Thymosin alpha 1: biological activities, applications and genetic engineering production

Efficacy of Shenglin decoction in preventing acute severe lymphocytopenia in patients with non-small cell lung cancer undergoing concurrent chemoradiotherapy: a study protocol for a randomized controlled trial

Background

Definitive concurrent chemoradiotherapy (CCRT) followed by maintenance therapy with immune checkpoint inhibitors offers the best chance of cure for patients with stage III non-small cell lung cancer (NSCLC). A significant challenge in this regimen is the occurrence of acute severe lymphopenia (ASL), which can compromise treatment efficacy. Currently, there are no effective strategies for preventing and treating ASL. Shenglin decoction (SLD), a traditional Chinese herbal medicine formulation, has demonstrated preliminary efficacy in mitigating ASL. However, robust evidence from clinical trials and a clear understanding of its mechanism of action are still needed. This study aims to comprehensively assess the efficacy, safety, and underlying mechanisms of SLD in the prevention of ASL.

Methods

This prospective, dual-center, open-label, randomized controlled trial will enroll 140 stage III NSCLC patients. Participants will be randomly allocated in a 1:1 ratio to a control group or an experimental group. Both groups will undergo definitive CCRT. Alongside the commencement of CCRT, the experimental group will receive an additional oral SLD intervention for a duration of three months. The primary outcome is the incidence rate of ASL, defined as the proportion of patients who experience at least one instance of a total lymphocyte count falling below 0.5 × 10^9 cells/L within 3 months of initiating CCRT treatment. Additionally, 16S rRNA gene sequencing analysis of fecal samples to assess gut microbiota, as well as metabolomic analysis of fecal/blood samples, will be conducted to explore potential mechanisms.

Discussion

This study protocol aims to rigorously evaluate the efficacy and safety of SLD, as well as elucidate its mechanism of action in preventing ASL. Successful outcomes could establish SLD as an evidence-based intervention for ASL prevention in NSCLC patients undergoing CCRT.

Trial Registration

The trial was registered at the Chinese Clinical Trials Registry (ChiCTR2300071788, https://www.chictr.org.cn/).

Single-cell RNA sequencing combined with proteomics of infected macrophages reveals prothymosin-α as a target for treatment of apical periodontitis

INTRODUCTION

Chronic apical periodontitis (CAP) is a common infectious disease of the oral cavity. Immune responses and osteoclastogenesis of monocytes/macrophages play a crucial role in CAP progression, and this study want to clarify role of monocytes/macrophages in CAP, which will contribute to treatment of CAP.

OBJECTIVES

We aim to explore the heterogeneity of monocyte populations in periapical lesion of CAP tissues and healthy control (HC) periodontal tissues by single-cell RNA sequencing (scRNA-seq), search novel targets for alleviating CAP, and further validate it by proteomics and in vitro and in vivo evaluations.

METHODS

ScRNA-seq was used to analyze the heterogeneity of monocyte populations in CAP, and proteomics of THP-1-derived macrophages with porphyromonas gingivalis infection were intersected with the differentially expressed genes (DEGs) of macrophages between CAP and HC tissues. The upregulated PTMA (prothymosin-α) were validated by immunofluorescence staining and quantitative real time polymerase chain reaction. We evaluated the effect of thymosin α1 (an amino-terminal proteolytic cleavage product of PTMA protein) on inflammatory factors and osteoclast differentiation of macrophages infected by P. gingivalis. Furthermore, we constructed mouse and rat mandibular bone lesions caused by apical periodontitis, and estimated treatment of systemic and topical administration of PTMA for CAP. Statistical analyses were performed using GraphPad Prism software (v9.2) RESULTS: Monocytes were divided into seven sub-clusters comprising monocyte-macrophage-osteoclast (MMO) differentiation in CAP. 14 up-regulated and 21 down-regulated genes and proteins were intersected between the DEGs of scRNA-seq data and proteomics, including the high expression of PTMA. Thymosin α1 may decrease several inflammatory cytokine expressions and osteoclastogenesis of THP-1-derived macrophages. Both systemic administration in mice and topical administration in the pulp chamber of rats alleviated periapical lesions.

