Prothymosin Alpha and Immune Responses: Are We Close to Potential Clinical Applications?

Multiomic analyses uncover immunological signatures in acute and chronic coronary syndromes

Acute and chronic coronary syndromes (ACS and CCS) are leading causes of mortality. Inflammation is considered a key pathogenic driver of these diseases, but the underlying immune states and their clinical implications remain poorly understood. Multiomic factor analysis (MOFA) allows unsupervised data exploration across multiple data types, identifying major axes of variation and associating these with underlying molecular processes. We hypothesized that applying MOFA to multiomic data obtained from blood might uncover hidden sources of variance and provide pathophysiological insights linked to clinical needs. Here we compile a longitudinal multiomic dataset of the systemic immune landscape in both ACS and CCS (n = 62 patients in total, n = 15 women and n = 47 men) and validate this in an external cohort (n = 55 patients in total, n = 11 women and n = 44 men). MOFA reveals multicellular immune signatures characterized by distinct monocyte, natural killer and T cell substates and immune-communication pathways that explain a large proportion of inter-patient variance. We also identify specific factors that reflect disease state or associate with treatment outcome in ACS as measured using left ventricular ejection fraction. Hence, this study provides proof-of-concept evidence for the ability of MOFA to uncover multicellular immune programs in cardiovascular disease, opening new directions for mechanistic, biomarker and therapeutic studies.

Programming effects of intrauterine hyperthermia on adrenal gland development

Maternal heat stress during late pregnancy can lead to intrauterine hyperthermia and affect fetal hypothalamic-pituitary-adrenal axis development and function. Herein, we investigated the effects of chronic environmental heat stress exposure of Holstein cows in the last 2 mo of gestation on their offspring's adrenal gland histomorphology and transcriptome. Cows in their last 54 ± 5 d of gestation were either heat-stressed (i.e., housed under the shade of a free stall barn) or provided heat-stress abatement via active cooling (i.e., via water soakers and fans) during a subtropical summer (Temperature-Humidity Index >68). Respiration rate (RR) and skin temperature (ST) were elevated in heat-stressed dams relative to the cows with access to heat abatement (23 bpm and 2 ◦C higher for RR and ST, respectively). Heifers born to heat-stressed cows experienced heat stress in utero (HS), while heifers born to actively cooled cows did not (CL). The adrenal gland was harvested from 6 heifers per group that were euthanized at birth (d 0; n = 12) or one week after weaning (d 63; n = 12). Circulating cortisol was measured from blood samples collected weekly throughout the pre-weaning period. At d 63, heifers that experienced HS while developing in utero had heavier adrenal glands, with a greater total tissue surface area and thickness of the zona glomerulosa (ZG), fasciculata (ZF), and reticularis (ZR), compared with CL heifers. In addition, the adrenal gland of in utero HS heifers had less cells in the ZG, more and larger cells in the ZF and larger cells in the ZR, relative to CL heifers. Although no changes in circulating cortisol were observed through the pre-weaning period, the transcriptomic profile of the adrenal tissue was altered by fetal exposure to hyperthermia. Both at birth and on d 63, approximately 30 pathways were differentially expressed in the adrenal glands of in utero HS heifers relative to CL. These pathways were associated with immune function, inflammation, prolactin signaling, cell function, and calcium transport. Upstream regulators significantly activated or inhibited in the adrenal glands of heifers exposed to intrauterine hyperthermia were identified. Maternal exposure to heat stress during late gestation caused an enlargement of their offspring's adrenal glands by inducing ZG and ZF cell hypertrophy, and caused gene expression changes. These phenotypic, histological, and molecular changes in the adrenal gland might lead to alterations in stress, immune, and metabolic responses later in life.

6-Formylindolo[3,2-b]carbazole, a potent ligand for the aryl hydrocarbon receptor, attenuates concanavalin-induced hepatitis by limiting T-cell activation and infiltration of proinflammatory CD11b+ Kupffer cells

