Biology subjects

Ronchese, F.

Publications and source records attributed to Ronchese, F..

7 recordsLinked to original sources

bioRxiv2026

IL-2- and IL-4-dependent signaling play separate and sequential roles in the differentiation of GATA3-hi TH2 cells in vivo

Naive CD4+ T cells differentiation into T-helper type 2 (TH2) cells requires Interleukin 2 (IL-2) and IL-4-dependent signaling as well as presentation of allergens by dendritic cells (DCs). The role of IL-2 and IL-4 in TH2 differentiation has been mostly studied in vitro, however, these models do not account for the heterogeneity of TH responses and bypass the DC-derived signals that are necessary in vivo. We used cytokine-blocking antibodies and IL-4RKO/IL-4RWT mixed bone marrow chimeras to show that IL-4 signaling was not required for initial upregulation of GATA3 by CD4+ T cells after intradermal immunization, but was necessary for later TH2 cell expansion and further GATA3 upregulation. Single-cell transcriptomics and computational analyses confirmed that IL-4 signaling was not necessary for TH2 identity but promoted TH2 proliferation and expression of a pathogenic signature. Early IL-2 blockade prevented GATA3 upregulation without affecting TH2 proliferation or the differentiation of TH1 and TFH subsets after immunization. Adoptive transfer experiments showed that reduced competition for IL-4 in vivo drove extensive T cell proliferation and preferential expansion of the GATA3hi population. Overall, our results suggest temporally and functionally distinct roles of IL-2 and IL-4 during TH2 differentiation: IL-2 is necessary for GATA3 upregulation, while IL-4 drives subsequent TH2 proliferation and licensing to effector activity. Therefore, IL-2 and IL-4 act in a co-ordinated manner to respectively promote TH2 differentiation, expansion, and effector commitment in the LN.

immunology↗

bioRxiv2024

IFN-I signaling in type 2 conventional dendritic cells supports TH2 and T follicular helper differentiation after allergen immunization

Type 2 dendritic cells (DC2s) are essential for TH2 differentiation, but the signaling pathways involved in allergen sensing, DC activation and instruction of CD4+ T cell priming remain unclear. Previous transcriptomic analyses demonstrated a type-I interferon (IFN-I) signature in skin cDC2s following immunization with non-viable larvae of Nippostrongylus brasiliensis (Nb), house dust mite (HDM), and Schistosoma egg antigen (SEA). Blocking IFN-I signaling with anti-IFNAR1 (aIFNAR1) led to reduced TH2 cytokine responses to these antigens, however, the phenotype of cytokine-producing CD4+ T cells was not further defined. Here we show that conditional loss of IFNAR1 signaling in CD11c+ DCs significantly impaired effector TH2 and TFH CD4+ T cell responses to Nb. In vivo proliferation experiments demonstrated reduced numbers of highly divided CD4+ T cells in IFNAR1{Delta}CD11c mice compared to IFNAR1WT, with the highly divided population comprising both TH2 and TFH. Characterization of the cDC2 compartment by flow cytometry and bulk RNAseq demonstrated lower numbers of Nb+ cDC2s in the skin-draining LN and a reduced expression of Il15 and Il15Ra in IFNAR1{Delta}CD11c mice compared to IFNAR1WT, while expression of costimulatory molecules including CD80, CD86, Cd40 and Pdcd1lg2 (PD-L2) was not impaired. Therefore, IFN-I conditioning of skin cDC2s is necessary for their effective priming of CD4+ T cell responses to allergens, providing evidence for a role of tissue cytokines in driving cDC2 activation in a TH2 context.

immunology↗

bioRxiv2021

Intravenous administration of BCG protects mice against lethal SARS-CoV-2 challenge

Early events in the host response to SARS-CoV-2 are thought to play a major role in determining disease severity. During pulmonary infection, the virus encounters both myeloid and epithelioid lineage cells that can either support or restrict pathogen replication as well as respond with host protective versus detrimental mediators. In addition to providing partial protection against pediatric tuberculosis, vaccination with bacille Calmette-Guerin (BCG) has been reported to confer non-specific resistance to unrelated pulmonary pathogens, a phenomenon attributed to the induction of long-lasting alterations within the myeloid cell compartment. Here we demonstrate that prior intravenous, but not subcutaneous, administration of BCG protects human-ACE2 transgenic mice against lethal challenge with SARS-CoV-2 and results in reduced viral loads in non-transgenic animals infected with an alpha variant. The observed increase in host resistance was associated with reductions in SARS-CoV-2-induced tissue pathology, inflammatory cell recruitment and cytokine production that multivariate analysis revealed to be only partially related to diminished viral load. We propose that this protection stems from BCG-induced alterations in the composition and function of the pulmonary cellular compartment that impact the innate response to the virus and the ensuing immunopathology.

