Biology subjects

Caligiuri, G.

Publications and source records attributed to Caligiuri, G..

9 recordsLinked to original sources

bioRxiv2026

Fever-range temperature enhances B cells in vitro but is dispensable for the germinal center in vivo

Fever is a conserved physiological response to immune activation characterized by elevated body temperature. While hyperthermia enhances innate and T cell immunity, its role in shaping the B cell compartment remains poorly defined, despite B cells' role in long-term protection. Understanding how temperature modulates B cell physiology is relevant to vaccine strategies, particularly fever management around immunization. Therefore, we investigated the influence of fever-range thermal changes on humoral immunity. To decipher the direct effects, primary B cells from C57BL/6 mice were stimulated in vitro under mild hyperthermic conditions (~1.5{degrees}C increase). Fever-range temperature enhanced B cell activation, facilitated entry into cell division, and increased antigen presentation to CD4+ T cells, while transcriptomic analysis revealed enrichment of pathways involved in protein synthesis and mitochondrial respiration. To determine whether these intrinsic effects translated into altered humoral immunity in vivo, we developed a novel tunable implant-based system to induce localized, 48-hour hyperthermia around a draining lymph node in awake mice without altering core body temperature. Following subcutaneous NP-OVA/alum immunization, localized hyperthermia localized hyperthermia did not enhance antigen-specific germinal center B cell expansion, antibody titers or IgG affinity on day 9. Moreover, heating during priming did not affect the recall humoral response after a booster on day 21. Thus, fever-range temperature directly modulates murine B cell function in vitro but does not enhance humoral immunity in vivo, indicating that the biological consequences of intrinsic B cell thermosensitivity depend on its integration within the multicellular and inflammatory signals shaping germinal center responses.

immunology↗

bioRxiv2026

Frizzled 6 Drives EMT and Stromal Remodeling Downstream of SP1 in Basal-like Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy, in part due to its rapid progression and early metastasis. To uncover novel drivers of this aggressive behavior, we first analyzed Frizzled receptor expression in human PDAC datasets and identified Frizzled 6 (FZD6) as uniquely predictive of poor clinical outcomes among all ten Frizzled family members. High FZD6 expression correlated with significantly worse overall survival for PDAC patients of any age. Functional studies in human PDAC cell lines showed that FZD6 promotes mesenchymal phenotypes, including enhanced migration and growth in 3D culture, while FZD6 loss induces E-cadherin expression and impairs motility without affecting 2D proliferation. In vivo, conditional epithelial deletion of Fzd6 in KPC mice significantly extended survival, reduced tumor burden and metastasis, and remodeled the tumor microenvironment to suppress stromal activation. Single-cell RNA sequencing analysis of human and mouse PDAC tumors confirms that FZD6 is primarily found within the tumor cells and FZD6-activating, noncanonical Wnt ligands are found to be produced by the cancer-associated fibroblasts surrounding the tumors. Mechanistically, we found that FZD6 is a transcriptional target of specificity protein 1 (SP1), a factor upregulated in mutant p53 contexts and within basal-like PDAC subtypes. SP1 knockdown reduced FZD6 expression and signaling through the PCP pathway. Furthermore, reduced SP1 impaired cell motility. Together this implicates the SP1-Fzd6-Wnt/PCP axis as a key driver of epithelial plasticity and disease progression. These findings suggest that FZD6 is a central effector of mutant p53-driven EMT, and a promising therapeutic target in metastatic PDAC.

cancer biology↗

bioRxiv2024

Inositol-Requiring Enzyme 1 Pathway and Autophagy Drive Sequential Response of Endothelial Cells to Febrile Range Hyperthermia