FICZ (6-formylindolo[3,2-b]carbazole) is a potent aryl hydrocarbon receptor agonist that has a poorly understood function in the regulation of inflammation. In this study, we investigated the effect of aryl hydrocarbon receptor activation by FICZ in a murine model of autoimmune hepatitis induced by concanavalin A. High-throughput sequencing techniques such as single-cell RNA sequencing and assay for transposase accessible chromatin sequencing were used to explore the mechanisms through which FICZ induces its effects. FICZ treatment attenuated concanavalin A-induced hepatitis, evidenced by decreased T-cell infiltration, decreased circulating alanine transaminase levels, and suppression of proinflammatory cytokines. Concanavalin A revealed an increase in natural killer T cells, T cells, and mature B cells upon concanavalin A injection while FICZ treatment reversed the presence of these subsets. Surprisingly, concanavalin A depleted a subset of CD55+ B cells, while FICZ partially protected this subset. The immune cells showed significant dysregulation in the gene expression profiles, including diverse expression of migratory markers such as CCL4, CCL5, and CXCL2 and critical regulatory markers such as Junb. Assay for transposase accessible chromatin sequencing showed more accessible chromatin in the CD3e promoter in the concanavalin A-only group as compared to the naive and concanavalin A-exposed, FICZ-treated group. While there was overall more accessible chromatin of the Adgre1 (F4/80) promoter in the FICZ-treated group, we observed less open chromatin in the Itgam (CD11b) promoter in Kupffer cells, supporting the ability of FICZ to reduce the infiltration of proinflammatory cytokine producing CD11b+ Kupffer cells. Taken together, these data demonstrate that aryl hydrocarbon receptor activation by FICZ suppresses liver injury through the limitation of CD3+ T-cell activation and CD11b+ Kupffer cell infiltration.

Linking Gene Fusions to Bone Marrow Failure and Malignant Transformation in Dyskeratosis Congenita

Dyskeratosis Congenita (DC) is a multisystem disorder intrinsically associated with telomere dysfunction, leading to bone marrow failure (BMF). Although the pathology of DC is largely driven by mutations in telomere-associated genes, the implications of gene fusions, which emerge due to telomere-induced genomic instability, remain unexplored. We meticulously analyzed gene fusions in RNA-Seq data from DC patients to provide deeper insights into DC's progression. The most significant DC-specific gene fusions were subsequently put through in silico assessments to ascertain biophysical and structural attributes, including charge patterning, inherent disorder, and propensity for self-association. Selected candidates were then analyzed using deep learning-powered structural predictions and molecular dynamics simulations to gauge their potential for forming higher-order oligomers. Our exploration revealed that genes participating in fusion events play crucial roles in upholding genomic stability, facilitating hematopoiesis, and suppressing tumors. Notably, our analysis spotlighted a particularly disordered polyampholyte fusion protein that exhibits robust higher-order oligomerization dynamics. To conclude, this research underscores the potential significance of several high-confidence gene fusions in the progression of BMF in DC, particularly through the dysregulation of genomic stability, hematopoiesis, and tumor suppression. Additionally, we propose that these fusion proteins might hold a detrimental role, specifically in inducing proteotoxicity-driven hematopoietic disruptions.

Inference of cell type-specific gene regulatory networks on cell lineages from single cell omic datasets

Cell type-specific gene expression patterns are outputs of transcriptional gene regulatory networks (GRNs) that connect transcription factors and signaling proteins to target genes. Single-cell technologies such as single cell RNA-sequencing (scRNA-seq) and single cell Assay for Transposase-Accessible Chromatin using sequencing (scATAC-seq), can examine cell-type specific gene regulation at unprecedented detail. However, current approaches to infer cell type-specific GRNs are limited in their ability to integrate scRNA-seq and scATAC-seq measurements and to model network dynamics on a cell lineage. To address this challenge, we have developed single-cell Multi-Task Network Inference (scMTNI), a multi-task learning framework to infer the GRN for each cell type on a lineage from scRNA-seq and scATAC-seq data. Using simulated and real datasets, we show that scMTNI is a broadly applicable framework for linear and branching lineages that accurately infers GRN dynamics and identifies key regulators of fate transitions for diverse processes such as cellular reprogramming and differentiation.

Proteomic Analysis Identifies Molecular Players and Biological Processes Specific to SARS-CoV-2 Exposure in Endothelial Cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for the severe pandemic of acute respiratory disease, coronavirus disease 2019 (COVID-19), experienced in the 21st century. The clinical manifestations range from mild symptoms to abnormal blood coagulation and severe respiratory failure. In severe cases, COVID-19 manifests as a thromboinflammatory disease. Damage to the vascular compartment caused by SARS-CoV-2 has been linked to thrombosis, triggered by an enhanced immune response. The molecular mechanisms underlying endothelial activation have not been fully elucidated. We aimed to identify the proteins correlated to the molecular response of human umbilical vein endothelial cells (HUVECs) after exposure to SARS-CoV-2, which might help to unravel the molecular mechanisms of endothelium activation in COVID-19. In this direction, we exposed HUVECs to SARS-CoV-2 and analyzed the expression of specific cellular receptors, and changes in the proteome of HUVECs at different time points. We identified that HUVECs exhibit non-productive infection without cytopathic effects, in addition to the lack of expression of specific cell receptors known to be essential for SARS-CoV-2 entry into cells. We highlighted the enrichment of the protein SUMOylation pathway and the increase in SUMO2, which was confirmed by orthogonal assays. In conclusion, proteomic analysis revealed that the exposure to SARS-CoV-2 induced oxidative stress and changes in protein abundance and pathways enrichment that resembled endothelial dysfunction.

