Biology subjects

Daugherty, A.

Publications and source records attributed to Daugherty, A..

34 records · Page 2Linked to original sources

bioRxiv2023

A (Sub)field Guide to Quality Control in Hippocampal Subfield Segmentation on High-resolution T2-weighted MRI

Inquiries into properties of brain structure and function have progressed due to developments in magnetic resonance imaging (MRI). To sustain progress in investigating and quantifying neuroanatomical details in vivo, the reliability and validity of brain measurements are paramount. Quality control (QC) is a set of procedures for mitigating errors and ensuring the validity and reliability of brain measurements. Despite its importance, there is little guidance on best QC practices and reporting procedures. The study of hippocampal subfields in vivo is a critical case for QC because of their small size, inter-dependent boundary definitions, and common artifacts in the MRI data used for subfield measurements. We addressed this gap by surveying the broader scientific community studying hippocampal subfields on their views and approaches to QC. We received responses from 37 investigators spanning 10 countries, covering different career stages, and studying both healthy and pathological development and aging. In this sample, 81% of researchers considered QC to be very important or important, and 19% viewed it as fairly important. Despite this, only 46% of researchers reported on their QC processes in prior publications. In many instances, lack of reporting appeared due to ambiguous guidance on relevant details and guidance for reporting, rather than absence of QC. Here, we provide recommendations for correcting errors to maximize reliability and minimize bias. We also summarize threats to segmentation accuracy, review common QC methods, and make recommendations for best practices and reporting in publications. Implementing the recommended QC practices will collectively improve inferences to the larger population, as well as have implications for clinical practice and public health.

neuroscience↗

bioRxiv2023

β-aminopropionitrile Induces Distinct Pathologies in the Ascending and Descending Thoracic Aortic Regions of Young Mice

BACKGROUND{beta}-aminopropionitrile (BAPN) is a pharmacological inhibitor of lysyl oxidase and lysyl oxidase-like proteins. Administration of BAPN promotes aortopathies, although there is a paucity of data on experimental conditions to generate pathology. The objective of this study was to define experimental parameters and determine whether equivalent or variable aortopathies were generated throughout the aortic tree during BAPN administration in mice. METHODSBAPN was administered in drinking water for a period ranging from 1 to 12 weeks. The impacts of BAPN were first assessed with regard to dose, strain, age, and sex. BAPN-induced aortic pathological characterization was conducted using histology and immunostaining. To investigate the mechanistic basis of regional heterogeneity, ascending and descending thoracic aortas were harvested after one week of BAPN administration before the appearance of overt pathology. RESULTSBAPN-induced aortic rupture predominantly occurred or originated in the descending thoracic aorta in young C57BL/6J or N mice. No apparent differences were found between male and female mice. For mice surviving 12 weeks of BAPN administration, profound dilatation was consistently observed in the ascending region, while there were more heterogeneous changes in the descending thoracic region. Pathological features were distinct between the ascending and descending thoracic regions. Aortic pathology in the ascending region was characterized by luminal dilatation and elastic fiber disruption throughout the media. The descending thoracic region frequently had dissections with false lumen formation, collagen deposition, and remodeling of the wall surrounding the false lumen. Cells surrounding the false lumen were predominantly positive for -smooth muscle actin. One week of BAPN administration compromised contractile properties in both regions equivalently, and RNA sequencing did not show obvious differences between the two aortic regions in smooth muscle cell markers, cell proliferation markers, and extracellular components. CONCLUSIONSBAPN-induced pathologies show distinct, heterogeneous features within and between ascending and descending aortic regions in mice.

pathology↗

bioRxiv2023

Regional Heterogeneity of Aortic Histology and Transcriptomes in Young Cynomolgus Monkeys

