Modulation of Alloimmunity by Heat Shock Proteins

Assessment of NLRP3 inflammasome activation in patients with chronic obstructive pulmonary disease before and after lung transplantation

The interplay between purinergic receptors as well as pattern recognition receptors like Toll-like receptors (TLRs) and NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) might have a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of this study was to determine and compare the concentrations of the damage-associated molecular patterns (DAMPs) heat shock protein 70 (Hsp70) and adenosine triphosphate (ATP), and gene expression of their respective receptors as well as NLRP3 inflammasome-related molecules in the peripheral blood of patients with end-stage COPD before and 1 year after lung transplantation (LT). Lung function was assessed by spirometry and diffusion capacity for carbon monoxide (DLCO). Quantitative polymerase chain reaction (qPCR) was applied for detection of TLR2, TLR4, P2X7R, P2Y2R, IL1B, CASP1, and NLRP3 expression. High-sensitivity ELISA kits were used for extracellular (e) Hsp70 and IL-1β, and luminescence assay for eATP measurements. Concentrations of eHsp70 and eATP as well as IL-1β were significantly increased in the plasma of end-stage COPD patients and significantly decreased after LT. In addition, TLR4, P2Y2R, IL1B, CASP1, and NLRP3 expression was up-regulated in COPD patients before LT, while it was significantly suppressed after LT. In conclusion, it could be assumed that NLRP3 inflammasome is activated in the peripheral blood of end-stage COPD patients and that eHsp70 and eATP could be responsible for its activation through triggering their receptors. On the other hand, previously enhanced pro-inflammatory reactions seem to be suppressed to the healthy population levels in lung recipients without allograft rejection.

The influence of the gut-brain axis on anxiety and depression: A review of the literature on the use of probiotics

This review aims to argue how using probiotics can improve anxiety and depressive behaviour without adverse effects, also exploring the impact of postbiotics on it. Specifically, probiotics have drawn more attention as effective alternative treatments, considering the rising cost of antidepressant and anti-anxiety drugs and the high risk of side effects. Depression and anxiety disorders are among the most common mental illnesses in the world's population, characterised by low mood, poor general interest, and cognitive or motor dysfunction. Thus, this study analysed published literature on anxiety, depression, and probiotic supplementation from PubMed and Scopus, focusing on the last twenty years. This study focused on the effect of probiotics on mental health as they have drawn more attention because of their extensive clinical applications and positive impact on various diseases. Numerous studies have demonstrated how the gut microbiota might be critical for mood regulation and how probiotics can affect host health by regulating the gut-brain axis. By comparing the different works analysed, it was possible to identify a strategy by which they are selected and employed and, at the same time, to assess how the effect of probiotics can be optimised using postbiotics, an innovation to improve mental well-being in humans.

Untangling Local Pro-Inflammatory, Reparative, and Regulatory Damage-Associated Molecular-Patterns (DAMPs) Pathways to Improve Transplant Outcomes

Detrimental inflammatory responses after solid organ transplantation are initiated when immune cells sense pathogen-associated molecular patterns (PAMPs) and certain damage-associated molecular patterns (DAMPs) released or exposed during transplant-associated processes, such as ischemia/reperfusion injury (IRI), surgical trauma, and recipient conditioning. These inflammatory responses initiate and propagate anti-alloantigen (AlloAg) responses and targeting DAMPs and PAMPs, or the signaling cascades they activate, reduce alloimmunity, and contribute to improved outcomes after allogeneic solid organ transplantation in experimental studies. However, DAMPs have also been implicated in initiating essential anti-inflammatory and reparative functions of specific immune cells, particularly Treg and macrophages. Interestingly, DAMP signaling is also involved in local and systemic homeostasis. Herein, we describe the emerging literature defining how poor outcomes after transplantation may result, not from just an over-abundance of DAMP-driven inflammation, but instead an inadequate presence of a subset of DAMPs or related molecules needed to repair tissue successfully or re-establish tissue homeostasis. Adverse outcomes may also arise when these homeostatic or reparative signals become dysregulated or hijacked by alloreactive immune cells in transplant niches. A complete understanding of the critical pathways controlling tissue repair and homeostasis, and how alloimmune responses or transplant-related processes disrupt these will lead to new immunotherapeutics that can prevent or reverse the tissue pathology leading to lost grafts due to chronic rejection.