Self-assembly of globular proteins with intrinsically disordered protein polyelectrolytes and block copolymers

Intrinsically disordered polypeptides are a versatile class of materials, combining the biocompatibility of peptides with the disordered structure and diverse phase behaviors of synthetic polymers. Synthetic polyelectrolytes are capable of complex phase behavior when mixed with oppositely charged polyelectrolytes, facilitating nanoparticle formation and bulk phase separation. However, there has been limited exploration of intrinsically disordered protein polyelectrolytes as potential bio-based replacements for synthetic polyelectrolytes. Here, we produce negatively charged, intrinsically disordered polypeptides, capable of high-yield expression in E. coli and use this intrinsically disordered peptide to produce entirely protein-based polyelectrolyte complexes. The complexes display rich phase behavior, showing sensitivity to charge density, salt concentration, temperature, and charge fraction. We characterize this behavior through a combination of turbidity assays, dynamic light scattering, and transmission electron microscopy. The robust expression profile and stimuli-responsive phase behavior of the intrinsically disordered peptides demonstrates their potential as easily producible, biocompatible substitutes for synthetic polyelectrolytes.

Immunogenic Cell Death, DAMPs and Prothymosin α as a Putative Anticancer Immune Response Biomarker

The new and increasingly studied concept of immunogenic cell death (ICD) revealed a previously unknown perspective of the various regulated cell death (RCD) modalities, elucidating their immunogenic properties and rendering obsolete the notion that immune stimulation is solely the outcome of necrosis. A distinct characteristic of ICD is the release of danger-associated molecular patterns (DAMPs) by dying and/or dead cells. Thus, several members of the DAMP family, such as the well-characterized heat shock proteins (HSPs) HSP70 and HSP90, the high-mobility group box 1 protein and calreticulin, and the thymic polypeptide prothymosin α (proTα) and its immunoreactive fragment proTα(100–109), are being studied as potential diagnostic tools and/or possible therapeutic agents. Here, we present the basic aspects and mechanisms of both ICD and other immunogenic RCD forms; denote the role of DAMPs in ICD; and further exploit the relevance of human proTα and proTα(100–109) in ICD, highlighting their possible clinical applications. Furthermore, we present the preliminary results of our in vitro studies, which show a direct correlation between the concentration of proTα/proTα(100–109) and the levels of cancer cell apoptosis, induced by anticancer agents and γ-radiation.

Prothymosin Alpha: A Novel Contributor to Estradiol Receptor Alpha-Mediated CD8+ T-Cell Pathogenic Responses and Recognition of Type 1 Collagen in Rheumatic Heart Valve Disease

BACKGROUND

Rheumatic heart valve disease (RHVD) is a leading cause of cardiovascular death in low- and middle-income countries and affects predominantly women. The underlying mechanisms of chronic valvular damage remain unexplored and regulators of sex predisposition are unknown.

METHODS

Proteomics analysis of human heart valves (nondiseased aortic valves, nondiseased mitral valves [NDMVs], valves from patients with rheumatic aortic valve disease, and valves from patients with rheumatic mitral valve disease; n=30) followed by system biology analysis identified ProTα (prothymosin alpha) as a protein associated with RHVD. Histology, multiparameter flow cytometry, and enzyme-linked immunosorbent assay confirmed the expression of ProTα. In vitro experiments using peripheral mononuclear cells and valvular interstitial cells were performed using multiparameter flow cytometry and quantitative polymerase chain reaction. In silico analysis of the RHVD and Streptococcuspyogenes proteomes were used to identify mimic epitopes.