BackgroundThe regional heterogeneity of vascular components and transcriptomes is an important determinant of aortic biology. This notion has been explored in multiple mouse studies. In the present study, we examined the regional heterogeneity of aortas in non-human primates. MethodsAortic samples were harvested from the ascending, descending, suprarenal, and infrarenal regions of young control monkeys and adult monkeys provided with high fructose for 3 years. The regional heterogeneity of aortic structure and transcriptomes was examined by histological and bulk RNA sequencing analyses. ResultsImmunostaining of CD31 and SMA revealed that endothelial and smooth muscle cells were distributed homogeneously across the aortic regions. In contrast, elastic fibers were less abundant and dispersed in the infrarenal aorta compared to other regions and associated with collagen deposition. Bulk RNA sequencing identified a distinct transcriptome related to the Notch signaling pathway in the infrarenal aorta with significantly increased NOTCH3 mRNA compared to other regions. Immunostaining revealed that NOTCH3 protein was increased in the media of the infrarenal aorta. The abundance of medial NOTCH3 was positively correlated with the dispersion of elastic fibers. Adult cynomolgus monkeys provided with high fructose displayed vascular wall remodeling, such as smooth muscle cell loss and elastic fiber disruption, predominantly in the infrarenal region. The correlation between NOTCH3 and elastic fiber dispersion was enhanced in these monkeys. ConclusionsAortas of young cynomolgus monkeys display regional heterogeneity of their transcriptome and the structure of elastin and collagens. Elastic fibers in the infrarenal aorta are dispersed along with upregulation of medial NOTCH3. HIGHLIGHTS- The present study determined the regional heterogeneity of aortas from cynomolgus monkeys. - Aortas of young cynomolgus monkeys displayed region-specific aortic structure and transcriptomes. - Elastic fibers were dispersed in the infrarenal aorta along with increased NOTCH3 abundance in the media. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/530901v2_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@164c52corg.highwire.dtl.DTLVardef@ccfda8org.highwire.dtl.DTLVardef@213064org.highwire.dtl.DTLVardef@f007c3_HPS_FORMAT_FIGEXP M_FIG C_FIG

pathology↗

bioRxiv2022

Functional Exploration of Conserved Sequences in the Distal Face of Angiotensinogen

BackgroundAngiotensinogen (AGT) is an essential component in the renin-angiotensin system. AGT has highly conserved sequences in the loop and {beta}-sheet regions among species; however, their functions have not been studied. MethodsAdeno-associated viral vector (AAV) serotype 2/8 encoding mouse AGT with mutations of conserved sequences in the loop (AAV.loop-Mut), {beta}-sheet (AAV.{beta}sheet-Mut), or both regions (AAV.loop/{beta}sheet-Mut) were injected into male hepatocyte-specific AGT deficient (hepAGT-/-) mice in an LDL receptor -/- background. AAV containing mouse wild-type AGT (AAV.mAGT) or a null vector (AAV.null) were used as controls. Two weeks after AAV administration, all mice were fed a Western diet for 12 weeks. To determine how AGT secretion is regulated in hepatocytes, AAVs containing the above mutations were transducted into HepG2 cells. ResultsIn hepAGT-/- mice infected with AAV.loop-Mut or {beta}sheet-Mut, plasma AGT concentrations, systolic blood pressure, and atherosclerosis were comparable to those in AAV.mAGT-infected mice. Surprisingly, plasma AGT concentrations, systolic blood pressure, and atherosclerotic lesion size in hepAGT-/- mice infected with AAV.loop/{beta}sheet-Mut were not different from mice infected with AAV.null. In contrast, hepatic Agt mRNA abundance was elevated to a comparable magnitude as AAV.mAGT-infected mice. Immunostaining showed that AGT protein was accumulated trol and AAV containing wild-type mouse AGT as a positive control. We have demonstra ted consistently in this and previous studies tht located in the endoplasmic reticulum. ConclusionsThe conserved sequences in either the loop or {beta}-sheet region individually have no effect on AGT regulation, but the conserved sequences in both regions synergistically contribute to the secretion of AGT from hepatocytes. HIGHLIGHTSO_LIThe loop and {beta}-sheet regions in the distal face of angiotensinogen (AGT) have highly conserved sequences across species. C_LIO_LIMutations on either the loop or {beta}-sheet regions do not affect plasma AGT concentrations, blood pressure, and atherosclerosis in hypercholesterolemic mice. C_LIO_LIThe conserved sequences in the loop and {beta}-sheet regions regulate the secretion of AGT from hepatocytes synergistically in vivo and in cultured cells. C_LI

