Biology subjects

Rubinelli, L.

Publications and source records attributed to Rubinelli, L..

5 recordsLinked to original sources

bioRxiv2025

Ablation of Prdm16 and beige fat causes vascular remodeling and elevated blood pressure

While excess adiposity is a major risk factor for hypertension and cardiovascular disease, brown fat is associated with protection from these pathologies. Whether brown fat has a causal role in this process and the underlying molecular mechanisms remain unknown. Here we investigate the role of murine beige fat, as a model of inducible brown fat in humans, in adipocyte-vascular crosstalk. Using mice with an adipocyte-specific deletion of PRDM16, resulting in a loss of beige adipocyte identity, we discover a dramatic remodeling of perivascular adipose tissue, increased vascular reactivity and elevated blood pressure. We further show that the circulating enzyme Qsox1 is de-repressed in Prdm16-deficient adipocytes, and deletion of Qsox1 in PRDM16cKO mice rescues vascular fibrosis and reactivity. These results demonstrate a key new role for beige adipocytes in blood pressure regulation and identify Qsox1 as an important mediator of adipocyte-vascular crosstalk.

physiology↗

bioRxiv2025

DNA-based delivery of incretin receptor agonists using MYO Technology leads to durable weight loss in a diet-induced obesity model

Therapeutic proteins have seen a substantial increase in clinical development and use across many disease areas. Despite their broad applicability, significant drawbacks limit access to many of these drugs, including: i) high manufacturing costs; ii) administration via time-consuming infusions; iii) frequent dosing, sometimes even daily; and iv) requirements for low temperature storage. MYO Technology was developed to overcome these barriers. The MYO Technology platform consists of therapeutic-encoding plasmid DNA (pDNA), and a proprietary medical device for intramuscular injection and delivery of electrical pulses. These pulses enable the in vivo electroporation of muscle cells and uptake of injected pDNA, leading to the production, secretion, and delivery of the therapeutic protein into peripheral circulation. MYO Technology offers several advantages over standard delivery of therapeutic proteins; pDNA manufacturing is a simpler and less specialized process compared to protein manufacturing, and pDNA is very stable and lacks most cold chain requirements. Furthermore, administration using MYO Technology takes only a few minutes, and the serum level of a therapeutic protein can potentially be maintained for many months without the need for redosing. Incretin receptor agonists (IRAs) are a class of therapeutic proteins that have recently come to prominence as powerful weight and glucose control drugs, and are used for the treatment of type 2 diabetes (T2D) and obesity. Semaglutide and tirzepatide, currently the most widely used within this class, are both potent molecules, but have a short half-life, requiring weekly administration by subcutaneous injections. Moreover, since their clinical benefits rapidly disappear upon treatment cessation, T2D and obese patients may have a life-long dependency on IRAs, and the requirement for weekly injections can negatively affect the quality of life and the adherence to therapy, as well as create a significant financial burden. Therefore, increasing the interval between injections has become one of the major goals in the field. Here, we present our preclinical studies on the delivery of IRAs with MYO Technology. Animal proof-of-concept studies demonstrate that MYO Technology-delivered IRAs are functional, and efficacious in promoting long-lasting weight and glucose control in mouse models of diet-induced obesity. Moreover, engineering the IRAs to facilitate blood-brain barrier penetration further enhances treatment efficacy, with benefits persisting beyond one year following a single administration. Together, these findings highlight MYO Technologys potential to transform care for patients with T2D and obesity by enabling long-lasting therapeutic effects with minimal dosing, ultimately improving quality of life and treatment adherence.

physiology↗

bioRxiv2023

PET imaging of fibroblast activation protein alpha (FAP) detects incipient cardiotoxicity due to anthracycline chemotherapy

