Development Of Organisms Research Articles

EHBP1 Is Critically Involved in the Dendritic Arbor Formation and Is Coupled to Factors Promoting Actin Filament Formation.

The coordinated action of a plethora of factors is required for the organization and dynamics of membranous structures critically underlying the development and function of cells, organs, and organisms. The evolutionary acquisition of additional amino acid motifs allows for expansion and/or specification of protein functions. We identify a thus far unrecognized motif specific for chordata EHBP1 proteins and demonstrate that this motif is critically required for interaction with syndapin I, an F-BAR domain-containing, membrane-shaping protein predominantly expressed in neurons. Gain-of-function and loss-of-function studies in rat primary hippocampal neurons (of mixed sexes) unraveled that EHBP1 has an important role in neuromorphogenesis. Surprisingly, our analyses uncovered that this newly identified function of EHBP1 did not require the domain responsible for Rab GTPase binding but was strictly dependent on EHBP1's syndapin I binding interface and on the presence of syndapin I in the developing neurons. These findings were underscored by temporally and spatially remarkable overlapping dynamics of EHBP1 and syndapin I at nascent dendritic branch sites. In addition, rescue experiments demonstrated the necessity of two additional EHBP1 domains for dendritic arborization, the C2 and CH domains. Importantly, the additionally uncovered critical involvement of the actin nucleator Cobl in EHBP1 functions suggested that not only static association with F-actin via EHBP1's CH domain is important for dendritic arbor formation but also actin nucleation. Syndapin interactions organize ternary protein complexes composed of EHBP1, syndapin I, and Cobl, and our functional data show that only together these factors give rise to proper cell shape during neuronal development.

DNA Barcoding Technology for Lineage Recording and Tracing to Resolve Cell Fate Determination.

In various biological contexts, cells receive signals and stimuli that prompt them to change their current state, leading to transitions into a future state. This change underlies the processes of development, tissue maintenance, immune response, and the pathogenesis of various diseases. Following the path of cells from their initial identity to their current state reveals how cells adapt to their surroundings and undergo transformations to attain adjusted cellular states. DNA-based molecular barcoding technology enables the documentation of a phylogenetic tree and the deterministic events of cell lineages, providing the mechanisms and timing of cell lineage commitment that can either promote homeostasis or lead to cellular dysregulation. This review comprehensively presents recently emerging molecular recording technologies that utilize CRISPR/Cas systems, base editing, recombination, and innate variable sequences in the genome. Detailing their underlying principles, applications, and constraints paves the way for the lineage tracing of every cell within complex biological systems, encompassing the hidden steps and intermediate states of organism development and disease progression.

Sequential deregulation of histone marks, chromatin accessibility and gene expression in response to PROTAC-induced degradation of ASH2L

The trithorax protein ASH2L is essential for organismal and tissue development. As a subunit of COMPASS/KMT2 complexes, ASH2L is necessary for methylation of histone H3 lysine 4 (H3K4). Mono- and tri-methylation at this site mark active enhancers and promoters, respectively, although the functional relevance of H3K4 methylation is only partially understood. ASH2L has a long half-life, which results in a slow decrease upon knockout. This has made it difficult to define direct consequences. To overcome this limitation, we employed a PROTAC system to rapidly degrade ASH2L and address direct effects. ASH2L loss resulted in inhibition of proliferation of mouse embryo fibroblasts. Shortly after ASH2L degradation H3K4me3 decreased with its half-life varying between promoters. Subsequently, H3K4me1 increased at promoters and decreased at some enhancers. H3K27ac and H3K27me3, histone marks closely linked to H3K4 methylation, were affected with considerable delay. In parallel, chromatin compaction increased at promoters. Of note, nascent gene transcription was not affected early but overall RNA expression was deregulated late after ASH2L loss. Together, these findings suggest that downstream effects are ordered but relatively slow, despite the rapid loss of ASH2L and inactivation of KMT2 complexes. It appears that the systems that control gene transcription are well buffered and strong effects are only beginning to unfold after considerable delay.