RESULTS

A comparison of NDMV and nondiseased aortic valve proteomes established the baseline differences between nondiseased aortic and mitral valves. Thirteen unique proteins were enriched in NDMVs. Comparison of NDMVs versus valves from patients with rheumatic mitral valve disease and nondiseased aortic valves versus valves from patients with rheumatic aortic valve disease identified 213 proteins enriched in rheumatic valves. The expression of the 13 NDMV-enriched proteins was evaluated across the 213 proteins enriched in diseased valves, resulting in the discovery of ProTα common to valves from patients with rheumatic mitral valve disease and valves from patients with rheumatic aortic valve disease. ProTα plasma levels were significantly higher in patients with RHVD than in healthy individuals. Immunoreactive ProTα colocalized with CD8⁺ T cells in RHVD. Expression of ProTα and estrogen receptor alpha correlated strongly in circulating CD8⁺ T cells from patients with RHVD. Recombinant ProTα induced expression of the lytic proteins perforin and granzyme B by CD8⁺ T cells as well as higher estrogen receptor alpha expression. In addition, recombinant ProTα increased human leukocyte antigen class I levels in valvular interstitial cells. Treatment of CD8⁺ T cells with specific estrogen receptor alpha antagonist reduced the cytotoxic potential promoted by ProTα. In silico analysis of RHVD and Spyogenes proteomes revealed molecular mimicry between human type 1 collagen epitope and bacterial collagen-like protein, which induced CD8⁺ T-cell activation in vitro.

CONCLUSIONS

ProTα-dependent CD8⁺ T-cell cytotoxicity was associated with estrogen receptor alpha activity, implicating ProTα as a potential regulator of sex predisposition in RHVD. ProTα facilitated recognition of type 1 collagen mimic epitopes by CD8⁺ T cells, suggesting mechanisms provoking autoimmunity.

Proteomic profiling reveals engineered chitosan nanoparticles mediated cellular crosstalk and immunomodulation for therapeutic application in apical periodontitis

Macrophages (MQ) are major constituents of chronically inflamed periapical tissues in apical periodontitis. This study aimed to investigate the immunomodulatory effect of engineered bioactive chitosan-based nanoparticles (CSnp) antibiofilm medication on MQ cocultured with periodontal ligament fibroblasts (PdLF). Cells viability, spreading, PdLF migration, and intracellular CSnp uptake were characterized. Tandem Mass Tag-based proteomics was applied to analyze MQ global protein expression profiles after interaction with Enterococcus faecalis biofilm, CSnp-treated biofilm, and CSnp. Secreted inflammatory mediators were analyzed. Following bioinformatics analyses, candidate proteins were validated via targeted proteomics. CSnp maintained cells viability, increased MQ spreading, and PdLF migration (p < 0.05). Transmission electron micrographs demonstrated CSnp internalization via macropinocytosis, clathrin-mediated endocytosis, and phagocytosis. Proteomic analysis revealed that CSnp-treated biofilm upregulated proteins (>1.5-folds, p < 0.05) showed functional enrichment in the pathway of metal sequestration by antimicrobial proteins, while downregulated proteins showed enrichment in ferroptosis. CSnp upregulated proteins exhibiting antioxidant and immunoregulatory properties. Upregulation of SERPINB1 by CSnp (>1.5-folds, p < 0.05) was validated. CSnp-treated biofilm reduced pro-inflammatory IL-1β and nitric oxide but enhanced anti-inflammatory IL-10 and TGF-β1 (p < 0.05). Internalized engineered bioactive CSnp reprogrammed MQ proteomic and cytokine profiles to modulate biofilm-mediated inflammation, and prompted PdLF migration, emphasizing its potential to regulate healing process in the treatment of apical periodontitis.

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CSnp internalized via macropinocytosis, clathrin-mediated endocytosis, and phagocytosis.

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Enterococcus faecalis biofilm altered macrophage proteomic profile.

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Macrophage proteome upon CSnp-treated biofilm interaction was distinct from biofilm.

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CSnp upregulated proteins with immunoregulatory and antioxidant activities.

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CSnp reduced proinflammatory but increased anti-inflammatory mediators.

Proteomics and Organoid Culture Reveal the Underlying Pathogenesis of Hashimoto's Thyroiditis

Hashimoto’s thyroiditis (HT) is an autoimmune disease, and its incidence continues to rise. Although scientists have studied this disease for many years and discovered the potential effects of various proteins in it, the specific pathogenesis is still not fully comprehended. To understand HT and translate this knowledge to clinical applications, we took the mass spectrometric analysis on thyroid tissue fine-needle puncture from HT patients and healthy people in an attempt to make a further understanding of the pathogenesis of HT. A total of 44 proteins with differential expression were identified in HT patients, and these proteins play vital roles in cell adhesion, cell metabolism, and thyroxine synthesis. Combining patient clinical trial sample information, we further compared the transient changes of gene expression regulation in HT and papillary thyroid carcinoma (PTC) samples. More importantly, we developed patient-derived HT and PTC organoids as a promising new preclinical model to verify these potential markers. Our data revealed a marked characteristic of HT organoid in upregulating chemokines that include C-C motif chemokine ligand (CCL) 2 and CCL3, which play a key role in the pathogenesis of HT. Overall, our research has enriched everyone’s understanding of the pathogenesis of HT and provides a certain reference for the treatment of the disease.

