homeostasis and peripheral inflammation in the setting of obesity and T2D.

physiology↗

bioRxiv2024

Molecular epidemiology of Ascaris lumbricoides following multiple rounds of community-wide treatment: who infects whom?

Control and elimination of the parasite Ascaris lumbricoides relies on mass administration using a limited number of anti-helminthics. Whilst these programs have reduced the infection intensity and prevalence within many endemic regions transmission is poorly understood, with reinfection commonly occurring following cessation of treatment. Here, we utilise genomic data to understand parasite transmission within and between households in a community and the genomic impact of repeated MDA. We sequenced 54 whole-genomes from individuals in a longitudinal cohort epidemiological study of transmission and drug treatment extending over 6 years. We found that fine-scale population structure exists in spatially distinct clusters of infected individuals with reinfection occurring within or between geographically close households. This observation helps inform the policy of future control in low prevalence settings suggesting more targeted treatment of infection hotspots We found evidence of positive selection acting on members of gene families previously implicated in reduced drug efficacy but detect no high frequency of impactful variants. As efforts to eliminate A. lumbricoides intensify, our study provides a foundation for genomic surveillance to help identify both who infects whom and the impact of repeated drug treatment.

genomics↗

bioRxiv2024

The integrated stress response promotes macrophage inflammation and migration in autoimmune diabetes

Type 1 Diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin producing pancreatic {beta}-cells. Macrophages infiltrate islets early in T1D pathogenesis, preceding the influx of T- and B-lymphocytes. The integrated stress response (ISR), a cellular pathway activated during stress, coordinates adaptive changes in gene expression to maintain cell function and survival. To study the ISR in macrophages, bone-marrow derived macrophages were treated with a pharmacological inhibitor of the ISR (ISRIB) and polarized to a proinflammatory M1-like state. We found a reduction in the number of proinflammatory macrophages as well as a reduction in iNOS mRNA and protein levels with ISRIB treatment. RNA-sequencing revealed a reduction in pathways related to stress responses, including ER stress, reactive oxygen species (ROS) regulation, and autophagy as well as migration pathway genes. ISRIB treatment led to decreased macrophage migration after stimulation in vitro and decreased macrophages to the site of injury after tailfin cut in zebrafish in vivo. Pre-diabetic female non-obese diabetic (NOD) mice administered ISRIB demonstrated an overall reduction in the macrophage numbers in the pancreatic islets. Additionally, the insulitic area of pancreata from ISRIB treated NOD mice had increased PD-L1 levels. Our study provides new insights into ISR signaling in macrophages and demonstrates that the ISR might serve as a potential target for intervention in macrophages during early T1D pathogenesis.

immunology↗

bioRxiv2024

Hypusinated and unhypusinated isoforms of eIF5A exert distinct effects in models of pancreas development and function

Hypusination of eukaryotic translation initiation factor 5A (eIF5A) is essential for its role in translation elongation and termination. Although the function of hypusinated eIF5A (eIF5AHyp) in cellular proliferation is well-characterized, the role of its unhypusinated form (eIF5ALys) remains unclear. We hypothesized that eIF5ALys exerts independent effects on cellular replication and metabolism distinct from the loss of eIF5AHyp. To test this hypothesis, we utilized zebrafish and mouse models with inducible knockdowns of deoxyhypusine synthase (DHPS) and eIF5A to investigate their roles in cellular growth. Gene expression analysis via RNA sequencing and morphometric measurements of pancreas and {beta}-cell mass were performed to assess phenotypic changes and identify affected biological pathways. Loss of DHPS in zebrafish resulted in significant defects in pancreatic growth, accompanied by the dysregulation of mRNA translation, neurogenesis, and stress pathways. By contrast, knockdown of eIF5A had minimal impact on pancreas development, suggesting that the effects of DHPS loss are not solely due to the lack of eIF5AHyp. In mice, {beta} cell-specific deletion of DHPS impaired {beta} cell mass expansion and glucose tolerance, while eIF5A deletion had no statistically significant effects. These findings reveal an independent role for eIF5ALys in regulating developmental and functional responses and that a balance in levels of the hypusinated and unhypusinated isoforms of eIF5A may be pivotal in cellular phenotypes in health and disease.