Effect of ZnO Nanoparticles During the Process of Phytoremediation of Soil Contaminated with As and Pb Cultivated with Sunflower (Helianthus annuus L.)

Urbanization and industrialization have caused the production of pollutants in the soil, water, and air systems, negatively influencing plants, animals, humans, and the ecosystem. Heavy metals, such as arsenic (As), lead (Pb), cobalt (Co), chromium (Cr), mercury (Hg), and nickel (Ni), affect the development of organisms. In this study, as a novel alternative, the performance of zinc oxide nanoparticles (ZnO NPs) in sunflower plant growth (Helianthus annuus L.) and the decontamination of soils with As and Pb was investigated. For this purpose, in natural soil contaminated with As (0.02 mg kg of dry soil) and Pb (0.2 mg/kg of dry soil), sunflower plants were allowed to grow in pots for 25, 35, and 45 days after emergence. Morphological parameters were measured for the plants. The stems, leaves, and roots were dried (80 °C), ground, and finally, mineral analysis was performed by plasma atomic emission spectrometry (ICP). ZnO NPs were applied to the soil at two concentrations (0.3 and 0.6 mg/kg) and the control. ZnO NPs application resulted in plant growth and root length 25 days after emergence (DAE). The interaction between ZnO NPs and metals significantly negatively affected the variable root length. The roots, stems, and leaves accumulated metals at 25 and 45 DAE. Bioconcentration (BCF) and translocation (TF) factors were higher in Zn at 45 DAE. The phytoextraction by H. annuus assisted with ZnO NPs helps remediate polluted soils, potentiating the plant's hyperaccumulation characteristics. The results of this experiment offer basic information on the interaction of ZnO NPs in the phytoremediation process of soil contaminated with heavy metals. However, it is crucial to know the potential of NPs in soils with higher concentrations of contaminants in the soil, which we consider one of the limitations of this work, using low concentrations of heavy metals. Therefore, more research is required to corroborate the effectiveness of ZnO NPs in soils contaminated with Pb and Zn during the phytoremediation process with sunflower plants.Graphical

Copper in Gynecological Diseases.

Copper (Cu) is an essential micronutrient for the correct development of eukaryotic organisms. This metal plays a key role in many cellular and physiological activities, including enzymatic activity, oxygen transport, and cell signaling. Although the redox activity of Cu is crucial for enzymatic reactions, this property also makes it potentially toxic when found at high levels. Due to this dual action of Cu, highly regulated mechanisms are necessary to prevent both the deficiency and the accumulation of this metal since its dyshomeostasis may favor the development of multiple diseases, such as Menkes' and Wilson's diseases, neurodegenerative diseases, diabetes mellitus, and cancer. As the relationship between Cu and cancer has been the most studied, we analyze how this metal can affect three fundamental processes for tumor progression: cell proliferation, angiogenesis, and metastasis. Gynecological diseases are characterized by high prevalence, morbidity, and mortality, depending on the case, and mainly include benign and malignant tumors. The cellular processes that promote their progression are affected by Cu, and the mechanisms that occur may be similar. We analyze the crosstalk between Cu deregulation and gynecological diseases, focusing on therapeutic strategies derived from this metal.

Effects of temperature on fertility in hybrid hermaphroditic Argopecten scallops

Temperature is a critical factor affecting the growth, development and reproduction of aquatic organisms. The interspecific F1 hybrids between hermaphroditic bay scallops (Argopecten irradians) and Peruvian scallops (Argopecten purpuratus) exhibited significant heterosis in yield, but sterility in most hybrids hindered large scale interspecific hybridization and speciation. We first explored the physiological effect of temperature on the fertility of hybrid hermaphroditic Argopecten scallops with F1 hybrids treated at 6 different temperatures (18 °C, 20 °C, 22 °C, 24 °C, 26 °C, and 28 °C). The results showed that the final mortality rates from 18 °C to 22 °C were significantly lower than those from 24 °C to 28 °C. With the decrease of the temperature, the size, gonadal index, ATP content, and expression of most genes related to fertility regulation gradually decreased in F1 hybrids treated at 22 °C, 20 °C and 18 °C, and the apoptosis rate of oocytes gradually increased, but the activity of SOD (superoxide dismutase) and CAT (catalase) first increased and then decreased. The fertility of hybrids treated at 22 °C, 20 °C and 18 °C gradually decreased with the decrease of the temperature. According to gene expression, temperature may regulate the fertility of Argopecten F1 hybrids by affecting apoptosis, meiosis, ATP production and damage repair to inhibit the genesis and maturation of germ cells. Our findings suggest that temperature can affect the hybrid fertility of hermaphroditic Argopecten scallops and provide the basis for further research on the mechanism of temperature on sterility.

