Although numerous studies have shown that the hypothalamic-pituitary-adrenal axis plays a vital role in the response to environmental stress by mediating the production of a series of hormones, the mechanism underlying these effects has not been elucidated. This study used proteomics techniques to investigate the differentially expressed proteins (DEPs) in the pituitary glands of pigs and to elucidate the potential changes in the immune-neuroendocrine system under heat stress (HS). In total, 2517 peptides corresponding to 205 proteins were detected. A comparison of the expression patterns between HSs and healthy controls revealed 56 DEPs, of which 31 were upregulated and 25 were downregulated. Ingenuity pathway analysis (IPA) was used to reveal the subcellular characteristics, functional pathways, regulatory networks, and upstream regulators of the identified proteins. The results showed that these differentially expressed proteins were involved in intercellular communication, interactions, apoptosis, nervous system development, functions, abnormalities and other functions, and in the regulatory network. Moreover, the upstream regulators of the differentially expressed proteins were mainly transcriptional regulators, hormones, and cytokines. Thus, the functional network and pathway analyses could provide insights into the complexity and dynamics of HS-host interactions and may accelerate our understanding of the mechanisms underlying HS.

The nonalcoholic fatty liver disease (NAFLD), which is closely related to westernized dietary (WD) patterns, displays a rising epidemiological and economic burden. Since there is no pharmacological therapy approved for this disease, mechanistic studies are warranted. In this work, we investigated the action of carnosine (CAR), a natural dipeptide with several protection roles against oxidative stress in the liver of NAFLD rats. NAFLD was induced by WD-rich sugars and fat, verifying the histological evidence of steatosis. As intraperitoneal administration of CAR reversed liver steatosis, the protein profiles of NAFLD liver and CAR NAFLD liver were evaluated by label-free proteomics approach. A total of 2531 proteins were identified and the 230 and 276 were significantly up- and downregulated, respectively, by CAR treatment of NAFLD rats and involved in fundamental pathways such as oxidative stress and lipid metabolism. Perilipin 2 and apolipoprotein E, components of the plasma membrane of vesicle, resulted in highly downregulated in the CAR-treated NAFLD liver. The advanced bioanalytical approach demonstrated the efficacy of CAR in overcoming the main symptoms of NAFLD, ameliorating the steatosis in the liver.

Acute mountain sickness (AMS) is a clinical syndrome of multi-system physiological disorder after acute exposure to low pressure and low oxygen at high altitude. Quantitative proteomics can systematically quantify and describe protein composition and dynamic changes. In recent years, quantitative proteomics has been widely used in the prevention, diagnosis, treatment and pathogenesis of many diseases. This review summarizes the progress of quantitative proteomics techniques and its application in the prevention, diagnosis, treatment of AMS and mechanisms of rapidly acclimatizing to plateau, in order to provide a reference for the pathogenesis, early intervention, clinical treatment and proteomic research of AMS.

This pilot study aimed to use proteomic profiling of sonicate fluid samples to compare host response during Staphylococcus aureus-associated periprosthetic joint infection (PJI) and non-infected arthroplasty failure (NIAF) and identify potential novel biomarkers differentiating the two.
In this pilot study, eight sonicate fluid samples (four from NIAF and four from S. aureus PJI) were studied. Samples were reduced, alkylated, and trypsinized overnight, followed by analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) on a high-resolution Orbitrap Eclipse mass spectrometer. MaxQuant software suite was used for protein identification, filtering, and label-free quantitation.
Principal component analysis of the identified proteins clearly separated S. aureus PJI and NIAF samples. Overall, 810 proteins were identified based on their detection in at least three out of four samples from each group; 35 statistically significant differentially abundant proteins (DAPs) were found (two-sample t-test p-values ≤0.05 and log2 fold-change values ≥2 or ≤-2). Gene ontology pathway analysis found that microbial defense responses, specifically those related to neutrophil activation, to be increased in S. aureus PJI compared to NIAF samples.
Proteomic profiling of sonicate fluid using LC-MS/MS differentiated S. aureus PJI and NIAF in this pilot study. Further work is needed using a larger sample size and including non-S. aureus PJI and a diversty of NIAF-types.