BackgroundAnthracycline chemotherapy is associated with a risk of cardiotoxicity leading to heart disease, particularly in pediatric cancer patients. Gold standard methods of detecting cardiotoxicity are insufficiently sensitive to early damage and specific pathophysiologies driving disease. Positron emission tomography (PET) couples anatomical resolution with biochemical mechanistic selectivity and potentially addresses the current diagnostic limitations in cardio-oncology. We aimed to validate PET imaging biomarkers targeting fibroblast activation protein alpha (FAP), Translocator protein (TSPO), and norepinephrine receptor (NET) for detection of incipient anthracycline-induced cardiotoxicity. MethodsCardiotoxicity was established in male C57BL/6J mice by a cumulative dose of 24 mg/kg doxorubicin (DOX) over 2 weeks. DOX mice and their age-matched controls were imaged with echocardiography and PET, using [68Ga]Ga-FAPI-04, [18F]DPA-714, and [18F]MFBG, over 12 weeks. Fractional shortening (FS) was determined from the echocardiograms, and cardiac uptake of the radioligands was quantified from the PET images. Heart sections were collected and used for the analysis of bulk RNA-seq, RT-qPCR, Western blot, in situ hybridization (ISH), and histopathological analysis. ResultsDOX mice exhibited cardiotoxicity and cardiac atrophy. Cardiac [68Ga]Ga-FAPI-04 PET signal was significantly higher in DOX mice from 2 weeks through the study endpoint. By contrast, no cardiac dysfunction was evident by echocardiography until 10 weeks, at which point FS was significantly reduced in DOX mice. There were no differences in [18F]DPA-714 and [18F]MFBG signals. Transcription and translation of FAP, but not TSPO or NET, was detected in cardiomyocytes and were elevated in the DOX hearts, in agreement with the PET data. Genes related to cell adhesion and extracellular remodeling were significantly upregulated in the DOX mice relative to controls. ConclusionsFAP is a sensitive and selective imaging biomarker for incipient cardiotoxicity and FAPI PET is a promising non-invasive imaging tool for identifying patients at risk of cardiotoxicity during or after anthracycline chemotherapy. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC="FIGDIR/small/556130v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@1d9e717org.highwire.dtl.DTLVardef@d2bde8org.highwire.dtl.DTLVardef@1b1f2c5org.highwire.dtl.DTLVardef@1b99bc6_HPS_FORMAT_FIGEXP M_FIG C_FIG NOVELTY AND SIGNIFICANCEO_ST_ABSWhat is Known?C_ST_ABSO_LIAnthracycline chemotherapy results in cardiotoxicity for a sizeable population of treated patients. Cardiotoxocity manifests as cardiac dysfunction, and may result in long-term cardiac disease and heart failure, particularly in survivors of pediatric cancer. C_LIO_LICardiotoxicity is typically defined in terms of left ventricular ejection fraction (LVEF) deficits, as measured by echocardiography. However, this metric is often poorly sensitive to early disease and agnostic to underlying pathophysiology. C_LIO_LIEarly treatment of cardiotoxicity improves recovery and long-term survival, emphasizing the need for accurate diagnostics in incipient disease. C_LI What New Information Does This Article Contain?O_LI[68Ga]Ga-FAPI-04 accumulates in the hearts of mice experiencing doxorubicin-induced cardiotoxicity as a function of fibroblast activation protein alpha (FAP) expression and activity. By contrast, cardiac uptake of radioligands targeting the translocator protein 18-kDa (TSPO) and the norepinephrine transporter (NET) do not differ between DOX animals and controls. C_LIO_LIPositron emission tomography (PET) imaging following administration of [68Ga]Ga-FAPI-04 detects abnormal cardiac remodeling significantly earlier than LVEF decrease is observed, indicating that it may be more sensitive to incipient disease. C_LI Our study identifies fibroblast activation protein alpha (FAP) as a promising diagnostic imaging biomarker in anthracycline-induced cardiotoxicity. We show that cardiac PET signal increases immediately after doxorubicin treatment, and the signal increase is sustained for at least 10 weeks. In addition, we demonstrate that FAP inhibitor (FAPI) PET correlates with expression of FAP protein and gene. Thus, we provide mechanistic insight into potentially-treatable pathophysiologies driving cardiac atrophy and toxicity, and have identified a translational PET tracer that can image the activation of these processes at an early stage.