cell biology↗

bioRxiv2024

Global diversity of soil-transmitted helminths reveals population-biased genetic variation that impacts diagnostic targets

Soil-transmitted helminths (STHs) are intestinal pathogens affecting over a billion people worldwide. STH control relies on microsopy-based diagnostics to monitor parasite prevalence and enable post-treatment surveillance, however, molecular diagnostics are rapidly being developed due to increased sensitivity, particularly in low-STH-prevalence settings. The genetic diversity of helminths and its potential impact on molecular diagnostics remains unclear. Using low-coverage genome sequencing, we assessed the presence of STHs in worm, faecal and purified egg samples from 27 countries, identifying differences in the genetic connectivity and diversity of STH-positive samples across regions and cryptic diversity between closely related human- and pig-infective species. We defined substancial copy number and sequence variants in current diagnostic targets and validated the impact of genetic variants on qPCR diagnostics using in vitro assays. Our study provides insights into the diversity and genomic epidemiology of STHs, highlighting challenges and opportunities for developing molecular diagnostics needed to support STH control efforts.

genomics↗

bioRxiv2024

Reversal of neuronal tau pathology, metabolic dysfunction, and electrophysiological defects via adiponectin pathway dependent AMPK activation.

Changes in brain mitochondrial metabolism are coincident with functional decline; however, direct links between the two have not been established. Here, we show that mitochondrial targeting via the adiponectin receptor activator AdipoRon (AR) clears neurofibrillary tangles (NFTs) and rescues neuronal tauopathy-associated defects. AR reduced levels of phospho-tau and lowered NFT burden by a mechanism involving the energy-sensing kinase AMPK and the growth-sensing kinase GSK3b. The transcriptional response to AR included broad metabolic and functional pathways. Induction of lysosomal pathways involved activation of LC3 and p62, and restoration of neuronal outgrowth required the stress-responsive kinase JNK. Negative consequences of NFTs on mitochondrial activity, ATP production, and lipid stores were corrected. Defects in electrophysiological measures (e.g., resting potential, resistance, spiking profiles) were also corrected. These findings reveal a network linking mitochondrial function, cellular maintenance processes, and electrical aspects of neuronal function that can be targeted via adiponectin receptor activation.

neuroscience↗

bioRxiv2023

Mitochondrial regulator PGC-1a in neuronal metabolism and brain aging

The brain is a high energy tissue, and the cell types of which it is comprised are distinct in function and in metabolic requirements. The transcriptional co-activator PGC-1a is a master regulator of mitochondrial function and is highly expressed in the brain; however, its cell-type specific role in regulating metabolism has not been well established. Here, we show that PGC-1a is responsive to aging and that expression of the neuron specific PGC-1a isoform allows for specialization in metabolic adaptation. Transcriptional profiles of the cortex from male mice show an impact of age on immune, inflammatory, and neuronal functional pathways and a highly integrated metabolic response that is associated with decreased expression of PGC-1a. Proteomic analysis confirms age-related changes in metabolism and further shows changes in ribosomal and RNA splicing pathways. We show that neurons express a specialized PGC-1a isoform that becomes active during differentiation from stem cells and is further induced during the maturation of isolated neurons. Neuronal but not astrocyte PGC-1a responds robustly to inhibition of the growth sensitive kinase GSK3b, where the brain specific promoter driven dominant isoform is repressed. The GSK3b inhibitor lithium broadly reprograms metabolism and growth signaling, including significantly lower expression of mitochondrial and ribosomal pathway genes and suppression of growth signaling, which are linked to changes in mitochondrial function and neuronal outgrowth. In vivo, lithium treatment significantly changes the expression of genes involved in cortical growth, endocrine, and circadian pathways. These data place the GSK3b/PGC-1a axis centrally in a growth and metabolism network that is directly relevant to brain aging.