molecular biology↗

bioRxiv2021

Renal Angiotensinogen in Nonhuman Primates is Predominantly Liver-Derived

AGT (Angiotensinogen) is the unique substrate of the renin-angiotensin system. Liver is the primary source of circulating AGT. The present study determined whether hepatocyte-derived AGT regulates renal AGT accumulation by injecting ASO (antisense oligonucleotides) targeting hepatocyte-derived AGT (GalNAc AGT ASO) into female cynomolgus monkeys. Hepatocyte-specific inhibition of AGT led to profound reductions of plasma AGT concentrations. AGT protein in S1 and S2 of renal proximal tubules was greatly diminished by GalNAc AGT ASO. Given the similarity between nonhuman primates and human, our findings support the notion that renal AGT is predominantly derived from liver, and liver regulates renal angiotensin II production in humans. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/444555v2_ufig1.gif" ALT="Figure 1"> View larger version (57K): org.highwire.dtl.DTLVardef@292f5aorg.highwire.dtl.DTLVardef@1e3e0aborg.highwire.dtl.DTLVardef@1b331e3org.highwire.dtl.DTLVardef@1904dba_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Losartan Increases Survival of the Fbn1mgR/mgR Mouse Model of Marfan Syndrome in and Age-Dependent Manner

Clinical trials investigating angiotensin receptor blockers (ARB) for attenuation of thoracic aortic aneurysm in people with Marfan syndrome have demonstrated variable efficacy. The primary objective of this study was to determine whether the age of mice at the time of losartan initiation affected mortality in fibrillin-1 hypomorphic (Fbn1mgR/mgR) mice. Male (n=40) and female (n=28) Fbn1mgR/mgR mice were randomized to receive losartan in drinking water (0.6 g/L) starting at either 24 or 50 days of age. Controls included Fbn1mgR/mgR mice (20M, 14F) and wild type (15M, 15F) littermates who were not administered the drug. Mortality of Fbn1mgR/mgR males receiving losartan at postnatal day 24 (P24) was not different from wild type controls (p=0.138). Survival of Fbn1mgR/mgR males administered losartan at P50 was not different compared to Fbn1mgR/mgR males receiving no drug (p=0.194) and decreased compared to wild type mice (p=0.002). Survival analysis after P50 demonstrated increased survival of Fbn1mgR/mgR males administered losartan at P50 compared to Fbn1mgR/mgR mice receiving no drug (p=0.017). Age is a critical variable that affects the therapeutic efficacy of losartan in male Fbn1mgR/mgR mice. Since overall mortality in female Fbn1mgR/mgR mice was lower than in male Fbn1mgR/mgR mice, a survival benefit with losartan was not detected in females.

physiology↗

bioRxiv2021

GSDMD Deficiency Protects Against Aortic Rupture

ObjectiveAortic ruptures are fatal consequences of aortic aneurysms with macrophage accumulation being a hallmark at the site of ruptures. Pyroptosis is critical in macrophage-mediated inflammation. This study determined effects of pyroptosis on aortic dilation and rupture using GSDMD deficient mice. Approach and ResultsIn an initial study, male Gsdmd+/+ and Gsdmd-/- mice in C57BL/6J background (8 - 10 weeks old) were infected with adeno-associated viral vectors encoding mouse PCSK9D377Y gain-of-function mutation and fed a Western diet to induce hypercholesterolemia. After two weeks of AAV infection, angiotensin II (AngII, 1 {micro}g/kg/min) was infused. During the 4 weeks of AngII infusion, 5 of 13 Gsdmd+/+ mice died of aortic rupture, whereas no aortic rupture occurred in Gsdmd-/- mice. In surviving mice, no differences in either ascending or abdominal aortic dilation were observed between Gsdmd+/+ and Gsdmd-/- mice. To determine whether protection of GSDMD deficiency against aortic rupture is specific to AngII infusion, we subsequently examined aortic pathologies in mice administered beta-aminopropionitrile (BAPN). BAPN (0.5% wt/vol) was administered in drinking water to male Gsdmd+/+ and Gsdmd-/- mice (4 weeks old) for 4 weeks. Six of 13 Gsdmd+/+ mice died of aortic rupture, whereas no aortic rupture occurred in Gsdmd-/- mice. In mice survived, no differences of diameters in the ascending, arch, or abdominal aortic regions were observed between Gsdmd+/+ and Gsdmd-/- mice. ConclusionsGSDMD deficiency protects against AngII or BAPN-induced aortic ruptures in mice. HighlightsO_LIGSDMD deficiency protects against angiotensin II-induced aortic rupture in hypercholesterolemic mice. C_LIO_LIGSDMD deficiency protects against beta-aminopropionitrile (BAPN)-induced aortic dissection and rupture in C57BL/6J mice. C_LI