Safflower injection (SI), a water-extract preparation from safflower (Carthamus tinctorius L.), has been widely used for the treatment of cardio-cerebrovascular diseases. This work aims to develop an approach for identifying PK markers of cardiovascular herbal medicines using SI as a case study. Firstly, qualitative and quantitative analyses were performed to reveal ingredients of the preparation via HPLC-MS. Subsequently, multiple PK ingredients and integrated PK investigations were carried out to ascertain ingredients with favorable PK properties (e.g., easily detected at conventional PK time points and high system exposure) for the whole preparation. Next, ingredients against cardiovascular diseases (CVDs) in the preparation were predicted with target fishing and system pharmacology studies. Finally, ingredients with favorable PK properties, satisfactory PK representativeness for the preparation, and high relevance to CVDs were considered as potential PK markers. Their therapeutic effect was further evaluated using the H2O2-induced H9c2 cardiomyocyte-injured model and a proteomics study to identify objective PK markers. As results, it disclosed that SI mainly contains 11 ingredients. Among them, five ingredients, namely, hydroxysafflor yellow A (HSYA), syringin (SYR), p-coumaric acid (p-CA), scutellarin (SCU), and p-hydroxybenzaldehyde (p-HBA), showed favorable PK properties. HSYA, SYR, and rutin (RU) were predicted to show high relevance to CVDs and screened as potential PK markers. However, only HSYA and SYR were confirmed as therapeutic ingredients against CVDs. Combined with these findings, only HSYA demonstrated satisfactory representativeness on PK properties and therapeutic effects of multiple ingredients of the preparation, thereby indicating that HSYA is a potential PK marker for the SI. The results of this study can provide a reference for the characterization of PK markers for traditional Chinese medicines.

Aging is a process that occurs in tissues and across species, leading to the degradation of many biological processes. We previously demonstrated that rabbits are a feasible model for studying aging due to their genetic homology and relatively short lifespan in comparison to humans. We utilized a cPILOT multiplexing strategy to identify proteomic changes in spleen tissues of young, middle, and old aged rabbits. We identified 63 proteins that change significantly (p < 0.05) with age and notably these proteins relate to nucleotide and RNA binding, DNA repair, actin regulation, and immune system pathways. Here, we explore the implications of aging in the spleen and demonstrate the utility of a rabbit model to understand aging processes.

Cyclic adenosine monophosphate (cAMP) signaling activates multiple downstream cellular targets in response to different stimuli. Specific phosphorylation of key target proteins via activation of the cAMP effector protein kinase A (PKA) is achieved via signal compartmentalization. Termination of the cAMP signal is mediated by phosphodiesterases (PDEs), a diverse group of enzymes comprising several families that localize to distinct cellular compartments. By studying the effects of inhibiting individual PDE families on the phosphorylation of specific targets it is possible to gain information on the subcellular spatial organization of this signaling pathway.We describe a phosphoproteomic approach that can detect PDE family-specific phosphorylation changes in cardiac myocytes against a high phosphorylation background. The method combines dimethyl labeling and titanium dioxide-mediated phosphopeptide enrichment, followed by tandem mass spectrometry.

(1) Background: Polycystic liver disease (PLD) is a heterogeneous group of congenital disorders characterized by bile duct dilatation and cyst development derived from cholangiocytes. Nevertheless, the cystogenesis mechanism is currently unknown and the PLD treatment is limited to liver transplantation. Novel and efficient therapeutic approaches are th6us needed. In this context, the present work has a principal aim to find novel molecular pathways, as well as new therapeutic targets, involved in the hepatic cystogenesis process. (2) Methods: Quantitative proteomics based on SWATH-MS technology were performed comparing hepatic proteomes of Wild Type and mutant/polycystic livers in a polycystic kidney disease (PKD) murine model (Pkd1cond/cond;Tam-Cre-/+). (3) Results: We identified several proteins altered in abundance, with two-fold cut-off up-regulation or down-regulation and an adjusted p-value significantly related to hepatic cystogenesis. Then, we performed enrichment and a protein-protein analysis identifying a cluster focused on hepatic fibrinogens. Finally, we validated a selection of targets by RT-qPCR, Western blotting and immunohistochemistry, finding a high correlation with quantitative proteomics data and validating the fibrinogen complex. (4) Conclusions: This work identified a novel molecular pathway in cystic liver disease, highlighting the fibrinogen complex as a possible new therapeutic target for PLD.