GRD-1/PTR-11, the C. elegans hedgehog/patched-like morphogen-receptor pair, modulates developmental rate.

Both hedgehog (Hh) and target of rapamycin complex 2 (TORC2) are central, evolutionarily conserved signaling pathways that regulate development and metabolism. In C. elegans, loss of the essential TORC2 component RICTOR (rict-1) causes delayed development, shortened lifespan, reduced brood, small size and increased fat. Here, we report that knockdown of both the hedgehog-related morphogen grd-1 and its patched-related receptor ptr-11 rescues delayed development in TORC2 loss-of-function mutants, and grd-1 and ptr-11 overexpression delays wild-type development to a similar level to that in TORC2 loss-of-function animals. These findings potentially indicate an unexpected role for grd-1 and ptr-11 in slowing developmental rate downstream of a nutrient-sensing pathway. Furthermore, we implicate the chronic stress transcription factor pqm-1 as a key transcriptional effector in this slowing of whole-organism growth by grd-1 and ptr-11. We propose that TORC2, grd-1 and ptr-11 may act linearly or converge on pqm-1 to delay organismal development.

SingleScan: a comprehensive resource for single-cell sequencing data processing and mining

Single-cell sequencing has shed light on previously inaccessible biological questions from different fields of research, including organism development, immune function, and disease progression. The number of single-cell-based studies increased dramatically over the past decade. Several new methods and tools have been continuously developed, making it extremely tricky to navigate this research landscape and develop an up-to-date workflow to analyze single-cell sequencing data, particularly for researchers seeking to enter this field without computational experience. Moreover, choosing appropriate tools and optimal parameters to meet the demands of researchers represents a major challenge in processing single-cell sequencing data. However, a specific resource for easy access to detailed information on single-cell sequencing methods and data processing pipelines is still lacking. In the present study, an online resource called SingleScan was developed to curate all up-to-date single-cell transcriptome/genome analyzing tools and pipelines. All the available tools were categorized according to their main tasks, and several typical workflows for single-cell data analysis were summarized. In addition, spatial transcriptomics, which is a breakthrough molecular analysis method that enables researchers to measure all gene activity in tissue samples and map the site of activity, was included along with a portion of single-cell and spatial analysis solutions. For each processing step, the available tools and specific parameters used in published articles are provided and how these parameters affect the results is shown in the resource. All information used in the resource was manually extracted from related literature. An interactive website was designed for data retrieval, visualization, and download. By analyzing the included tools and literature, users can gain insights into the trends of single-cell studies and easily grasp the specific usage of a specific tool. SingleScan will facilitate the analysis of single-cell sequencing data and promote the development of new tools to meet the growing and diverse needs of the research community. The SingleScan database is publicly accessible via the website at http://cailab.labshare.cn/SingleScan.

Impact of Antimicrobial Stewardship on Reducing Antimicrobial Resistance.