Thymus Gland: A Double Edge Sword for Coronaviruses

The thymus is the main lymphoid organ that regulates the immune and endocrine systems by controlling thymic cell proliferation and differentiation. The gland is a primary lymphoid organ responsible for generating mature T cells into CD4+ or CD8+ single-positive (SP) T cells, contributing to cellular immunity. Regarding humoral immunity, the thymic plasma cells almost exclusively secrete IgG1 and IgG3, the two main complement-fixing effector IgG subclasses. Deformity in the thymus can lead to inflammatory diseases. Hassall’s corpuscles’ epithelial lining produces thymic stromal lymphopoietin, which induces differentiation of CDs thymocytes into regulatory T cells within the thymus medulla. Thymic B lymphocytes produce immunoglobulins and immunoregulating hormones, including thymosin. Modulation in T cell and naive T cells decrement due to thymus deformity induce alteration in the secretion of various inflammatory factors, resulting in multiple diseases. Influenza virus activates thymic CD4+ CD8+ thymocytes and a large amount of IFNγ. IFNs limit virus spread, enhance macrophages’ phagocytosis, and promote the natural killer cell restriction activity against infected cells. Th2 lymphocytes-produced cytokine IL-4 can bind to antiviral INFγ, decreasing the cell susceptibility and downregulating viral receptors. COVID-19 epitopes (S, M, and N proteins) with ≥90% identity to the SARS-CoV sequence have been predicted. These epitopes trigger immunity for antibodies production. Boosting the immune system by improving thymus function can be a therapeutic strategy for preventing virus-related diseases. This review aims to summarize the endocrine-immunoregulatory functions of the thymus and the underlying mechanisms in the prevention of COVID-19.

The macrophage-derived protein PTMA induces filamentation of the human fungal pathogen Candida albicans

Evasion of killing by immune cells is crucial for fungal survival in the host. For the human fungal pathogen Candida albicans, internalization by macrophages induces a transition from yeast to filaments that promotes macrophage death and fungal escape. Nutrient deprivation, alkaline pH, and oxidative stress have been implicated as triggers of intraphagosomal filamentation; however, the impact of other host-derived factors remained unknown. Here, we show that lysates prepared from macrophage-like cell lines and primary macrophages robustly induce C. albicans filamentation. Enzymatic treatment of lysate implicates a phosphorylated protein, and bioactivity-guided fractionation coupled to mass spectrometry identifies the immunomodulatory phosphoprotein PTMA as a candidate trigger of C. albicans filamentation. Immunoneutralization of PTMA within lysate abolishes its activity, strongly supporting PTMA as a filament-inducing component of macrophage lysate. Adding to the known repertoire of physical factors, this work implicates a host protein in the induction of C. albicans filamentation within immune cells.

The human fungal pathogen Candida albicans filaments within host macrophages, enabling its escape. Case et al. demonstrate that lysates prepared from macrophage-like cell lines and primary macrophages induce C. albicans filamentation and implicate the immunomodulatory protein prothymosin alpha (PTMA) as a trigger of filamentation produced by host immune cells.

Involvement of SNARE Protein Interaction for Non-classical Release of DAMPs/Alarmins Proteins, Prothymosin Alpha and S100A13

Prothymosin alpha (ProTα) is involved in multiple cellular processes. Upon serum-free stress, ProTα lacking a signal peptide sequence is non-classically released from C6 glioma cells as a complex with Ca²⁺-binding cargo protein S100A13. Thus, ProTα and S100A13 are conceived to be members of damage-associated molecular patterns (DAMPs)/alarmins. However, it remains to be determined whether stress-induced release of ProTα and S100A13 involves SNARE proteins in the mechanisms underlying membrane tethering of the multiprotein complex. In the present study, we used C6 glioma cells as a model of ProTα release. In pull-down assay, p40 synaptotagmin-1 (Syt-1), a vesicular SNARE, formed a hetero-oligomeric complex with homodimeric S100A13 in a Ca²⁺-dependent manner. The interaction between p40 Syt-1 and S100A13 was also Ca²⁺-dependent in surface plasmon resonance (SPR). Immunoprecipitation using conditioned medium (CM) revealed that p40 Syt-1 was co-released with ProTα and S100A13 upon serum-free stress. In in situ proximity ligation assay (PLA), Syt-1 interacted with S100A13 upon serum-free stress in C6 glioma cells. The intracellular delivery of anti-Syt-1 IgG blocked serum free-induced release of ProTα and S100A13. Serum free-induced ProTα-EGFP release was significantly blocked by botulinum neurotoxin/C1 (BoNT/C1), which cleaves target SNARE syntaxin-1 (Stx-1). In immunocytochemistry, the cellular loss of ProTα-EGFP, S100A13, and Syt-1 was also blocked by BoNT/C1. Furthermore, the intracellular delivery of anti-Stx-1 IgG or Stx-1 siRNA treatment blocked Syt-1, S100A13 and ProTα release from C6 glioma cells. All these findings suggest that SNARE proteins play roles in stress-induced non-classical release of DAMPs/alarmins proteins, ProTα and S100A13 from C6 glioma cells.