ContextFever is an evolutionarily conserved and adaptive response during infections. However, prolonged fever has numerous systemic metabolic and functional side effects. In the heart, prolonged fever associated with infection is linked to fatal adverse effects, particularly involving impaired coronary circulation. Yet, the direct relationship between elevated temperature and coronary microcirculation dysfunction, remains to be fully demonstrated. In this study, we aimed to explore the specific responses of human coronary artery endothelial cells (HCAECs) to fever-range hyperthermia. MethodHCAECs were cultured at either 37{degrees}C or 40{degrees}C for up to 24 hours. Transcriptomic and proteomic profiles were obtained through microarray and mass spectrometry after 6, 12, and 24 hours of exposure. Key signaling pathways, upstream regulators, and candidate mechanisms were identified and validated at the mRNA and protein levels using mechanistic approaches. ResultsProlonged hyperthermia compromised HCAEC function, evidenced by cell detachment, loss of junctions, and increased permeability. HCAECs rapidly activated the unfolded protein response (UPR), including IRE1 activation and XBP1 splicing. Additionally, autophagic flux was significantly elevated, participating in the degradation of junction proteins. Pharmacological inhibition of IRE1 reduced the autophagic burden, protected against cell detachment, and preserved junction integrity over time. ConclusionOur findings reveal that in response to fever-range hyperthermia, the IRE1-autophagy axis regulates the survival and function of coronary endothelial cells. This mechanism could play a key role in modulating endothelial responses during infection and contribute to the pathological outcomes of fever. Furthermore, it may be relevant in local inflammatory conditions with elevated temperatures.

cell biology↗

bioRxiv2024

Host response during unresolved urinary tract infection alters mammary tissue homeostasis through collagen deposition and TIMP1

Exposure to pathogens throughout a lifetime influences immunity and organ function. Here, we explored how the systemic host-response to bacterial urinary tract infection (UTI) induces tissue-specific alterations to the mammary gland. Utilizing a combination of histological tissue analysis, single cell RNA sequencing and flow cytometry, we identified that mammary tissue from UTI-bearing mice display collagen deposition, enlarged ductal structures, ductal hyperplasia with atypical epithelial transcriptomes and altered immune composition. Bacterial cells were absent in the mammary tissue and blood of UTI-bearing mice, therefore, alterations to the distal mammary tissue were mediated by the systemic host response to local infection. Furthermore, broad spectrum antibiotic treatment resolved the infection and restored mammary cellular and tissue homeostasis. Systemically, unresolved UTI correlated with increased plasma levels of the metalloproteinase inhibitor, TIMP1, which controls extracellular matrix (ECM) remodeling and neutrophil function. Treatment of nulliparous and post-lactation UTI-bearing female mice with a TIMP1 neutralizing antibody, or broad-spectrum antibiotic, prevented mammary collagen deposition, thus providing evidence for an unexpected link between the systemic host response during UTI and mammary alterations. SummaryThe systemic response during urinary tract infection induces TIMP1-driven collagen deposition specifically into the mammary gland.

developmental biology↗

bioRxiv2023

Camouflaging Endovascular Stents with an Endothelial Coat Using CD31 Domain 1-mimetic Peptides

BackgroundEndovascular stents and flow diverters have become widely used for the treatment of vascular diseases; however, their effectiveness is often limited by the deposition and activation of blood platelets and leukocytes. The foreignness of these devices often triggers pathologic local reactions that impede their integration and compromise their efficacy. In this study, we developed a method to camouflage endovascular stents and flow diverters by coating them with a surface that mimics healthy endothelium, in order to promote more effective device integration and prevent the activation of blood cells. MethodsWe designed peptides using domain 1 and/or domain 2 of human CD31 and synthesized the chosen peptide to coat clinical-grade nitinol flow diverters and cobalt chromium balloon expandable stents. The coated stents were implanted in adult rabbits and included control groups of uncoated devices and drug-eluting CoCr stents. The rabbits were monitored for 60 days, during which we assessed the integration of the devices under a physiologic confluence of endothelial cells. ResultsOur results demonstrated that the stents coated with the CD31-Domain 1 mimicking peptide promoted a smooth integration of the devices under a physiologic confluence of endothelial cells. By day 7, the coated stents were entirely covered by a smooth endothelium, unlike bare-metal and drug-eluting stents which remained largely exposed to the flowing blood. By day 60, the coated stents demonstrated superiority over both bare-metal and drug-eluting stents, as they resulted in the formation of a "neo-arterial" wall at the entrance of the aneurysmal sac. ConclusionOur method provides a promising step towards the development of more effective and biocompatible endovascular devices. The CD31 domain 1 coating prevented the pathologic local reaction at the site of stent implantation and promoted faster and more effective device integration. Further studies are necessary to investigate the efficacy and safety of CD31 domain 1 coatings on a larger scale, as well as their long-term durability and potential clinical applications.

bioengineering↗

bioRxiv2023

Prolonged body temperature tuning in mice using radio frequency generating electromagnetic resonant circuit-system