Antimicrobial resistance has become a serious global issue, posing a significant threat to public health and healthcare professionals. Since the advent of penicillin, many antibiotics have lost their effectiveness in combating microbes simply due to inappropriate, irrational, unnecessary, and unrestricted use. The ineffectiveness of an increasing number of antibiotics necessitates the utilization of more potentantimicrobial agents for combatting uncomplicated infections. In response to the escalating prevalence of multidrug-resistant pathogens and the imperative to curtail the demand for novel antibiotics, the Antimicrobial Stewardship Program was conceived and implemented. This initiative is characterized by a lead physician, ideally possessing expertise in infectious diseases, alongside a pharmacist serving as a secondary leader and a microbiologist with defined responsibilities to achieve several objectives. These objectives include reducing indiscriminate usage of antimicrobial agents, promoting selective antimicrobial utilization based on culture results, de-escalating therapy from broad-spectrum to targeted antimicrobial agents, and transitioning from parenteral to oral administration when feasible. These objectives are pursued through a combination of pre-prescription and post-prescription strategies. While the Antimicrobial Stewardship Program is widely established in developed nations, a pressing need exists for its more comprehensive implementation in less developed regions.This review aims to examine the strategies used in antimicrobial stewardship programs to evaluate their effectiveness in preventing the development of multidrug-resistant organisms (MDROs) based on existing research studies.Under the Antimicrobial Stewardship Program, education of healthcare professionals and continuous disposal of information about antimicrobial resistance have helped to restrict the emergence of multidrug-resistant organisms.

Elevated lead (Pb) in urban European starling (Sturnus vulgaris) feathers is not correlated to physiology or behavior

Urbanization is rapidly changing the environment and creating new challenges in the lives of animals across the globe. Anthropogenic contaminants—like heavy metals—can persist within the environment for prolonged periods of time and present a widespread problem for those living near contaminated areas. Lead (Pb) was a commonly used heavy metal that continues to threaten the health of all organisms despite being phased out, especially in urban areas where historical use was more common. In this study, a common urban-adapter, the European starling (Sturnus vulgaris), was trapped to explore whether feather Pb burden is greater in birds from urban habitats than rural habitats, as well as whether Pb burdens were correlated with behavior, physiology, and feather development. Across four sites (two rural and two urban), soil Pb concentrations were measured and 197 free-living starlings were captured to measure feather Pb concentrations. Using linear mixed models, this study found that urban starling nestlings had elevated feather Pb burdens compared to rural nestlings. In contrast, there was no correlation between Pb and urbanization in adult birds whose exposure to Pb may reflect a larger spatial range compared to nestlings. For both nestlings and adults, feather Pb was uncorrelated to corticosterone, testosterone, aggressive behavior, or feather growth rates. These findings suggest that starlings may be a useful biomonitoring tool to detect Pb in the local environment, however, the age and spatial range of birds is a critical consideration in applying this tool. Further work is needed to understand the intricate relationship between heavy metals, behavior, morphological development, and physiology in free-living organisms.

Effect of Mycotoxins in Silage on Biogas Production.

Mycotoxins can pose a threat to biogas production as they can contaminate the feedstock used in biogas production, such as agricultural crops and other organic materials. This research study evaluated the contents of deoxynivalenol (DON), zearalenone (ZEA), fumonisin (FUM), and aflatoxin (AFL) mycotoxins in maize silage prior to it being processed in a biogas plant and in digestate produced at the end of the anaerobic digestion (AD) process. In the experiment, three samples of silage were collected from one silage warehouse: Variant 1 = low contamination, Variant 2 = medium contamination, and Variant 3 = heavy contamination, which were subjected to investigation. A significantly reduced biogas production was recorded that was proportional to the increasing contamination with molds, which was primarily due to the AD of silage caused by technologically erroneous silage treatment. The AD was connected with changes in silage composition expressed by the values of VS content, sugar content, lactic acid content, acetic acid content, and the ratio of lactic acid content to acetic acid content. The production of biogas and methane decreased with the increasing contents of NDF, ADF, CF, and lignin. The only exception was Variant 2, in which the content of ADF, CF, and lignin was lower (by 8-11%) than that in Variant 1, and only the content of NDF was higher (by 9%) than that in Variant 1. A secondary factor that also correlated with changes in the composition of the substrate was the development of undesirable organisms, which further contributed to its degradation and to the production of mycotoxins. It was also demonstrated in this study that during the AD process, the tested mycotoxins were degraded, and their content was reduced by 27-100%. Only the variant with low mold contamination showed a DON concentration increase of 27.8%.