The skin is an important barrier against external attacks from bacteria, radicals, or radiations. UV-A radiations cause significant impairment of this barrier, inducing inflammation, oxidative stress, and wrinkle formation, thereby promoting photoaging. Previous studies reported that carnosine, a potent antioxidant, and carbonyl scavenger agent, may prevent photoaging features in the skin of hairless mice exposed to UV-A radiations. In the present study, we used a quantitative proteomic approach to analyze the changes evoked by carnosine in the skin proteome of hairless mice exposed to UV-A. This approach allowed to quantify more than 2480 proteins, among them consistent differences were observed for 89 proteins in UV-A exposed vs control unexposed skins, and 252 proteins in UV-A-exposed skin preventively treated by carnosine (UVAC) vs UV-A. Several functional pathways were altered in the skins of UV-A exposed hairless mice, including the integrin-linked kinase, calcium signaling, fibrogenesis, cell migration and filament formation. An impairment of mitochondrial function and metabolism was observed, with an up-regulation of cytochrome C oxidase 6B1 and NADH: ubiquinone oxidoreductase S8. Skins pre-treated by carnosine were prevented from UV-A induced proteome alterations. In conclusion, our study emphasizes the potency of a proteomic approach to identify the consequences of UV radiations in the skins, and points out the capacity of carnosine to prevent the alterations of skin proteome evoked by UV-A.

Alkyl hydroperoxide reductase (AhP), catalase G (KatG), and catalase E (KatE) are the main enzymes to scavenge the excessive hydrogen peroxide in E. coli. It was found the concentration of endogenous H2O2 was submicromolar in a mutant strain E. coli MG1655/ΔAhpΔKatEΔKatG, which was enough to cause damage to DNA and proteins as well as concomitant cell growth and metabolism. However, few studies explored how submicromolar intracellular hydrogen peroxide alters protein function and regulates the signaling pathways at the proteome level. In order to study the effect of endogenous oxidative stress caused by submicromolar hydrogen peroxide, this study first constructed a mutant strain E. coli MG1655/ΔAhpΔKatEΔKatG. Then, label-free quantitative proteomic analysis was used to quantify the differentially expressed proteins between the wild-type strain and the mutant strain. A total of 265 proteins were observed as differentially expressed proteins including 108 upregulated proteins and 157 downregulated proteins. Among them, three differentially expressed proteins were also validated by parallel reaction monitoring (PRM) methodology. The 265 differentially expressed proteins are not only involved with many metabolism pathways including the TCA cycle, the pentose phosphate pathway, and the glyoxylic acid cycle, but also activated the DNA repair and cellular antioxidant signaling pathway. These findings not only demonstrated that ahp, katE, and katG played the critical role in aerobic growth but also delineated proteins network and pathway regulated by submicromolar intracellular hydrogen peroxide, which allowed a deeper understanding of oxidative signaling in E. coli. The findings of this study also demonstrate that the mutant E. coli may serve as a cell model to investigate the effect of endogenous oxidative stress and downstream signaling pathways. KEY POINTS: • The mutant strain E. coli MG1655/ΔAhpΔKatEΔKatG was constructed to study the effect of endogenous oxidative stress in E. coli. • A total of 265 differentially expressed proteins were quantified and enriched in metabolic pathways and antioxidant systems by using label-free proteomics analysis. • The findings of this study demonstrate that the mutant E. coli may serve as an effective tool to investigate the endogenous oxidative stress.