Dataset Information

Characterization of I-Ab MHCII immunopeptidome eluted from control and obese (Ob/Ob) mice (2)

ABSTRACT: In Dendritic cells (DC), the MHC II eluted immunopeptidome reflects the antigenic composition of the microenvironment. Proteins are transported and processed into peptides in endosomal MHC II compartments through autophagy or phagocytosis; extracellular peptides can also directly bind MHC II proteins at the cell surface. Altogether, these mechanisms allow DC to sample both the intra and extracellular environment. With an increase in mass spectrometry sensitivity and accuracy, we can now finally tackle important questions on the nature and plasticity of the MHC-II immunopeptidome in health and disease. Presented epitopes, neoepitopes, and PTM-modified epitopes can be quantitatively and qualitatively analyzed to provide a comprehensive picture of DC role in immunosurveillance. To determine whether the redox metabolic conditions induce an altered spectrum of presented peptides, we eluted immunoaffinity-purified I-Ab from conventional dendritic cells isolated from control B6 or obese Ob/Ob mice, and analyzed MHC-II-associated peptides by LC/MS/MS using combined data-dependent (DDA) and data-independent acquisition (DIA) approaches. We analyzed the DIA data by employing a reference spectral library consisting of all peptides identified by database matching in the pool of spectra from combined DDA dataset, thus allowing a direct label-free quantitation of relative abundances between the two sample categories. The quantitative analysis of the I-Ab-eluted immunopeptidomes pinpoint important differences in peptide presentation and epitope selection in obese mice.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Spleen, Conventional Dendritic Cell

SUBMITTER: Cristina Clement

LAB HEAD: Laura Santambrogio MD PhD; contact: Cristina C Clement PhD

PROVIDER: PXD018783 | Pride | 2021-03-21

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	022018_BL6_DC_FLT3-t1.mgf	Mgf
	022018_BL6_DC_FLT3-t1.raw	Raw
	022018_BL6_DC_FLT3_t2.mgf	Mgf
	022018_BL6_DC_FLT3_t2.raw	Raw
	022018_BL6_DC_FLT3_t3.mgf	Mgf

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Publications

Pleiotropic consequences of metabolic stress for the major histocompatibility complex class II molecule antigen processing and presentation machinery.

Clement Cristina C CC Nanaware Padma P PP Yamazaki Takahiro T Negroni Maria Pia MP Ramesh Karthik K Morozova Kateryna K Thangaswamy Sangeetha S Graves Austin A Kim Hei Jung HJ Li Tsai Wanxia TW Vigano' Marco M Soni Rajesh K RK Gadina Massimo M Tse Harley Y HY Galluzzi Lorenzo L Roche Paul A PA Denzin Lisa K LK Stern Lawrence J LJ Santambrogio Laura L

Immunity 20210315 4

Hyperglycemia and hyperlipidemia are often observed in individuals with type II diabetes (T2D) and related mouse models. One dysmetabolic biochemical consequence is the non-enzymatic reaction between sugars, lipids, and proteins, favoring protein glycation, glycoxidation, and lipoxidation. Here, we identified oxidative alterations in key components of the major histocompatibility complex (MHC) class II molecule antigen processing and presentation machinery in vivo under conditions of hyperglycem ...[more]

PMID: 33725478

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Project description:Proteomic modifications linked to non-enzymatic glycation and glycoxidation are common in all tissues under hyperglycemic conditions, as present in metabolic syndrome, type 2 diabetes (T2D), mice bearing a homozygous mutation in leptin (so-called Ob/Ob mice, a common model of obesity and T2D) and mice subjected to a high fat diet (HFD). It has been already shown that the circulating levels of glycated or glycoxidated proteins (e.g., glycated hemoglobin or albumin) are commonly employed as a reliable indicator of overall glycemic status. Albeit these initial non-enzymatic reactions are reversible, following a series of chemical rearrangements protein glycation and glycoxidation become irreversible, generating the so-called advanced glycation end-products (AGEs). AGEs are commonly detected in tissue proteins with an extended half-life, including dermal collagens as well as extracellular matrix proteins. In these proteins, Nϵ-carboxymethyllysine (CML), pentosidins, and glucosepane represent the most prevalent AGEs. As an additional, novel mechanism linking protein PTMs to altered immunity, the research presented herein highlights that several components of the MHC class II antigen processing and presentation machinery are glycated in metabolic conditions associated with increased oxidative stress, leading to qualitative and quantitative changes in the MHC class II immunopeptidome. To investigate the impact of T2D and metabolic syndrome on the proteome of antigen presenting cells (APCs) we isolated dendritic cells (DCs, which are key for the initiation of antigen-specific immunity) from the lymph nodes of Ob/Ob mice and syngeneic, age-matched control C57BL/6 (B6) mice and mapped the oxidized proteins at the molecular and cellular level by employing label-free mass spectrometry using at least three biologically independent whole lysates of DCs. Analysis of the type of post-translational modifications (PTMs) accumulated in the proteome from the combined three biological Ob/Ob samples ranked the formyl-lysine and site-specific carboxymethylation on lysine (CML) as the most abundant AGEs found in the glycated proteome; with CML having about two-fold increase in their total PTM-modified spectral counts in the Ob/Ob vs control dendritic cell proteome. Additional glycoxidation-specific PTMs, that mapped only on the Ob/Ob proteome, albeit at a smaller amount than CML and formyl lysine, were glyceryl lysine and 3-deoxyglucosone. Finally, a separate proteomic analysis, performed on gradient purified late endosomes also mapped an increased number of PTM-modified proteins in the Ob/Ob organelles. Ingenuity pathway analysis (IPA) analysis identified metabolic pathways as well as phagocytosis, antigen processing and presentation and phagosome maturation amongst the top pathways including a higher number of proteins modified by AGEs or carbonylation in primary DCs from Ob/Ob vs. control mice. The site-specific amide-AGE modifications that we detected also mapped to proteins involved in response to DC signaling, immune cell trafficking, actin and cytoskeleton signaling, cell movement, and carbohydrate, nucleic acids and protein metabolism. Overall, these findings indicate that the DC proteome of Ob/Ob mice has an increased number of carbonyl PTMs and AGEs as compared to DC of C57BL/6 mice. The results presented herein are one of the first to map the redox mediated PTM in the primary mouse DC in healthy vs T2DM type syndrome physiological conditions.