cell biology↗

bioRxiv2023

Mass spectrometry-based multi-omics identifies metabolic signatures of sarcopenia in rhesus monkey skeletal muscle

Sarcopenia is a progressive disorder characterized by age-related loss of skeletal muscle mass and function. Although significant progress has been made over the years to identify the molecular determinants of sarcopenia, the precise mechanisms underlying the age-related loss of contractile function remains unclear. Advances in omics technologies, including mass spectrometry-based proteomic and metabolomic analyses, offer great opportunities to better understand sarcopenia. Herein, we performed mass spectrometry-based analyses of the vastus lateralis from young, middle-aged, and older rhesus monkeys to identify molecular signatures of sarcopenia. In our proteomic analysis, we identified numerous proteins that change with age, including those involved in adenosine triphosphate and adenosine monophosphate metabolism as well as fatty acid beta oxidation. In our untargeted metabolomic analysis, we identified multiple metabolites that changed with age largely related to energy metabolism including fatty acid beta oxidation. Pathway analysis of age-responsive proteins and metabolites revealed changes in muscle structure and contraction as well as lipid, carbohydrate, and purine metabolism. Together, this study discovers new metabolic signatures and offer new insights into the molecular mechanism underlying sarcopenia for the evaluation and monitoring of therapeutic treatment of sarcopenia. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=67 SRC="FIGDIR/small/551315v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1dc0addorg.highwire.dtl.DTLVardef@14d73b8org.highwire.dtl.DTLVardef@1e8733forg.highwire.dtl.DTLVardef@1e65408_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical Abstract

biochemistry↗

bioRxiv2022

Nonlinear microscale mechanics of actin networks governed by coupling of filament crosslinking and stabilization

Actin plays a vital role in maintaining the stability and rigidity of biological cells while allowing for cell motility and shape change. The semiflexible nature of actin filaments - along with the myriad actin-binding proteins (ABPs) that serve to crosslink, bundle, and stabilize filaments - are central to this multifunctionality. The effect of ABPs on the structural and mechanical properties of actin network mechanics has been the topic of fervent investigation over the past few decades, revealing diverse structures from isotropic percolated networks to heterogeneous bundles that depend on the crosslinker type and concentration. Yet, the impact of filament stabilization and stiffening via ABPs on the nonlinear response of crosslinked networks has yet to be explored. Here, we perform optical tweezers microheology measurements to characterize the nonlinear force response and relaxation dynamics of actin networks in the presence of varying concentrations of -actinin, which transiently crosslinks actin filaments, and phalloidin, which stabilizes filamentous actin and increases its persistence length. We show that crosslinking and stabilization can act both synergistically and antagonistically to tune the network resistance to nonlinear straining. For example, phalloidin-stabilization leads to enhanced elastic response and reduced dissipation at large strains and timescales, while the initial microscale force response is reduced compared to networks without phalloidin. Moreover, we find that stabilization switches this initial response from that of stress-stiffening to softening despite the increased filament stiffness that phalloidin confers. Finally, we show that both crosslinking and stabilization are necessary to elicit these emergent features, while the effect of stabilization on networks without crosslinkers is much more subdued. We suggest that these intriguing mechanical properties arise from the competition and cooperation between filament connectivity, bundling, and rigidification, shedding light on how ABPs with distinct roles can act in concert to mediate diverse mechanical properties of the cytoskeleton and bio-inspired polymeric materials.