immunology↗

bioRxiv2021

The skin environment controls local dendritic cell differentiation and function through innate IL-13

The signals driving the adaptation of type-2 dendritic cells (DC2s) to diverse peripheral environments are not well understood. We show that the development of CD11blow migratory DC2s, a DC2 population unique to the dermis, requires STAT6- and KLF4-dependent IL-13 signaling, whereas DC2s in lung and small intestine are STAT6-independent. Dermal IL-13 is mostly derived from innate lymphoid cells expressing a resting ICOS+ KLRG1-ST2-phenotype. Analysis of public datasets indicates that human skin DC2s also express an IL-4/IL-13 gene signature compared to blood or spleen, suggesting a similar developmental pathway in mice and humans. In the absence of IL-13 signaling, dermal DC2s are stable in number but remain CD11bhi and show defective activation in response to allergen with diminished ability to support IL-4+ GATA3+ Th development, whereas anti-fungal IL-17+ ROR{gamma}t+ responses are increased. Thus, steady-state IL-13 fosters a non-inflammatory and pro-allergic environment in healthy skin via conditioning of local DC2s.

immunology↗

bioRxiv2020

Fate mapping analysis reveals a novel dermal migratory Langerhans-like cell population

Dendritic cells residing in the skin represent a large family of antigen presenting cells, ranging from long-lived Langerhans cells (LC) in the epidermis to various distinct classical dendritic cell subsets in the dermis. Through genetic fate mapping analysis and single cell RNA sequencing we have identified a novel separate population of LC-independent CD207+CD326+ LClike cells in the dermis that homed at a slow rate to the LNs. These LClike cells were long-lived and radioresistant but, unlike LCs, they were gradually replenished by bone-marrow-derived precursors under steady state. LClike cells together with cDC1s were the main migratory CD207+CD326+ cell fractions present in the LN and not, as currently assumed, LCs, which were barely detectable, if at all. These findings bring new insights into the dynamism of cutaneous dendritic cells and opens novel avenues in the development of treatments to cure inflammatory skin disorders.

immunology↗

bioRxiv2019

A semi-automated technique for adenoma quantification in the ApcMin mouse using FeatureCounter

Colorectal cancer is a major contributor to death and disease worldwide. The ApcMin mouse is a widely used model of intestinal neoplasia, as it carries a mutation also found in human colorectal cancers. However, the method most commonly used to quantify tumour burden in these mice is manual adenoma counting, which is time consuming and poorly suited to standardization across different laboratories. We describe a method to produce suitable photographs of the small intestine, process them with an ImageJ macro, FeatureCounter, which automatically locates image features potentially corresponding to adenomas, and a machine learning pipeline to identify and quantify them. Compared to a manual method, the specificity (or True Negative Rate, TNR) and sensitivity (or True Positive Rate, TPR) of this method in detecting adenomas are similarly high at about 80% and 87%, respectively. Importantly, total adenoma area measures derived from the automatically-called tumours were just as capable of distinguishing high-burden from low-burden mice as those established manually. Overall, our strategy is quicker, helps control experimenter bias and yields a greater wealth of information about each tumour, thus providing a convenient route to getting consistent and reliable results from a study.

cancer biology↗

bioRxiv2019

Single-cell analysis of intestinal immune cells during helminth infection

Single cell isolation from helminth infected intestines has been notoriously difficult, due to the strong anti-parasite type 2 immune responses that drive mucus production, tissue remodeling and immune cell infiltration. Through the systematic optimization of a standard intestinal digestion protocol, we were able to isolate millions of immune cells from heavily infected tissues. Using this protocol, we validated many hallmarks of anti-parasite immunity and analyzed immune cells from the lamina propria and granulomas during helminth development, as well as acute and chronic worm infection.

immunology↗