Protective effect of Tβ4 on central nervous system tissues and its developmental prospects

Tissue repair and regeneration in the central nervous system (CNS) remains a serious medical problem. CNS diseases such as traumatic and neurological brain injuries have a high mortality and disability rate, thereby bringing a considerable amount of economic burden to society and families. How to treat traumatic and neurological brain injuries has always been a serious issue faced by neurosurgeons. The global incidence of traumatic and neurological brain injuries has gradually increased and become a global challenge. Thymosin β4 (Tβ4) is the main G-actin variant molecule in eukaryotic cells. During the development of the CNS, Tβ4 regulates neurogenesis, tangential expansion, tissue growth, and cerebral hemisphere folding. In addition, Tβ4 has anti-apoptotic and anti-inflammatory properties. It promotes angiogenesis, wound healing, stem/progenitor cell differentiation, and other characteristics of cell migration and survival, providing a scientific basis for the repair and regeneration of injured nerve tissue. This review provides evidence to support the role of Tβ4 in the protection and repair of nervous tissue in CNS diseases, especially with the potential to control brain inflammatory processes, and thus open up new therapeutic applications for a series of neurodegenerative diseases.

Beneficial actions of prothymosin alpha-mimetic hexapeptide on central post-stroke pain, reduced social activity, learning-deficit and depression following cerebral ischemia in mice

Prothymosin alpha (ProTα)-mimetic hexapeptide (amino acid: NEVDQE, P6Q) inhibits cerebral or retinal ischemia-induced behavioral, electrophysiological and histological damage. P6Q also abolishes cerebral hemorrhage induced by ischemia with tissue plasminogen activator (tPA). In the present study we examined the beneficial effects of P6Q on other post-stroke prognostic psychology-related symptoms, which obstruct the motivation toward physical therapy. Intravenous (i.v.) administration with tPA (10 mg/kg) at 6 h after photochemically induced thrombosis (PIT) in mice resulted in bilateral central post-stroke pain in thermal and mechanical nociception tests and loss of social activity in the nest building test, both of which were significantly blocked by P6Q (30 mg/kg, i.v.) given at 5 h after PIT. P6Q (30 mg/kg, i.v.) also improved the memory-learning deficit in the step-through test and depression-like behavior in the tail suspension test when it was given 1 day after bilateral common carotid arteries occlusion (BCCAO) in mice. Thus, these studies suggest that P6Q could be a promising candidate to prevent negative prognostic psychological symptoms following focal and global ischemia.

Experimental evidence for the involvement of F0/F1 ATPase and subsequent P2Y12 receptor activation in prothymosin alpha-induced protection of retinal ischemic damage

The inhibition of retinal ischemia-induced damage by post-ischemic prothymosin alpha (ProTα) was not affected in toll-like receptor 4 knockout (TLR4^-/-) mice but blocked by the pretreatment with antibody against F₀/F₁ ATPase α- or β-subunit, novel candidate for ProTα-receptor. In addition to the previous observation of ProTα-induced ATP release from cells, the present study showed a ProTα-induced enhancement of ATP hydrolysis activity of recombinant ATP5A1/5B complex. As the protection of retinal function by post-ischemic ProTα was abolished by anti-P2Y₁₂ antibody, the activation of F₀/F₁ ATPase and subsequent P2Y₁₂ receptor system may play roles in beneficial actions by post-ischemic ProTα.

Antitumor Reactive T-Cell Responses Are Enhanced In Vivo by DAMP Prothymosin Alpha and Its C-Terminal Decapeptide