The Complex Molecular Picture of Gut and Oral Microbiota-Brain-Depression System: What We Know and What We Need to Know

Major depressive disorder (MDD) is a complex mental disorder where the neurochemical, neuroendocrine, immune, and metabolic systems are impaired. The microbiota-gut-brain axis is a bidirectional network where the central and enteric nervous systems are linked through the same endocrine, immune, neural, and metabolic routes dysregulated in MDD. Thus, gut-brain axis abnormalities in MDD patients may, at least in part, account for the symptomatic features associated with MDD. Recent investigations have suggested that the oral microbiome also plays a key role in this complex molecular picture of relationships. As on one hand there is a lot of what we know and on the other hand little of what we still need to know, we structured this review focusing, in the first place, on putting all pieces of this complex puzzle together, underlying the endocrine, immune, oxidative stress, neural, microbial neurotransmitters, and metabolites molecular interactions and systems lying at the base of gut microbiota (GM)-brain-depression interphase. Then, we focused on promising but still under-explored areas of research strictly linked to the GM and potentially involved in MDD development: (i) the interconnection of GM with oral microbiome that can influence the neuroinflammation-related processes and (ii) gut phageome (bacteria-infecting viruses). As conclusions and future directions, we discussed potentiality but also pitfalls, roadblocks, and the gaps to be bridged in this exciting field of research. By the development of a broader knowledge of the biology associated with MDD, with the inclusion of the gut/oral microbiome, we can accelerate the growth toward a better global health based on precision medicine.

Enquiring beneath the surface: can a gene expression assay shed light into the heterogeneity among newborns with neonatal encephalopathy?

BACKGROUND

We aimed to assess whether a gene expression assay provided insights for understanding the heterogeneity among newborns affected by neonatal encephalopathy (NE).

METHODS

Analysis by RT-qPCR of the mRNA expression of candidate genes in whole blood from controls (n = 34) and NE (n = 24) patients at <6, 12, 24, 48, 72 and 96 h of life, followed by determination of differences in gene expression between conditions and correlation with clinical variables.

RESULTS

During the first 4 days of life, MMP9, PPARG, IL8, HSPA1A and TLR8 were more expressed and CCR5 less expressed in NE patients compared to controls. MMP9 and PPARG increased and CCR5 decreased in moderate/severe NE patients compared to mild. At 6-12 h of life, increased IL8 correlated with severe NE and death, decreased CCR5 correlated with chorioamnionitis and increased HSPA1A correlated with expanded multiorgan dysfunction, severe NE and female sex.

CONCLUSIONS

MMP9, PPARG and CCR5 mRNA expression within first days of life correlates with the severity of NE. At 6-12 h, IL8 and HSPA1A are good reporters of clinical variables in NE patients. HSPA1A may have a role in the sexual dimorphism observed in NE. CCR5 is potentially involved in the link between severe NE and chorioamnionitis.

Host expression system modulates recombinant Hsp70 activity through post-translational modifications

The use of model organisms for recombinant protein production results in the addition of model-specific post-translational modifications (PTMs) that can affect the structure, charge, and function of the protein. The 70-kDa heat shock proteins (Hsp70) were originally described as intracellular chaperones, with ATPase and foldase activity. More recently, new extracellular activities of Hsp70 proteins (e.g. as immunomodulators) have been identified. While some studies indicate an inflammatory potential for extracellular Hsp70 proteins, others suggest an immunosuppressive activity. We hypothesized that the production of recombinant Hsp70 in different expression systems would result in the addition of different PTMs, perhaps explaining at least some of these opposing immunological outcomes. We produced and purified Mycobacterium tuberculosis DnaK from two different systems, Escherichia coli and Pichia pastoris, and analyzed by mass spectrometry the protein preparations, investigating the impact of PTMs in an in silico and in vitro perspective. The comparisons of DnaK structures in silico highlighted that electrostatic and topographical differences exist that are dependent upon the expression system. Production of DnaK in the eukaryotic system dramatically affected its ATPase activity, and significantly altered its ability to downregulate MHC II and CD86 expression on murine dendritic cells (DCs). Phosphatase treatment of DnaK indicated that some of these differences related specifically to phosphorylation. Altogether, our data indicate that PTMs are an important characteristic of the expression system, with differences that impact interactions of Hsps with their ligands and subsequent functional activities.