molecular biology↗

bioRxiv2020

Authentication of In Situ Measurements for Thoracic Aortic Aneurysms in Mice

Aortic diameter is a standard parameter for defining disease severity of thoracic aortic aneurysms. In mouse studies, aortic diameters can be measured in situ directly, but this approach has a potential confounder of underestimation due to the absence of physiological arterial blood pressure. In the present study, we developed an in situ approach for authentic aortic measurements. Thoracic aortic aneurysms were induced by beta-aminopropionitrile (BAPN, 0.5% wt/vol) administration in 4-week-old male C57BL/6J mice. Ultrasonography was performed to examine aortic dimensions, and mice with thoracic aortic dilatations were terminated subsequently. After saline perfusion through the left ventricle, periaortic tissues were removed to expose thoracic aortas. Optimal cutting temperature (OCT) compound was injected via the left ventricle to maintain aortic patency. In situ aortic images were captured pre- and post-OCT injection. In mice with severe thoracic aortic aneurysms, smaller aortic diameters were observed prior to OCT injection compared to ultrasound measurements, while aortic diameters in situ after OCT were comparable to diameters measured using ultrasound. A telemetry system demonstrated that maximal luminal pressures during 150 ul of OCT injection were 90 mmHg. Immunostaining for CD31 revealed that endothelial cells were preserved in the intima after OCT injection. These results indicate that OCT injection does not cause aortic damages due to excess pressures. In conclusion, in situ imaging with OCT injection provides authentic aortic measurements without overt aortic damage in mice with thoracic aortic aneurysms.

pathology↗

bioRxiv2020

Effects of Endogenous Angiotensin II on Abdominal Aortic Aneurysms and Atherosclerosis in Angiotensin II-infused Mice

Angiotensin II (AngII), a major effector of the renin-angiotensin system, exerts critical roles in regulating vascular function. AngII infusion induces abdominal aortic aneurysms (AAAs) and exacerbates atherosclerosis in hypercholesterolemic mice. We determined the effects of AngII infusion on endogenous AngII regulation and AngII-mediated AAAs and atherosclerosis. AngII infusion increased renal, but not plasma, AngII concentrations in male mice. AngI concentrations were decreased modestly in kidney, but more profoundly in plasma, during AngII infusion. Bovine AngII (DRVYVHPF) has one amino acid difference from mouse AngII (DRVYIHPF) that can be distinguished by LC-MS/MS. Therefore, we determined exogenous versus endogenous peptides in mice infused with bovine AngII. Bovine AngII infusion reduced endogenous renal AngII concentrations. To determine whether the residual endogenous AngII exerted an effect on AAAs and atherosclerosis in mice infused with AngII, aliskiren (a direct renin inhibitor) was administered to AngII-infused male LDL receptor deficient mice. Although aliskiren did not attenuate AAAs in AngII-infused mice, atherosclerotic lesion size was reduced. In conclusion, endogenous AngII concentrations are reduced during AngII infusion but still contribute to atherosclerosis, but not AAA, in AngII-infused hypercholesterolemic mice.

pathology↗

bioRxiv2020

Effects of Renin-Angiotensin Inhibition on ACE2 and TMPRSS2 Expression

Angiotensin-converting enzyme 2 (ACE2), a component of the renin-angiotensin system, is a receptor for SARS-CoV-2, the virus that causes COVID-19. To determine whether the renin-angiotensin inhibition regulates ACE2 expression, either enalapril (an angiotensin-converting enzyme inhibitor) or losartan (an AT1 receptor blocker) was infused subcutaneously to male C57BL/6J mice for two weeks. Neither enalapril nor losartan changed abundance of ACE2 mRNA in lung, ileum, kidney, and heart. Viral entry also depends on transmembrane protease serine 2 (TMPRSS2) to prime the S protein. TMPRSS2 mRNA was abundant in lungs and ileum, modest in kidney, but barely detectable in heart. TMPRSS2 mRNA abundance was not altered by either enalapril or losartan in any of the 4 tissues. Next, we determined whether depletion of angiotensinogen (AGT), the unique substrate of the renin-angiotensin system, changes ACE2 and TMPRSS2 mRNA abundance. AGT antisense oligonucleotides (ASO) were injected subcutaneously to male C57BL/6J mice for 3 weeks. Abundance of ACE2 mRNA was unchanged in any of the 4 tissues, but TMPRSS2 mRNA was significantly decreased in lungs. Our data support that the renin-angiotensin inhibition does not regulate ACE2 and hence are not likely to increase risk for COVID-19.