Prothymosin α (proTα) and its C-terminal decapeptide proTα(100-109) were shown to pleiotropically enhance innate and adaptive immune responses. Their activities have been broadly studied in vitro, focusing primarily on the restoration of the deficient immunoreactivity of cancer patients' leukocytes. Previously, we showed that proTα and proTα(100-109) act as danger-associated molecular patterns (DAMPs), ligate Toll-like receptor-4, signal through TRIF- and MyD88-dependent pathways, promote the maturation of dendritic cells and elicit T-helper type 1 (Th1) immune responses in vitro, leading to the optimal priming of tumor antigen-reactive T-cell functions. Herein, we assessed their activity in a preclinical melanoma model. Immunocompetent mice bearing B16.F1 tumors were treated with two cycles of proTα or proTα(100-109) together with a B16.F1-derived peptide vaccine. Coadministration of proTα or proTα(100-109) and the peptide vaccine suppressed melanoma-cell proliferation, as evidenced by reduced tumor-growth rates. Higher melanoma infiltration by CD3+ T cells was observed, whereas ex vivo analysis of mouse total spleen cells verified the in vivo induction of melanoma-reactive cytotoxic responses. Additionally, increased levels of proinflammatory and Th1-type cytokines were detected in mouse serum. We propose that, in the presence of tumor antigens, DAMPs proTα and proTα(100-109) induce Th1-biased immune responses in vivo. Their adjuvant ability to orchestrate antitumor immunoreactivities can eventually be exploited therapeutically in humans.

Prothymosin alpha and its mimetic hexapeptide improve delayed tissue plasminogen activator-induced brain damage following cerebral ischemia

Tissue plasminogen activator (tPA) administration beyond 4.5 h of stroke symptoms is beneficial for patients but has an increased risk of cerebral hemorrhage. Thus, increasing the therapeutic window of tPA is important for stroke recovery. We previously showed that prothymosin alpha (ProTα) or its mimetic hexapeptide (P6Q) has anti-ischemic activity. Here, we examined the beneficial effects of ProTα or P6Q against delayed tPA-induced brain damage following middle cerebral artery occlusion (MCAO) or photochemically induced thrombosis in mice. Brain hemorrhage was observed by tPA administration during reperfusion at 4.5 and 6 h after MCAO. Co-administration of ProTα with tPA at 4.5 h inhibited hemorrhage and motor dysfunction 2-4 days, but not 7 days after MCAO. ProTα administration at 2 and 4.5 h after MCAO significantly inhibited tPA (4.5 h)-induced motor dysfunction and death more than 7 days. Administration of tPA caused the loss of tight junction proteins, zona occulden-1 and occludin, and up-regulation of matrix metalloproteinase-2/9, in a ProTα-reversible manner. P6Q administration abolished tPA (4.5 h)-induced hemorrhage and reversed tPA (6 h)-induced vascular damage and matrix metalloproteinase-2 and 9 up-regulation. Twice administrations of P6Q at 2 h alone and 6 h with tPA significantly improved motor dysfunction more than 7 days. In photochemically induced thrombosis ischemia, similar vascular leakage and neuronal damage (infarction and motor dysfunction) by late tPA (4.5 or 6 h) were also inhibited by P6Q. Thus, these studies suggest that co-administration with ProTα or P6Q would be beneficial to inhibit delayed tPA-induced hemorrhagic mechanisms in acute ischemic stroke.

RNA-Seq-Based Gene Expression Pattern and Morphological Alterations in Chick Thymus during Postnatal Development

The thymus is a lobulated unique lymphoid immune organ that plays a critical role in the selection, development, proliferation, and differentiation of T cells. The thymus of developing chickens undergoes continued morphological alterations; however, the biomolecular and transcriptional dynamics of the postnatal thymus in avian species is not clear yet. Therefore, the thymuses from chickens at different stages of development (at weeks 0, 1, 5, 9, 18, and 27) were used in the present study. The RNA-seq method was used to study the gene expression patterns. On average, 24120819 clean reads were mapped, differentially expressed genes (DEGs) were identified on the basis of log values (fold change), including 744 upregulated and 425 downregulated genes. The expression pattern revealed by RNA-seq was validated by quantitative real-time PCR (qPCR) analysis of four important genes, which are PCNA, CCNA2, CCNB2, and CDK1. Thus, the current study revealed that during postnatal development, the thymus undergoes severe atrophy. Thymus structure was damaged and gene expression changed dramatically, especially at the 27^th week of age. Moreover, we found significant changes of several signaling pathways such as the cytokine-cytokine receptor interaction and cell cycle signaling pathways. Hence, it may be inferred that those signaling pathways might be closely related to the postnatal chicken thymus development.

Thymosins in multiple sclerosis and its experimental models: moving from basic to clinical application

BACKGROUND

Multiple sclerosis (MS) afflicts more than 2.5 million individuals worldwide and this number is increasing over time. Within the past years, a great number of disease-modifying treatments have emerged; however, efficacious treatments and a cure for MS await discovery. Thymosins, soluble hormone-like peptides produced by the thymus gland, can mediate immune and non-immune physiological processes and have gained interest in recent years as therapeutics in inflammatory and autoimmune diseases.