Gut Microbiota in Alzheimer's Disease, Depression, and Type 2 Diabetes Mellitus: The Role of Oxidative Stress

Gut microbiota consists of over 100 trillion microorganisms including at least 1000 different species of bacteria and is crucially involved in physiological and pathophysiological processes occurring in the host. An imbalanced gastrointestinal ecosystem (dysbiosis) seems to be a contributor to the development and maintenance of several diseases, such as Alzheimer's disease, depression, and type 2 diabetes mellitus. Interestingly, the three disorders are frequently associated as demonstrated by the high comorbidity rates. In this review, we introduce gut microbiota and its role in both normal and pathological processes; then, we discuss the importance of the gut-brain axis as well as the role of oxidative stress and inflammation as mediators of the pathological processes in which dysbiosis is involved. Specific sections pertain the role of the altered gut microbiota in the pathogenesis of Alzheimer's disease, depression, and type 2 diabetes mellitus. The therapeutic implications of microbiota manipulation are briefly discussed. Finally, a conclusion comments on the possible role of dysbiosis as a common pathogenetic contributor (via oxidative stress and inflammation) shared by the three disorders.

Depression and sterile inflammation: Essential role of danger associated molecular patterns

Stress is a major risk factor for psychiatric disorder including major depressive disorder (MDD) and can induce inflammation, which is known to be dysregulated in depression. Several clinical and pre-clinical studies have demonstrated a strong association between depressive symptoms and the expression of factors that increase inflammation. Conversely, administration of anti-inflammatory agents has been shown to ameliorate depressive symptoms, demonstrating the importance of inflammation as a mediator of depression. Although it is clear that inflammation plays a role in the pathophysiology of depression, the mechanism by which inflammation is activated in mood disorders remains unclear. To address this issue, studies have investigated the role of pattern recognition receptor (PRR) activation in stress-induced inflammation and mood disorders. However, the identification of the endogenous factors, referred to as danger-associated molecular patterns (DAMP) that activate these receptors remains understudied. Here we review the role of DAMPs in depression and highlight the clinical evidence for elevation of DAMP signaling in MDD patients and in pre-clinical animal stress models of depression.

An overview of cytokines and heat shock response in polytraumatized patients

Early after injury, local tissue damage induces a local and systemic inflammatory response that activates the immune system and leads to the development of systemic inflammatory response syndrome (SIRS). This post-traumatic response often results in uncontrolled release of inflammatory mediators and over-activation of the immune system, which occasionally results in multiple organ dysfunction syndrome (MODS). In parallel, a state of immunosuppression develops. This counter-regulating suppression of different cellular and humoral immune functions has been termed "compensatory anti-inflammatory response syndrome (CARS)." Both SIRS and CARS occur simultaneously even in the initial phase after injury. Pro- and anti-inflammatory cytokines have been suggested to play a major role in development of SIRS, although the degree of involvement of the different cytokines is quite disparate. While TNF-α and IL-1β are quite irrelevant for predicting organ dysfunction, IL-6 is the parameter that best predicts mortality. The hyperinflammatory state seems to be the cause of post-traumatic immunosuppression and heat shock proteins (HSPs), which have been proposed as one of the endogenous stimuli for the deterioration of the immune system acting as danger-associated molecular patterns (DAMPs). Extracellular HSPA1A released from injured tissues increase up to ten times immediately after trauma and even more in patients with MODS. It has powerful immune properties that could contribute to post-traumatic immunosuppression through several mechanisms that have been previously described, so HSPs could represent trauma-associated immunomodulatory mediators. For this reason, HSPA1A has been suggested to be a helpful early prognostic biomarker of trauma after severe injury: serial quantification of serum HSPA1A and anti-Hsp70 concentrations in the first hours after trauma is proposed to be used as a predictive biomarker of MODS and immunosuppression development in polytraumatized patients.