Between the genotype and the phenotype lies the microbiome: symbiosis and the making of ‘postgenomic’ knowledge

Emphatic claims of a “microbiome revolution” aside, the study of the gut microbiota and its role in organismal development and evolution is a central feature of so-called postgenomics; namely, a conceptual and/or practical turn in contemporary life sciences, which departs from genetic determinism and reductionism to explore holism, emergentism and complexity in biological knowledge-production. This paper analyses the making of postgenomic knowledge about developmental symbiosis in Drosophila melanogaster by a specific group of microbiome scientists. Drawing from both practical philosophy of science and Science and Technology Studies, the paper documents epistemological questions of artefactuality and representativeness of model organisms as they emerge in the day-to-day labour producing and being produced by the “microbiome revolution." Specifically, the paper builds on all the written and editorial exchanges involved in the troubled publication of a research paper studying the symbiotic role of the microbiota in the flies’ development. These written materials permit us to delimit the network of justifications, evidence, standards of knowledge-production, trust in the tools and research designs that make up the conditions of possibility of a postgenomic fact. More than reframing the organism as a radically novel multiplicity of reactive genomes, we conclude, doing postgenomic research on the microbiota and symbiosis means producing a story that deviates from the scripts embedded into the sociotechnical experimental systems of post-Human Genome Project life sciences.

МОНИТОРИНГ СОСУЩИХ ВРЕДИТЕЛЕЙ В УСЛОВИЯХ ДОНА

The article provides data on the number of sucking pests in 2022. The research was carried out in the conditions of Novocherkassk branch of the experimental field on the technical varie-ty Cvetochniy. Over the past decade, in the Rostov region, due to changes in climatic con-ditions, as well as with the appearance of a large number of lands overgrown with weeds, sucking pests have moved to grapevine plants. Subsequently, damage by sucking pests leads to a decrease in the yield and quality of grapes. The lack of precipitation in June 2022 and the high temperatures in July are factors that did not favorably affect the prevalence of cicada populations. Chemical treatments with insecti-cides were carried out in a timely manner. The effectiveness of insecticide Kinfos was proved against sucking pests of grapes in vineyards of Rostov region. In order to determine an eco-nomically significant threshold for the number of pest populations and make a decision on protective measures, it is advisable to systemat-ically monitor their prevalence. To predict the development of harmful organisms, it is neces-sary to take into account the meteorological conditions of winter and growing season. Ac-cording to the results of monitoring studies, it was found that in the conditions of 2022, three generations of the roseate cicada and one gen-eration of the humpback buffalo, two genera-tions of the grape thrips developed.

Morphological Diversity of the Skull and Lower Jaw of Three Species of Shrews (Eulipotyphla, <i>Sorex</i>) During Depressions and Peaks of Abundance

Ecological conditions can influence the individual development of organisms and morphological variability at the population level. The dimensions and proportions of the skull and lower jaw of immature shrews (Sorex araneus, S. caecutiens, S. minutus) captured in August in overgrown clearings in the middle taiga of north-eastern Europe were dependent on the stage of abundance (“pikes” or “depressions”). For all three species belonging to the same taxocenosis, a statistically significant decrease in skull and jaw measurements was observed against a background of high abundance in captures, and multidimensional morphological niches corresponding to different stages were significantly separated. The parameters of morphological diversity - entropy and a measure of self-organisation were depended on the amplitude of fluctuations in species occurrence, but varied within limits characteristic of mammals. Together with Dehnel’s phenomenon, natural population fluctuations may be one of the main factors determining the nature of the dynamics of individual development and the spatio-temporal variability of morphological diversity in shrews.