CONCLUSIONS

PTMA upregulation in CAP moderates the inflammatory response and prevents the osteoclastogenesis of macrophages, which provides a basis for targeted therapeutic strategies for CAP.

The efficacy of thymosin alpha-1 therapy in moderate to critical COVID-19 patients: a systematic review, meta-analysis, and meta-regression

BACKGROUND

Effort to search for the optimal COVID-19 treatment has continuously been attempted. Thymosin alpha-1 have immunomodulatory properties which may be beneficial in case of viral infection. This study's goal is to determine whether thymosin alpha-1 is effective in treating people with moderate-to-severe COVID-19.

METHODS

We searched for literature in 4 database: Scopus, Europe PMC, Medline, ClinicalTrials.gov, and Cochrane Library until March 25th, 2023. If those articles have data on the efficacy of thymosin alpha-1 therapy on COVID-19, they would be included. Risk ratio (RR) and Mean Difference (MD) along with their 95% confidence intervals were used to pool the results of dichotomous and continuous variables, respectively.

RESULTS

Pooled data from 8 studies indicated that moderate to critical Covid-19 patients who were receiving thymosin alpha-1 therapy had significantly lower mortality from COVID-19 (RR 0.59; 95% CI 0.37-0.93, p = 0.02, I2 = 84%), but without any difference in the needs for mechanical ventilation (RR 0.83; 95% CI 0.48-1.44, p = 0.51, I2 = 74%) and hospital length of stay (MD 2.32; 95% CI - 0.93, 5.58, p = 0.16, I2 = 94%) compared to placebo. The benefits of thymosin alpha-1 on the mortality rate were significantly affected only by sample size (p = 0.0000) and sex (p = 0.0117).

CONCLUSION

Our study suggests that treatment with thymosin alpha-1 may reduce mortality rate in moderate to critical COVID-19 patients. Randomized clinical trials (RCTs) are still required to verify the findings of our study.

Therapeutic applications of thymosin peptides: a patent landscape 2018-present

INTRODUCTION

Thymosins are small proteins found mainly in the thymus. They are involved in several biological processes, including immunoregulation, angiogenesis, and anti-inflammatory activity. Due to these multiple activities, thymosins are widely used as therapeutics. In fact, these peptides have shown interesting results in the treatment of eye disorders, anticancer therapy, and dysregulated immune disorders.

AREA COVERED

We analyzed the thymosins therapeutic patent landscape describing the most significant patents published after 2018 and originally written in English, classified according to the different type of functions and diseases. We searched 'Thymosin' on Patentscope and Espacenet.

EXPERT OPINION

Thymalfasin (Zadaxin) is the only FDA-approved thymosine-based drug used to treat chronic hepatitis B and C and as a chemotherapy inducer. This outcome demonstrates how thymosins can be exploited as therapeutics, especially in immunological and anti-cancer therapies. However, the development of modified thymosins could expand their therapeutic interest and application in different diseases. In fact, by chemical modifications, it is possible to increase proteolytic stability in the biological environment, enhance cell permeability, and stabilize the secondary structure of the peptide. Finally, the development of shorter sequences could reduce the cost and production time of these thymosin-based drugs.

Factors associated with the humoral response after three doses of COVID-19 vaccination in kidney transplant recipients

Introduction

Kidney transplant recipients showed a weak humoral response to the mRNA COVID-19 vaccine despite receiving three cumulative doses of the vaccine. New approaches are still needed to raise protective immunity conferred by the vaccine administration within this group of high-risk patients.

Methods

To analyze the humoral response and identify any predictive factors within these patients, we designed a prospective monocentric longitudinal study of Kidney transplant recipients (KTR) who received three doses of mRNA-1273 COVID-19 vaccine. Specific antibody levels were measured by chemiluminescence. Parameters related to clinical status such as kidney function, immunosuppressive therapy, inflammatory status and thymic function were analyzed as potential predictors of the humoral response.