METHODS

Pubmed was searched with no time constraints for articles using a combination of the keywords "thymosin/s" or "thymus factor/s" AND "multiple sclerosis", mesh terms with no language restriction.

RESULTS

Here, we review the state-of-the-art on the effects of thymosins on MS and its experimental models. In particular, we describe what is known in this field on the roles of thymosin-α1 (Tα1) and -β4 (Tβ4) as potential anti-inflammatory as well as neuroprotective and remyelinating molecules and their mechanisms of action.

CONCLUSION

Based on the data that Tα1 and Tβ4 act as anti-inflammatory molecules and as inducers of myelin repair and neuronal protection, respectively, a possible therapeutic application in MS for Tα1 and Tβ4 alone or combined with other approved drugs may be envisaged. This approach is reasonable in light of the current clinical usage of Tα1 and data demonstrating the safety, tolerability and efficacy of Tβ4 in clinical practice.

Ecto-F0/F1 ATPase as a novel candidate of prothymosin α receptor

OBJECTIVES

Prothymosin α (ProTα) was reported to inhibit the neuronal necrosis by facilitating the plasma membrane localization of endocytosed glucose transporter 1/4 through an activation of putative G_i-coupled receptor. The present study aims to identify a novel ProTα target, which may lead to an activation of G_i-coupled receptor.

METHODS

We used G_i-rich lipid rafts fraction of retinal cell line N18-RE-105 cells for affinity cross-linking. The biological confirmation that F₀/F₁ ATPase is a target protein complex was performed by cell-free experiments using ELISA-based binding assay, surface plasmon resonance assay and quartz crystal microbalance assay, and cell-based experiments to measure extracellular ATP level in the HUVECs culture.

RESULTS

From the cross-linking study and above-mentioned protein-protein interaction assays, ATP5A1 and ATP5B, F₁ ATPase subunits were found to ProTα binding target proteins. In the culture of HUVEC cells, furthermore, ProTα increased the extracellular ATP levels in a reversible manner by anti-ATP5A1- and ATP5B-antibodies.

CONCLUSION

The present study suggests that ProTα may activate ecto-F₀/F₁ ATPase and produced ATP. This study leads to next subjects whether produced ATP and its metabolites, ADP or adenosine may activate corresponding G_i-coupled receptors.

A fragment of the alarmin prothymosin α as a novel biomarker in murine models of bacteria-induced sepsis

Sepsis is a life-threatening condition that requires urgent care. Thus, the identification of specific and sensitive biomarkers for its early diagnosis and management are of clinical importance. The alarmin prothymosin alpha (proTα) and its decapeptide proTα(100-109) are immunostimulatory peptides related to cell death. In this study, we generated bacterial models of sepsis in mice using two Klebsiella pneumoniae strains (L-78 and ATCC 43816) and monitored sepsis progression using proTα(100-109) as a biomarker. Serum concentration of proTα(100-109) gradually increased as sepsis progressed in mice infected with L-78, a strain which, unlike ATCC 43816, was phagocytosed by monocytes/macrophages. Analysis of splenocytes from L-78-infected animals revealed that post-infection spleen monocytes/macrophages were gradually driven to caspase-3-mediated apoptosis. These results were verified in vitro in L-78-infected human monocytes/macrophages. Efficient phagocytosis of L-78 by monocytes stimulated their apoptosis and the concentration of proTα(100-109) in culture supernatants increased. Human macrophages strongly phagocytosed L-78, but resisted cell death. This is the first report suggesting that high levels of proTα(100-109) correlate, both in vitro and in vivo, with increased percentages of cell apoptosis. Moreover, we showed that low levels of proTα(100-109) early post-infection likely correlate with sepsis resolution and thus, the decapeptide could eventually serve as an early surrogate biomarker for predicting bacteria-induced sepsis outcome.

Acute Thymic Involution and Mechanisms for Recovery

Acute thymic involution (ATI) is usually regarded as a virulence trait. It is caused by several infectious agents (bacteria, viruses, parasites, fungi) and other factors, including stress, pregnancy, malnutrition and chemotherapy. However, the complex mechanisms that operate during ATI differ substantially from each other depending on the causative agent. For instance, a transient reduction in the size and weight of the thymus and depletion of populations of T cell subsets are hallmarks of ATI in many cases, whereas severe disruption of the anatomical structure of the organ is also associated with some factors, including fungal, parasitic and viral infections. However, growing evidence shows that ATI may be therapeutically halted or reversed. In this review, we highlight the current progress in this field with respect to numerous pathological factors and discuss the possible mechanisms. Moreover, these new observations also show that ATI can be mechanistically reversed.