Leveraging MODEL‐AD mouse strains to understand the role of toxicant exposures on LOAD risk

AbstractBackgroundLate‐onset Alzheimer’s disease (LOAD) is caused by interactions between genes and environment. However, current mouse models do not fully recapitulate LOAD phenotypes, limiting translatability to clinical needs. To address this, MODEL‐AD (Model Organism Development and Evaluation for Late‐Onset Alzheimer’s Disease) Consortium was established to create and phenotype new mouse models. The IU/JAX/PITT MODEL‐AD Center focuses on developing models with combinations of genetic risk factors, as well as humanizing APP (hAb) and MAPT. One use of these models is to determine the contribution of environmental factors to LOAD risk. Studies show associations between LOAD risk and exposure to ubiquitous environmental neurotoxicants, including arsenic (As), lead (Pb), and cadmium (Cd). All three are ranked in the “Top 10 Toxicants” of public health concern (As #1, Pb #2, Cd #7; ATSDR Toxic Substance Priority List). However, mechanisms driving increased risk are unknown.MethodNovel mouse models were created by genetic engineering or editing in C57BL/6J. Four to 24 months old mice and controls were phenotyped using a human‐relevant battery that includes cognitive performance, imaging, biometrics, transcriptomics, proteomics, metabolomics, neuropathology, and fluid biomarkers. Toxicants (As, Pb, Cd) were delivered using human‐relevant doses in drinking water. Exogenous toxicants (Pb, Cd, As) and endogenous biometals (Zn, Cu, Fe) in brain and blood samples were analyzed by elemental mass spectrometry mapping.ResultMore than 40 mouse models have been created carrying combinations of genetic risk factors in genes including APOE, Trem2, Abca7 and Mthfr. One strain, LOAD2 (triple homozygous for APOE4, Trem2*R47H, and hAb) shows molecular and transcriptomic changes associated with human LOAD. Short‐term exposure to As, Cd, or Pb also modified expression of LOAD‐relevant genes in LOAD2 mice and controls, including App and Vgf, in a toxicant‐specific manner. Elevated toxicant levels were detected in both brain and blood samples from exposed mice.ConclusionThese data indicate that exposure to common environmental toxicants may increase LOAD risk by modifying expression of specific genes and molecular pathways previously implicated in human LOAD. Studies are underway using additional MODEL‐AD models to determine the long‐term effects of neurotoxicant exposures.

Cerebral perfusion is elevated in a novel model of aged hAβKI APOE4 mice

AbstractBackgroundThe Model Organism Development and Evaluation for Late‐Onset Alzheimer’s Disease (MODEL‐AD) Consortium is developing the next generation of Alzheimer’s disease (AD) models based on human genomic and imaging data. Recently, MODEL‐AD has generated a new human Aβ Knock‐In (hAβKI) mouse carrying the APOE4 allele. APOE4 carriers are at increased risk for AD. Previous studies have demonstrated altered cerebrovascular integrity and function. We examined the cerebrovascular function in the hAβKI APOE4 mice at 18mo of age using perfusion‐weighted magnetic resonance imaging (PWI). We investigated brain‐wide perfusion alterations in conjunction with histopathological vessel painting.MethodsContrast‐enhanced PWI MRI (9.4T) was undertaken from hAβKI APOE4 (n = 6) and WT (n = 5) mice at 18mo of age following tail vein cannulation for Gadolinium infusion. Imaging sequences included: T1‐pre and post‐infusion, PWI (10min) and susceptibility‐weighted imaging (SWI) for blood extravasation and iron content. All data were processed using JIM v9 software for maps of cerebral blood flow (CBF), volumes (CBV), time to peak, mean transit time and dynamic susceptibility measures for blood‐brain barrier dysfunction. Manual regions of interest (ROI) were performed for cortex, temporal lobe cortex, dorsal hippocampus and thalamus, and semi‐automatic 30+ regions based on the Allen mouse brain atlas. At the end of the in vivo experiments all mice underwent vessel painting followed by microscopic analyses.ResultsCompared to WT mice at 18mo of age, hAβKI APOE4 mice exhibited elevated CBF in virtually all regions examined. CBF was elevated approx. 16%, 11%, 4% and 23% in the cortex, hippocampus, thalamus and temporal lobe cortex, respectively. CBF was significantly elevated in the retrosplenial and temporal lobe cortices (p<0.05). CBV was also significantly increased in temporal lobe. Ongoing analyses will correlate vascular network measures (density, junctions, length) to PWI metrics as well as to hAβKI only mice.ConclusionsThe 18mo hAβKI APOE4 mouse compared to WT exhibited consistent brain‐wide elevations in cerebrovascular measures. This increase may represent a compensatory mechanism to maintain decreased metabolism that occurs with aging. The MODEL‐AD consortium (UCI/IUSM/JAX) continues to develop new and novel AD mouse models. All data will be made available to AD researchers via the Sage Knowledge Network (https://adknowledgeportal.synapse.org/).