cancer biology↗

bioRxiv2021

S1P controls endothelial sphingolipid homeostasis via ORMDL

Sphingolipids (SL) are both membrane building blocks and potent signaling molecules regulating a variety of cellular functions in both physiological and pathological conditions. Under normal physiology, sphingolipid levels are tightly regulated, whereas disruption of sphingolipid homeostasis and signaling has been implicated in diabetes, cancer, cardiovascular and autoimmune diseases. Yet, mechanisms governing cellular sensing of SL, and according regulation of their biosynthesis remain largely unknown. In yeast, serine palmitoyltransferase (SPT), catalyzing the first and rate limiting step of sphingolipid de novo biosynthesis, is negatively regulated by Orosomucoid 1 and 2 (Orm) proteins. Lowering sphingolipid levels triggers Orms phosphorylation, resulting in the removal of the inhibitory brake on SPT to enhance sphingolipid de novo biosynthesis. However, mammalian orthologs ORMDLs lack the N-terminus hosting the phosphosites. Thus, which sphingolipid(s) are sensed by the cells, and mechanisms of homeostasis remain largely unknown. This study is aimed at filling this knowledge gap. Here, we identify sphingosine-1-phosphate (S1P) as the key sphingolipid sensed by endothelial cells via S1PRs. The increase of S1P-S1PR signaling stabilizes ORMDLs, which downregulates SPT activity to maintain SL homeostasis. These findings reveal the S1PR/ORMDLs axis as the sensor-effector unit regulating SPT activity accordingly. Mechanistically, the hydroxylation of ORMDLs at Pro137 allows a constitutive degradation of ORMDLs via ubiquitin-proteasome pathway, therefore preserving SPT activity at steady state. The disruption of the S1PR/ORMDL axis results in ceramide accrual, mitochondrial dysfunction, and impaired signal transduction, all leading to endothelial dysfunction, which is an early event in the onset of cardio- and cerebrovascular diseases. The disruption of S1P-ORMDL-SPT signaling may be implicated in the pathogenesis of conditions such as diabetes, cancer, cardiometabolic disorders, and neurodegeneration, all characterized by deranged sphingolipid metabolism. Our discovery may provide the molecular basis for a therapeutic intervention to restore sphingolipid homeostasis.

cell biology↗

bioRxiv2019

Pressure overload leads to coronary plaque formation, progression and myocardial events in ApoE-/- mice

Hypercholesterolemia and hypertension are two major risk factors for coronary artery diseases, which remain the major cause of mortality in the industrialized world. Current animal models of atherosclerosis do not recapitulate coronary plaque disruption, thrombosis and myocardial infarction occurring in human. Recently, we demonstrated that exposure of the heart to high pressure, by transverse aortic constriction (TAC), induced coronary lesions in ApoE-/- mice on chow diet. The aim of this study was to characterize the magnitude and location of coronary lesions in ApoE-/- mice post-TAC, and to assess the susceptibility of coronary plaque to disruption, leading to myocardial events. Here we describe a reliable pathological condition in mice characterized by the development of coronary lesions and its progression leading to myocardial infarction, which better recapitulate human disease. Following TAC surgery, about 90% of ApoE-/- mice develop coronary lesions, especially in the left anterior descending artery, with 59% of the mice manifesting different magnitude of LAD stenosis. Myocardial events, identified in 74% of the mice, were mainly due to coronary plaque thrombosis and occlusion. That TAC induces the development and progression of coronary lesions in ApoE-/- mice leading to myocardial events represents a novel and important tool to investigate the development of coronary lesions and its sequelae in a setting that better resemble human conditions.

pathology↗