Results

Seventy-four KTR and sixteen healthy controls were included. One month after the administration of the third dose of the COVID-19 vaccine, 64.8% of KTR showed a positive humoral response. As predictive factors of seroconversion and specific antibody titer, we found that immunosuppressive therapy, worse kidney function, higher inflammatory status and age were related to a lower response in KTR while immune cell counts, thymosin-a1 plasma concentration and thymic output were related to a higher humoral response. Furthermore, baseline thymosin-a1 concentration was independently associated with the seroconversion after three vaccine doses.

Discussion

In addition to the immunosuppression therapy, condition of kidney function and age before vaccination, specific immune factors could also be relevant in light of optimization of the COVID-19 vaccination protocol in KTR. Therefore, thymosin-a1, an immunomodulatory hormone, deserves further research as a potential adjuvant for the next vaccine boosters.

Identification and determination of structurally related peptide impurities in thymalfasin by liquid chromatography-high-resolution mass spectrometry

Thymalfasin is an important peptide drug widely used for the single or combination treatment of hepatitis, sepsis, cancer, and immunodeficiency. Accurate purity assessment of thymalfasin material is essential for thymalfasin certified reference materials (CRMs) production and analytical method validation, in which comprehensive determination of thymalfasin-related impurities is required to avoid quantitative bias. In this study, liquid chromatography-high-resolution mass spectrometry (LC-hrMS) methods have been established to comprehensively characterize and quantify thymalfasin-related impurities using a thymalfasin China Pharmacopoeia (ChP) standard and then successfully applied to three commercial thymalfasin materials. A total of twenty-three thymalfasin-related impurities (> 0.1 mg/g) were separated, identified, and quantified in the ChP standard analyzed. The major impurities existing in thymalfasin ChP standard and commercial materials include deamination, amination, succinimide, amino acid insertion/deletion, dimers, and isomers at different mass fraction levels. In particular, over half of the thymalfasin-related impurities were found directly or indirectly arising from the labile C-terminal asparagine (Asn) residue. Given the 28th Asn residue at the C-terminus is not necessary for the biological activity of thymalfasin as reported previously, thus deletion, replacement, or modification of thymalfasin C-terminal Asn residue is proposed for new drug research and development. In summary, these results provide a further complement to the thymalfasin-related impurity profile and issue a warning for protection or processing of the thymalfasin C-terminal Asn residue.

Efficacy of thymosin α1 in management of radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy: A Phase 2 Clinical Trial (GASTO-1043)

PURPOSE

To evaluate the efficacy of thymosin α1 in management of radiation pneumonitis (RP) in patients with locally advanced non-small cell lung cancer (LANSCLC) treated with concurrent chemoradiotherapy (CCRT).

METHODS AND MATERIALS

This phase II, single-arm trial enrolled patients with unresectable LANSCLC of 18 to 75 years' old and an Eastern Cooperative Oncology Group performance status of 0 to 1. Eligible patients received definitive CCRT and weekly thymosin α1 from the start of CCRT till 2 months after CCRT. Patients were administered 51 Gy in 17 daily fractions or 40 Gy in 10 daily fractions in the first course followed by a re-evaluation and those patients without disease progression had an adaptive plan of 15 Gy in 5 daily fractions or 24 Gy in 6 daily fractions as a boost. Concurrent chemotherapy consisted of weekly docetaxel (25 mg/m²) and nedaplatin (25 mg/m²) during radiation therapy. The primary endpoint was the incidence of Grade (G) ≥2 RP. Secondary endpoints included the incidence of late pulmonary fibrosis, total lymphocyte count (TLC), serum C-reactive protein (CRP) levels, and the composition of gut microbiota. TLC and CRP data were collected at baseline, 2-3 weeks during CCRT, the end of CCRT, 2 and 6 months after CCRT. Fecal samples were collected at baseline and the end of CCRT. Patients treated with CCRT but without thymosin α1 intervention during the same period were selected as the control group by the propensity score matching method.