Novel mouse models of late‐onset Alzheimer’s disease

AbstractBackgroundThe Model Organism Development and Evaluation for Late‐onset AD (MODEL‐AD) Consortium was established to generate and characterize more translatable animal models for late‐onset Alzheimer’s disease (LOAD) based on human genetic risk variants. While numerous genetic risk loci for LOAD have been identified, few have been experimentally verified in vivo and in many cases the risk variants have not been validated. The development of new models incorporating LOAD genetic risk should improve our understanding of disease mechanisms and improve preclinical testing of potential therapeutics.MethodCoding and non‐coding LOAD risk variants were prioritized based on human data sets, with the goal of targeting diverse pathways (e.g., neuroinflammation, vascular risk, metabolic function, lipid homeostasis). Risk variants in Abca7, Adamts4, Bin1, Erc2, Mthfr, Mtmr4, Plcg2, Ptk2b, Slc6a17, Snx1, Sorl1 and other loci were engineered into mouse models expressing humanized APOE4 and the Trem2*R47H risk variant; in more recent models, a humanized Abeta allele was also included. A novel transcriptomic panel, based on clinical LOAD samples (Preuss et al, 2020) was used to evaluate how well each model replicated clinical transcriptomic changes with disease. Models were aligned to ROSMAP clinical subtypes.ResultWe have identified specific human AD‐related pathways disrupted in an age‐dependent manner in these novel mouse models. Specifically, mouse models carrying human AD risk variants Abca7*A1527G, Mthfr*C677T, and Plcg2*M28L exhibited transcriptomics changes similar to those seen in LOAD patients. Most models could be readily matched to either the inflammatory or non‐inflammatory subtype.ConclusionWe have prioritized mouse models expressing LOAD risk variants in Abca7, Mthfr, and Plcg2 for comprehensive phenotyping using clinically relevant measures including transcriptomics and proteomics, biomarkers, neuropathology and in vivo imaging at advanced ages (24 months). Ongoing projects will use human data to guide how to combine alleles to create models that match multi‐omic signatures of AD subtypes and test the effects of environmental risk factors such as high‐fat diet. Through this effort we aim to develop improved models for testing targeted therapeutics.