molecular biology↗

bioRxiv2020

Inhibition of Angiotensin II Dependent AT1a Receptor Stimulation Attenuates Thoracic Aortic Pathology in Fibrillin-1C1041G/+ Mice

Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=157 SRC="FIGDIR/small/127670v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@8e7c32org.highwire.dtl.DTLVardef@7bf57aorg.highwire.dtl.DTLVardef@312d3forg.highwire.dtl.DTLVardef@9198bd_HPS_FORMAT_FIGEXP M_FIG C_FIG ObjectiveA cardinal feature of Marfan syndrome is thoracic aortic aneurysm (TAA). The contribution of ligand-dependent stimulation of angiotensin II receptor type 1a (AT1aR) to TAA progression remains controversial because the beneficial effects of angiotensin receptor blockers have been ascribed to off-target effects. This study used genetic and pharmacologic modes of attenuating angiotensin receptor and ligand, respectively, to determine their roles on TAA in mice with fibrillin-1 haploinsufficiency (Fbn1C1041G/+). Approach and ResultsTAA in Fbn1C1041G/+ mice were determined in both sexes and found to be strikingly sexual dimorphic. Males displayed progressive dilation over 12 months while ascending aortic dilation in Fbn1C1041G/+ females did not differ significantly from wild type mice. To determine the role of AT1aR, Fbn1C1041G/+ mice that were either +/+ or -/- for AT1aR were generated. AT1aR deletion reduced progressive expansion of ascending aorta and aortic root diameter from 1 to 12 months of age in males. Medial thickening and elastin fragmentation were attenuated. An antisense oligonucleotide against angiotensinogen (AGT-ASO) was administered to male Fbn1C1041G/+ mice to determine the effects of angiotensin II depletion. AGT-ASO administration, at doses that markedly reduced plasma AGT concentrations, attenuated progressive dilation of the ascending aorta and aortic root. AGT-ASO also reduced medial thickening and elastin fragmentation. ConclusionsGenetic approaches to delete AT1aR and deplete AngII production exerted similar effects in attenuating pathology in the proximal thoracic aorta of male Fbn1C1041G/+ mice. These data are consistent with ligand (AngII) dependent stimulation of AT1aR being responsible for aortic disease progression. HighlightsO_LIProfound sexual dimorphism of aortic disease occurs in Fbn1C1041G/+ mice, with female mice being more resistant and male mice being more susceptible. C_LIO_LIInhibition of the AngII-AT1aR axis attenuates aortic pathology in male Fbn1C1041G/+ mice. C_LIO_LIAntisense oligonucleotides targeting angiotensinogen deplete plasma angiotensinogen and attenuate thoracic aortic aneurysms. C_LI

physiology↗

bioRxiv2020

Bitter Melon (Momordica Charantia) Supplementation Has no Effect on Hypercholesterolemia and Atherosclerosis in Mice

Momordica Charantia, commonly known as bitter melon, has been reported to ameliorate diet-induced obesity and dyslipidemia. However, the effects of M. Charantia on atherosclerosis have not been determined. This study investigated the effects of M. Charantia on diet-induced atherosclerosis in LDL receptor deficient mice. Female mice (6-8 weeks old) were fed a saturated fat-enriched diet. In group 1, mice were fed this diet alone, while mice in groups 2 and 3 were fed the diet supplemented with M. Charantia either 0.1% or 1% by weight, for 12 weeks. No significant differences in body weights were observed among the 3 groups. There were also no significant differences in plasma cholesterol concentrations among the 3 groups. To determine the effects on atherosclerosis, lesion areas were measured on aortic intima by an en face technique. Neither dose of M. Charantia supplementation changed atherosclerosis development.Competing Interest StatementThe authors have declared no competing interest.View Full Text