RationalIn endothermic animals, body temperature (BT) is an evolutionary conserved and well characterized physical parameter that guarantees physiological functioning state. It results from the sum of bioenergetic processes of the body weighted by behavioral strategies, heat loss, and thermolytic processes. However, the intrinsic impact of temperature and temperature changes on the biology is far less understood. To date, the modification of the environmental temperature has constituted the main lever to evaluate the impact of thermic changes in small animal. However, studying intrinsic effect of temperature remains impossible using conventional laboratory equipment, mainly because hypothalamus instructed with information grabbed from the environmental temperature finely regulates and maintain body temperature around 37{degrees}C. Numerous pharmacological treatments have been used to block these thermoregulatory mechanisms, but confer high toxicity while dysregulating the central nervous responses and can potentially have confounding direct effects on studied peripheral tissues. Alternatively, physical methods using energy irradiation were reported, but they remain expensive and usually involve animal immobilization. We aimed at designing a simple and affordable device to adjust and maintain body temperature on the long course in conscious and free-moving animals. MethodWe developed an electromagnetic LC resonant circuit (ELM circuit) producing a radio frequency signal (64 kHz) inside a copper coil refrigerated with a water circuit. This setting is powered by a simple a 0-48V AC generator, allowing the use of a domestic electrical network. This setting can accommodate metal-free 3D-printed circular cages, where adult mice, previously implanted with thermometric ID transponders, are monitored remotely for intraperitoneal temperature over time. ResultsThe BT of mice placed in the ELM circuit could be regulated in a reproducible fashion. Healthy mice increased their BT from 37 to 39.8{+/-}1{degrees}C, upon power supply ranging from 0 to 48V, respectively. In septic mice developing hypothermia (33{+/-}1 {degrees}C), BT could be either normalized to normothermia (37{degrees}C, 24V), or increased to fever-range hyperthermia (40{degrees}C, 48V) as a function of radiofrequency energy. BT tuning was accurate and stable for at least 12h. Blood count after 6 or 12 hours showed no modifications between groups, cardiomyocyte displayed heat shock response within the first hour in mice exposed to the maximal dose (BT=41{degrees}C). MALDI TOF imaging on brain microsections revealed modifications of the brain proteome, as suggested by differential PKC-theta, and prolactin 7B1 load in heated mice, as compared to controls. ConclusionPrecise body temperature tuning is achievable in small animals, and could be of high interest to understand the impact of temperature in (patho)physiology.

physiology↗

bioRxiv2023

Opposing Strain Directions on Adjacent Left Ventricular Segments Predict Fibrotic Remodeling after Acute Myocardial Infarction

BackgroundDespite similar levels of coronary occlusion and standard of care management, the occurrence of scarring over adaptive heart repair following acute myocardial infarction (AMI) remains unpredictable. Recent studies indicate that mechanical cues may modulate the transcriptional programs involved in tissue repair, possibly explaining why ventricular mechanical dyssynchrony an independent predictor of post-infarction outcome. ObjectiveOur study aimed to investigate the relationship between mechanical cues and the outcome of post-myocardial infarction heart remodeling by live imaging. Specifically, we examined the impact of individual variability of myocardial dyssynchrony, characterized by a divergent direction of injured left ventricle wall movement next to live tissue, on the formation of a large scar, dilation of the left ventricle, and loss of pumping function. MethodsWe assessed the location and degree of regional systolic and diastolic dyssynchrony using transthoracic echocardiography coupled with speckle tracking imaging. Specifically, we measured the difference in absolute strain values between adjacent regions of the left ventricle at 5 days following the induction of a standard experimental infarction in female C57Bl6 mice. Three weeks later, transthoracic echocardiography was repeated to analyze the mass and global function of the left ventricle right before termination. We then examined the size of the scar in matched mid-sections of the left ventricle circumferential segments from each mouse using histomorphometry. Finally, we evaluated the potential impact on transcriptional tissue repair programs using spatial transcriptomic analysis on representative hearts with either adaptive or fibrotic post-infarction heart remodeling. ResultsWe analyzed all 96 systolic and diastolic strain-related parameters in the same 48 regions of the left ventricle in all mice, with echocardiographic and histological sections following the same orientation. Stepwise analysis of the live imaging data revealed that a combination of 8 regional strain parameters could predict fibrotic remodeling (Area under the ROC curve= 0.8290). We observed that scarring remodeling was associated with opposing trends of systolic and diastolic circumferential strain % delta values on adjacent regions at day 5, while adaptive remodeling at day 28 occurred when the trend followed the direction of control (sham) hearts. Cluster analysis of gene transcripts and speckle tracking assessment on representative hearts with adaptive or fibrotic post-infarction remodeling indicated a correlation between regional post-infarction dyssynchrony and the transcriptional program. Adrenergic receptors, including Adra1, Trpc3, and Myh7, were found to be linked to specific regional dyssynchrony values and scarring remodeling. ConclusionOur study demonstrates the potential of regional strain parameters obtained through live imaging in predicting fibrotic remodeling following myocardial infarction. Furthermore, our findings suggest a link between regional post-infarction dyssynchrony and the transcriptional program. These results highlight the potential applicability of our approach in clinical settings and provide insights for future personalization of therapeutic strategies.