Cerebral perfusion is elevated in a novel model of aged hAβKI APOE4 mice

AbstractBackgroundThe Model Organism Development and Evaluation for Late‐Onset Alzheimer’s Disease (MODEL‐AD) Consortium is developing the next generation of Alzheimer’s disease (AD) models based on human genomic and imaging data. Recently, MODEL‐AD has generated a new human Aß Knock‐In (hAßKI) mouse carrying the APOE4 allele. APOE4 carriers are at increased risk for AD. Previous studies have demonstrated altered cerebrovascular integrity and function. We examined the cerebrovascular function in the hAßKI APOE4 mice at 18mo of age using perfusion‐weighted magnetic resonance imaging (PWI). We investigated brain‐wide perfusion alterations in conjunction with histopathological vessel painting.MethodContrast‐enhanced PWI MRI (9.4T) was undertaken from hAßKI APOE4 (n = 6) and WT (n = 5) mice at 18mo of age following tail vein cannulation for Gadolinium infusion. Imaging sequences included: T1‐pre and post‐infusion, PWI (10min) and susceptibility‐weighted imaging (SWI) for blood extravasation and iron content. All data were processed using JIM v9 software for maps of cerebral blood flow (CBF), volumes (CBV), time to peak, mean transit time and dynamic susceptibility measures for blood‐brain barrier dysfunction. Manual regions of interest (ROI) were performed for cortex, temporal lobe cortex, dorsal hippocampus and thalamus, and semi‐automatic 30+ regions based on the Allen mouse brain atlas. At the end of the in vivo experiments all mice underwent vessel painting followed by microscopic analyses.ResultCompared to WT mice at 18mo of age, hAßKI APOE4 mice exhibited elevated CBF in virtually all regions examined. CBF was elevated approx. 16%, 11%, 4% and 23% in the cortex, hippocampus, thalamus and temporal lobe cortex, respectively. CBF was significantly elevated in the retrosplenial and temporal lobe cortices (p<0.05). CBV was also significantly increased in temporal lobe. Ongoing analyses will correlate vascular network measures (density, junctions, length) to PWI metrics as well as to hAßKI only mice.ConclusionThe 18mo hAßKI APOE4 mouse compared to WT exhibited consistent brain‐wide elevations in cerebrovascular measures. This increase may represent a compensatory mechanism to maintain decreased metabolism that occurs with aging. The MODEL‐AD consortium (UCI/IUSM/JAX) continues to develop new and novel AD mouse models. All data will be made available to AD researchers via the Sage Knowledge Network (https://adknowledgeportal.synapse.org/).

Fibroblast Growth Factor 21: A Fascinating Perspective on the Regulation of Muscle Metabolism.

Fibroblast growth factor 21 (FGF21) plays a vital role in normal eukaryotic organism development and homeostatic metabolism under the influence of internal and external factors such as endogenous hormone changes and exogenous stimuli. Over the last few decades, comprehensive studies have revealed the key role of FGF21 in regulating many fundamental metabolic pathways, including the muscle stress response, insulin signaling transmission, and muscle development. By coordinating these metabolic pathways, FGF21 is thought to contribute to acclimating to a stressful environment and the subsequent recovery of cell and tissue homeostasis. With the emphasis on FGF21, we extensively reviewed the research findings on the production and regulation of FGF21 and its role in muscle metabolism. We also emphasize how the FGF21 metabolic networks mediate mitochondrial dysfunction, glycogen consumption, and myogenic development and investigate prospective directions for the functional exploitation of FGF21 and its downstream effectors, such as the mammalian target of rapamycin (mTOR).

Ovarian ERβ cistrome and transcriptome reveal chromatin interaction with LRH-1

BackgroundEstrogen receptor beta (ERβ, Esr2) plays a pivotal role in folliculogenesis and ovulation, yet its exact mechanism of action is mainly uncharacterized.ResultsWe here performed ERβ ChIP-sequencing of mouse ovaries followed by complementary RNA-sequencing of wild-type and ERβ knockout ovaries. By integrating the ERβ cistrome and transcriptome, we identified its direct target genes and enriched biological functions in the ovary. This demonstrated its strong impact on genes regulating organism development, cell migration, lipid metabolism, response to hypoxia, and response to estrogen. Cell-type deconvolution analysis of the bulk RNA-seq data revealed a decrease in luteal cells and an increased proportion of theca cells and a specific type of cumulus cells upon ERβ loss. Moreover, we identified a significant overlap with the gene regulatory network of liver receptor homolog 1 (LRH-1, Nr5a2) and showed that ERβ and LRH-1 extensively bound to the same chromatin locations in granulosa cells. Using ChIP-reChIP, we corroborated simultaneous ERβ and LRH-1 co-binding at the ERβ-repressed gene Greb1 but not at the ERβ-upregulated genes Cyp11a1 and Fkbp5. Transactivation assay experimentation further showed that ERβ and LRH-1 can inhibit their respective transcriptional activity at classical response elements.ConclusionsBy characterizing the genome-wide endogenous ERβ chromatin binding, gene regulations, and extensive crosstalk between ERβ and LRH-1, along with experimental corroborations, our data offer genome-wide mechanistic underpinnings of ovarian physiology and fertility.