physiology↗

bioRxiv2020

Ultrasound Monitoring of Descending Aortic Aneurysms and Dissections in Mice

Several modalities, such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound, are available to visualize mouse aortas.1-3 CT and MRI enable us to obtain reliable images of the aorta and its branches. However, CT requires vascular contrast and MRI is procedurally complex. Thus, these modalities are used only occasionally for in vivo monitoring of mouse studies. High frequency ultrasonography is a common approach for aortic monitoring in mice.4 The standard ultrasound approach using a para-sternal view can visualize the aortic root, ascending aorta, and aortic arch, while this approach cannot visualize the descending region due to the presence of lungs and ribs. Therefore, the ability to perform in vivo monitoring of descending aortic diseases in mice has been an impediment. This study reports a para-spinal dorsal approach for ultrasound imaging of mouse descending aortas.

pathology↗

bioRxiv2020

Functional Importance of Second Heart Field-derived Cells During Thoracic Aortic Aneurysm Formation

BackgroundThe ascending aorta is a common location for aneurysm and dissection. This aortic region is populated by a mosaic of medial and adventitial cells that are embryonically derived from either the second heart field (SHF) or the cardiac neural crest. SHF-derived cells populate areas that coincide with the spatial specificity of thoracic aortopathies. The purpose of this study was to determine whether and how SHF-derived cells contribute to ascending aortopathies. MethodsAscending aortic pathologies were examined in patients with sporadic thoracic aortopathies and angiotensin II (AngII)-infused mice. Ascending aortas without overt pathology from AngII-infused mice were subjected to mass spectrometry assisted proteomics, and molecular features of SHF-derived cells were determined by single cell transcriptomic analyses. Genetic deletion of either low-density lipoprotein receptor-related protein 1 (Lrp1) or transforming growth factor-{beta} receptor 2 (Tgfbr2) in SHF- derived cells was conducted to examine the impact of SHF-derived cells on vascular integrity. ResultsPathologies in human ascending aortic aneurysmal tissues were predominant in outer medial layers and adventitia. This gradient was mimicked in mouse aortas following AngII infusion that was coincident with the distribution of SHF-derived cells. Proteomics indicated that brief AngII infusion, prior to overt pathology, evoked downregulation of SMC proteins and differential expression of extracellular matrix proteins, including several LRP1 ligands. LRP1 deletion in SHF-derived cells augmented AngII-induced ascending aortic aneurysm and rupture. Single cell transcriptomic analysis revealed that brief AngII infusion decreased Lrp1 and Tgfbr2 mRNA abundance in SHF-derived cells and induced a unique fibroblast population with low abundance of Tgfbr2 mRNA. SHF-specific Tgfbr2 deletion led to embryonic lethality at E12.5 with dilatation of the outflow tract and retroperitoneal hemorrhage. Integration of proteomic and single cell transcriptomics results identified plasminogen activator inhibitor 1 (PAI1) as the most increased protein in SHF-derived SMCs and fibroblasts during AngII infusion. Immunostaining revealed a transmural gradient of PAI1 in both ascending aortas of AngII-infused mice and human ascending aneurysmal aortas that mimicked the gradient of medial and adventitial pathologies. ConclusionSHF-derived cells exert a critical role in maintaining vascular integrity through LRP1 and TGF-{beta} signaling associated with increases of aortic PAI1. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=89 SRC="FIGDIR/small/930917v6_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@185e3d9org.highwire.dtl.DTLVardef@131d702org.highwire.dtl.DTLVardef@11afa42org.highwire.dtl.DTLVardef@242786_HPS_FORMAT_FIGEXP M_FIG C_FIG Clinical PerspectiveO_ST_ABSWhat is new?C_ST_ABS- SHF-derived SMCs and fibroblasts associate with AngII-induced aortic pathologies. - AngII induces a distinct fibroblast sub-cluster that is less abundant for mRNAs related to major extracellular components and TGF{beta} ligands and receptors, but more abundant for proliferative genes. - TGFBR2 deletion in SHF-derived cells are embryonic lethal with significant dilatation of the outflow tract in mice. - SHF-specific deletion of LRP1 leads to aortic pathologies in mice, supporting the importance of SHF-derived cells in maintaining ascending aortic wall integrity. What are the clinical implications?- Heterogeneity of the embryonic origins of SMCs and fibroblasts contributes to complex mechanisms of vasculopathy formation, which should be considered when investigating the pathogenesis of thoracic aortopathies.