biophysics↗

bioRxiv2022

Microscopic Imaging of Epigenetic Age

Biomarkers of biological age that predict the risk of disease and expected lifespan better than chronological age are key to efficient and cost-effective healthcare1-3. To advance a personalized approach to healthcare, such biomarkers must perform on the individual rather than population level, demonstrate single cell resolution, and provide scalable and cost-effective measurements. We developed a novel approach - image-based chromatin and epigenetic age (ImAge), that utilizes image texture features based on the patterns of chromatin and epigenetic marks in single nuclei. We observed the emergence of intrinsic trajectories of ImAge using dimensionality reduction without regression on chronological age. ImAge was correlated with chronological age in all tissues and organs examined and was consistent with the expected acceleration and/or deceleration of biological age in chronologically identical mice treated with chemotherapy or following a caloric restriction regimen, respectively. ImAge from chronologically identical mice inversely correlated with their locomotor activity (greater activity for younger ImAge), consistent with the essential role of locomotion as an aging biomarker. Finally, we demonstrated that ImAge is reduced upon partial reprogramming in vivo following transient expression of OSKM cassette in the liver and skeletal muscles of old mice and validated the power of ImAge to assess the heterogeneity of reprogramming. We propose that ImAge represents the first-in-class individual-level biomarker of aging and rejuvenation with single-cell resolution.

systems biology↗

bioRxiv2021

12-Lipoxygenase Governs the Innate Immune Pathogenesis of Islet Inflammation and Autoimmune Diabetes

Macrophages and related myeloid cells are innate immune cells that participate in the early islet inflammation of type 1 diabetes (T1D). The inflammatory signals and antigen presentation by these cells may be inducers of the adaptive immune response that is the hallmark of T1D. The enzyme 12-lipoxygenase (12-LOX) catalyzes the formation of pro-inflammatory eicosanoids from membrane-derived phospholipids, but its role and mechanisms in the pathogenesis of islet inflammation have not been elucidated. Leveraging a model of T1D-like islet inflammation in zebrafish, we show here that macrophages contribute significantly to the loss of {beta}-cells and the subsequent development of hyperglycemia. Depletion or inhibition of 12-LOX in this model resulted in significantly reduced macrophage infiltration into islets with preservation of {beta}-cell mass. In mice, we deleted the gene encoding 12-LOX (Alox15) in the myeloid lineage in the non-obese diabetic (NOD) model of T1D. Myeloid cell-specific Alox15 knockout NOD mice demonstrated reduced insulitis and T-cell responses, preserved {beta} cell mass, and almost complete protection from the development of T1D. A critical effect of 12-LOX depletion appeared secondary to a defect in myeloid cell migration, a function required for immune surveillance and tissue injury responses. This effect on migration appeared to be secondary to the loss of the chemokine receptor CXCR3. Transgenic expression of the gene encoding CXCR3 rescued the migrator defect in zebrafish 12-LOX morphants. Taken together, our results reveal a formative role for innate immune myeloid cells in the early pathogenesis of T1D and identify 12-LOX as a necessary enzyme to promote their pro-diabetogenic phenotype in the context of autoimmunity.

immunology↗

bioRxiv2020

Extensive hybridization between pig and human Ascaris identifies a highly interbred species complex infecting humans

Human ascariasis is a major neglected tropical disease caused by the nematode Ascaris lumbricoides. We report a 296 megabase (Mb) reference quality genome comprised of 17902 protein-coding genes derived from a single, representative Ascaris worm collected from 60 human hosts in Kenyan villages where pig husbandry is rare. Notably, the majority of human isolates (63/68) possessed mitochondrial genomes that clustered closer to the pig parasite Ascaris suum than to A. lumbricoides. Comparative phylogenomic analyses identified over 11 million nuclear-encoded SNPs but just two distinct genetic types that had recombined across the genomes analysed. The nuclear genomes had extensive heterozygosity and all samples existed as genetic mosaics with either A. suum-like or A. lumbricoides-like inheritance patterns supporting a highly interbred Ascaris species genetic complex. As no barriers appear to exist for anthroponotic transmission of these "hybrid" worms, a one-health approach to control the spread of human ascariasis will be necessary.

genomics↗