Project description:In Dendritic cells (DC), the MHC II eluted immunopeptidome reflects the antigenic composition of the microenvironment. Proteins are transported and processed into peptides in endosomal MHC II compartments through autophagy or phagocytosis; extracellular peptides can also directly bind MHC II proteins at the cell surface. Altogether, these mechanisms allow DC to sample both the intra and extracellular environment. To understand the contribution of the lymph proteome to the MHC-II immunopeptidome we eluted I-Ab complexes from DCs harvested from the deep cervical or mesenteric nodes and investigated whether the I-Ab presented peptidome reflects the anatomical distribution of the proteomes carried by the lymph collected from the same anatomical districts. Heatmap representation and cluster analysis indicated differences among the two immunopeptidome. Similarly, regression analysis showed a much higher regression coefficient among MHC II immunopeptidomes eluted from the same anatomical district (r=0.699) as compared to the one eluted from the two different anatomical districts (deep cervical, average r = 0.877 and mesenteric, average r = 0.937). Overall, all analyzed peptides displayed the expected I-Ab binding motives, binding affinity and expected range of peptide length. A combination of data dependent (DDA) and data independent (DIA) analysis indicated that around 36% of the eluted peptides were shared by both the cervical and mesenteric lymph nodes. The rest of the eluted peptides were distinct to each lymph node reflecting the qualitatively different proteome associated with each of the two anatomical districts: peptides unique to the cervical lymph nodes displayed many proteins known to be enriched in brain tissue, whereas those unique to mesenteric lymph nodes were enriched in mesenteric organ proteins. As such, the quantitative analysis of the I-Ab-eluted immunopeptidomes pinpoint important differences in peptide presentation and epitope selection in distinct anatomical districts.

Project description:BACKGOUND: Drinking water can be contaminated with pharmaceuticals. However, it is uncertain whether this contamination can have harmful consequences for the liver, especially in the context of obesity. OBJECTIVES: To determine whether chronic, low dose exposure to pharmaceuticals could have deleterious effects in livers of lean and obese mice. METHODS: Lean and ob/ob male mice (5-week-old) were treated for 4 months with a mixture of 11 drugs (acetaminophen, caffeine, carbamazepine, cotinine, diclofenac, erythromycin, ibuprofen, phenazone, roxithromycin, salicylic acid and sulfamethoxazole) provided in drinking water at a concentration of 1 mg/L (for each drug). At the end of the treatment, investigations were performed in liver and plasma. RESULTS: Some liver and plasma abnormalities were observed in ob/ob mice treated with the cocktail containing 1 mg/L of each drug. For this dosage, a gene expression analysis by microarray showed altered expression of circadian genes (e.g. Bmal1, Dbp, Cry1) in lean and obese mice. RT-qPCR analyses carried out in all groups of animals indicated that expression of 8 different circadian genes was significantly modified in a dose-dependent manner. For some genes, a significant modification was observed for dosages as low as 100-1,000 ng/L. Drug mixture and obesity presented an additive effect on circadian gene expression. These data were confirmed in an independent study performed in female mice. CONCLUSIONS: Chronic, low dose exposure to pharmaceuticals disturbed hepatic expression of circadian genes, especially in obese mice. Because some of the 11 drugs can be found in the drinking water at such concentrations (e.g. acetaminophen, carbamazepine, ibuprofen) our data could be relevant in environmental toxicology, in particular for obese individuals exposed to these contaminants. C57BL/6J lean and ob/ob male mice (5-week-old) were treated for 4 months with a mixture of 11 drugs provided in drinking water at a concentration of 1 mg/L (for each drug). 4 groups were designed: untreated versus treated WT and ob/ob mice (n=6 mice per group).