pathology↗

bioRxiv2020

Hypercholesterolemia Accelerates the Initiation and Progression of Angiotensin II-induced Abdominal Aortic Aneurysms

ObjectiveThis study determined whether hypercholesterolemia would contribute to both the initiation and progression of angiotensin (Ang)II-induced abdominal aortic aneurysms (AAAs) in mice. Methods and ResultsTo determine whether hypercholesterolemia accelerates the initiation of AAAs, male low-density lipoprotein (LDL) receptor -/- mice were either fed one week of Western diet prior to starting AngII infusion or initiated Western diet one week after starting AngII infusion. During the first week of AngII infusion, mice fed normal diet had less luminal expansion of the suprarenal aorta compared to those initiated Western diet after the first week of AngII infusion. The two groups achieved comparable luminal dilation on week 2 through week 6 of AngII infusion as monitored by ultrasound. To determine whether hypercholesterolemia contributed to the progression of established AAAs, male LDL receptor -/- mice were fed Western diet and infused with AngII for 4 weeks. Mice with established AAAs were then stratified into two groups based on luminal diameters measured by ultrasound. While AngII infusion was continued for another 8 weeks in both groups, mice in one group were continuously fed Western diet, but diet in the other group was switched to normal laboratory diet. In the latter group, plasma cholesterol concentrations were reduced rapidly to approximately 500 mg/dl within one week after the diet was switched from Western diet to normal laboratory diet. Luminal expansion progressed constantly in mice continuously fed Western diet, whereas no continuous expansion was detected in mice that were switched to normal laboratory diet. ConclusionsHypercholesterolemia accelerates both the initiation of AAAs and progression of established AAAs in AngII-infused male LDL receptor -/- mice. Clinical RelevanceHypercholesterolemia is modestly associated with AAAs in observational or retrospective clinical studies. It is not feasible to study whether hypercholesterolemia contributes to the initiation of AAAs or progression of established AAAs in human. This study using AngII-induced AAA mouse model provides solid evidence that hypercholesterolemia contributes to both the initiation and progression of AAAs, supporting that statin therapy at any stage of AAA development may be beneficial to hypercholesterolemic patients with AAAs.

pathology↗

bioRxiv2019

The Two Amino Acids Proximate to the Renin Cleavage Site of Human Angiotensinogen Do Not Affect Angiotensin II-mediated Functions in Mice

ObjectiveRenin cleavage of angiotensinogen (AGT) has species specificity. Since the residues at positions 11 and 12 of AGT are different between human and mouse AGT, we determined whether these two residues in AGT affect renin cleavage and angiotensin II-mediated functions using an adeno-associated viral (AAV) approach for manipulating AGT in vivo. Approach and ResultsHepatocyte-specific AGT deficient (hepAGT-/-) mice in an LDL receptor -/- background were infected with AAVs containing a null insert, human AGT, or mouse AGT expressing the same residues of the human protein at positions 11 and 12 [mouse AGT (L11V;Y12I)]. Expression of human AGT in hepAGT-/- mice led to high plasma human AGT concentrations without changes in plasma mouse endogenous AGT, plasma renin concentrations, blood pressure, or atherosclerosis. This is consistent with human AGT not being cleaved by mouse renin. To determine whether the residues at positions 11 and 12 in human AGT lead to the inability of mouse renin to cleave human AGT, hepAGT-/- mice were injected with AAV encoding mouse AGT (L11V;Y12I). Expression of mouse AGT (L11V;Y12I) resulted in increased plasma mouse AGT concentrations, reduced renin concentrations, and increased renal AngII concentrations that were comparable to their concentrations in hepAGT+/+ mice. This mouse AGT variant increased blood pressure and atherosclerosis in hepAGT-/- mice to the magnitude of hepAGT+/+ mice. ConclusionReplacement of L11 and Y12 to V11 and I12, respectively, in mouse AGT does not affect renin cleavage and AngII-mediated functions in mice. HIGHLIGHTSO_LIHuman AGT is not cleaved by mouse renin and does not change AngII-mediated functions in hepatocyte-specific AGT -/- mice. C_LIO_LIReplacement of the N-terminal amino acids at 11 and 12 positions from mouse to human AGT does not affect renin cleavage and AngII-mediated functions in hepatocyte-specific AGT -/- mice. C_LI

pathology↗