Effects of ginsenoside Rb1 on oxidative stress injury in rat spinal cords by regulating the eNOS/Nrf2/HO-1 signaling pathway

The present study aimed to investigate whether ginsenoside Rb1 (G-Rb1) attenuates spinal cord injury-associated oxidative stress in rats by regulating the endothelial nitric oxide synthase eNOS/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase (HO)-1 signaling pathway. Sprague Dawley rats were randomly divided into the sham operation group (S group), spinal cord injury group (SCI group), G-Rb1 treatment group (G-Rb1 group) and SCI+G-Rb1+Inhibitor L-name group (L-name group). The posterior limb function was evaluated via the Basso, Beattie and Bresnahan scoring method. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and glutathione (GSH) in serum were measured by ELISA. The pathological changes in the spinal cord were observed by H&E staining. Reverse transcription-quantitative polymerase chain reaction and western blot analyses were used to detect eNOS, phosphorylated (p)-eNOS, heat shock protein (HSP)90, Nrf2 and NAD(P)H quinone dehydrogenase 1 (Nqo1) at the mRNA and protein level. Immunohistochemistry was used to detect the expression of Nrf2 and p-eNOS. Compared with the S group, the scores of spinal cord function in the SCI group were significantly lower, and the levels of MDA were significantly increased, while the levels of SOD, CAT and GSH protein in spinal cord were significantly decreased (P<0.05). The spinal cord tissue exhibited hemorrhage, neuronal degeneration/necrosis, as well as mononuclear cell and lymphocyte infiltration. The eNOS, HSP90, Nrf2, Nqo1 and HO-1 mRNA levels were decreased (P<0.05). Compared with those in the SCI group, the spinal cord function score in the G-Rb1 group were significantly higher and the serum MDA content was significantly decreased, while the activity of SOD, CAT and GSH was significantly increased (P<0.05). The degeneration/necrosis of spinal cord neurons was attenuated, inflammatory cell infiltration was significantly reduced and the levels of eNOS, HSP90, Nrf2, Nqo1 and HO-1 were significantly upregulated (P<0.05). In the group that was administered the eNOS inhibitor L-name, the levels of eNOS, HSP90, Nrf2, Nqo1 and HO-1 were significantly decreased. In conclusion, G-Rb1 attenuates oxidative stress in injured spinal cords. The mechanism may at least in part involve the eNOS/Nrf2/HO-1 pathway.

Physical Exercise Enhanced Heat Shock Protein 60 Expression and Attenuated Inflammation in the Adipose Tissue of Human Diabetic Obese

Heat shock protein 60 (HSP60) is a key protein in the crosstalk between cellular stress and inflammation. However, the status of HSP60 in diabetes and obesity is unclear. In the present study, we investigated the hypothesis that HSP60 expression levels in the adipose tissue of human obese adults with and without diabetes are different and physical exercise might affect these levels. Subcutaneous adipose tissue (SAT) and blood samples were collected from obese adults with and without diabetes (n = 138 and n = 92, respectively, at baseline; n = 43 for both groups after 3 months of physical exercise). Conventional RT-PCR, immunohistochemistry, immunofluorescence, and ELISA were used to assess the expression and secretion of HSP60. Compared with obese adults without diabetes, HSP60 mRNA and protein levels were decreased in SAT in diabetic obese together with increased inflammatory marker expression and glycemic levels but lower VO2 Max. More interestingly, a 3-month physical exercise differentially affected HSP60 expression and the heat shock response but attenuated inflammation in both groups, as reflected by decreased endogenous levels of IL-6 and TNF-α. Indeed, HSP60 expression levels in SAT were significantly increased by exercise in the diabetes group, whereas they were decreased in the non-diabetes group. These results were further confirmed using immunofluorescence microscopy and anti-HSP60 antibody in SAT. Exercise had only marginal effects on HSP60 secretion and HSP60 autoantibody levels in plasma in both obese with and without diabetes. Physical exercise differentially alleviates cellular stress in obese adults with and without diabetes despite concomitant attenuation of the inflammatory response.