physiology↗

bioRxiv2022

Development of a clot-adhesive coating to improve the performance of thrombectomy devices

BackgroundThe first-pass complete recanalization by mechanical thrombectomy (MT) for the treatment of stroke remains limited due to the poor integration of the clot within current devices. Aspiration can help retrieval of the main clot but fails to prevent secondary embolism in the distal arterial territory. The dense meshes of extracellular DNA, recently described in stroke-related clots, might serve as an anchoring platform for MT devices. ObjectiveEvaluate the potential of DNA reacting surface to aid the retention of the main clot as well as of its small fragments within the thrombectomy device and improve the potential of MT procedures. MethodsDevice-suitable alloy experimental samples were coated with 15 different compounds and contacted with extracellular DNA or with human peripheral whole blood, to compare their binding to DNA versus flowing blood elements, in vitro. Clinical-grade MT devices were coated with two selected compounds and evaluated in functional bench tests aiming to studying clot retrieval and distal emboli release, concomitant with contact aspiration, using an M1 occlusion model. ResultsBinding properties of samples coated with all compounds were increased for DNA ({approx} 3-fold) and decreased ({approx} 5-fold) for blood elements, essentially platelet, as compared to the bare alloy samples, in vitro. Functional testing showed that surface modification with DNA-binding compounds improved clot retrieval and significantly reduced secondary embolism during experimental recanalization of occluded artery 3D model by thrombectomy procedures. ConclusionOur results suggest that device coating with DNA-binding compounds can considerably improve the outcome of MT procedures in stroke patients. What is already known on this topic - New mechanical thrombectomy device are being improved on the conformation and shape to increase the interaction clot on the physical point of view. However, none interact specifically with the structure or composition of the clot. What this study adds - The design of a chemical surface modification of the device opens the way for a specific targeting tool to increase the interaction with the clot on the molecular level. How this study might affect research, practice or policy - This new surface modification, which can be applied to all commercially available mechanical thrombectomy devices, leads to a decrease in secondary embolization which cannot and is not monitored during the procedure and responsible for new territory damage.

bioengineering↗

bioRxiv2022

Involvement of an IgE/Mast cell/B cell amplification loop in abdominal aortic aneurysm progression

AimsIgE type immunoglobulins and their specific effector cells, mast cells (MCs), are associated with abdominal aortic aneurysm (AAA) progression. In parallel, immunoglobulin-producing B cells, organised in tertiary lymphoid organs (TLOs) within the aortic wall, have also been linked to aneurysmal progression. We aimed at investigating the potential role and mechanism linking local MCs, TLO B cells, and IgE production in aneurysmal progression. Methods and ResultsThrough histological assays conducted on human surgical samples from AAA patients, we uncovered that activated MCs were enriched at sites of unhealed haematomas, due to subclinical aortic wall fissuring, in close proximity to adventitial IgE+ TLO B cells. Remarkably, in vitro the IgEs deriving from these samples enhanced MC production of IL-4, a cytokine which favors IgE class-switching and production by B cells. Finally, the role of MCs in aneurysmal progression was further analysed in vivo in ApoE-/- mice subjected to angiotensin II infusion aneurysm model, through MC-specific depletion after the establishment of dissecting aneurysms. MC-specific depletion improved intramural haematoma healing and reduced aneurysmal progression. ConclusionsOur data suggest that MC located close to aortic wall fissures are activated by adventitial TLO B cell-produced IgEs and participate to their own activation by providing support for further IgE synthesis through IL-4 production. By preventing prompt repair of aortic subclinical fissures, such a runaway MC activation loop could precipitate aneurysmal progression, suggesting that MC-targeting treatments may represent an interesting adjunctive therapy for reducing AAA progression.

pathology↗