RESULTS

Sixty-nine patients were enrolled in the study, and another 69 patients were selected as the control group. The incidence of G≥2 RP was lower in the study group compared with control cases (36.2% vs 53.6%, P=0.040). G1 late pulmonary fibrosis occurred in 2 (3.7%) patients of the control group compared with no event in the study group (P=0.243). Compared with the control group, the incidence of G3-4 lymphopenia (19.1% vs. 62.1%, P<0.001) was lower, and the median TLC nadir (0.51 k/µL vs. 0.30 k/µL, P<0.001) was higher in the study group. The proportion of patients with maximum CRP≥100 mg/L was lower in the study group (13.8% vs. 29.7% P=0.029). The diversity and community composition of the gut microbiota were not significantly different between the two groups.

CONCLUSIONS

Administration of thymosin α1 during and after CCRT was associated with significant reductions in G≥2 RP and G3-4 lymphopenia in patients with LANSCLC compared to historic controls.

A Review on Measures to Rejuvenate Immune System: Natural Mode of Protection Against Coronavirus Infection

SARS-CoV-2, a novel Corona virus strain, was first detected in Wuhan, China, in December 2019. As of December 16, 2021, almost 4,822,472 people had died and over 236,132,082 were infected with this lethal viral infection. It is believed that the human immune system is thought to play a critical role in the initial phase of infection when the viruses invade the host cells. Although some effective vaccines have already been on the market, researchers and many bio-pharmaceuticals are still working hard to develop a fully functional vaccine or more effective therapeutic agent against the COVID-19. Other efforts, in addition to functional vaccines, can help strengthen the immune system to defeat the corona virus infection. Herein, we have reviewed some of those proven measures, following which a more efficient immune system can be better prepared to fight viral infection. Among these, dietary supplements like- fresh vegetables and fruits offer a plentiful of vitamins and antioxidants, enabling to build of a healthy immune system. While the pharmacologically active components of medicinal plants directly aid in fighting against viral infection, supplementary supplements combined with a healthy diet will assist to regulate the immune system and will prevent viral infection. In addition, some personal habits, like- regular physical exercise, intermittent fasting, and adequate sleep, had also been proven to aid the immune system in becoming an efficient one. Maintaining each of these will strengthen the immune system, allowing innate immunity to become a more defensive and active antagonistic mechanism against corona-virus infection. However, because dietary treatments take longer to produce beneficial effects in adaptive maturation, personalized nutrition cannot be expected to have an immediate impact on the global outbreak.

Thymopentin-Mediated Inhibition of Cancer Stem Cell Stemness Enhances the Cytotoxic Effect of Oxaliplatin on Colon Cancer Cells

Thymopentin (TP5) is an immunomodulatory pentapeptide that has been widely used in malignancy patients with immunodeficiency due to radiotherapy and chemotherapy. Here, we propose that TP5 directly inhibits the stemness of colon cancer cells HCT116 and therefore enhances the cytotoxicity of oxaliplatin (OXA) in HCT116 cells. In the absence of serum, TP5 was able to induce cancer stemness reduction in cultured HCT116 cells and significantly reduced stemness-related signals, such as the expression of surface molecular markers (CD133, CD44 and CD24) and stemness-related genes (ALDH1, SOX2, Oct-4 and Nanog), and resulted in altered Wnt/β-catenin signaling. Acetylcholine receptors (AchRs) are implicated in this process. OXA is a common chemotherapeutic agent with therapeutic effects in various cancers. Although TP5 had no direct effect on the proliferation of HCT116, this pentapeptide significantly increased the sensitivity of HCT116 to OXA, where the effect of TP5 on the stemness of colon cancer cells through stimulation of AchRs may contribute to this process. Our results provide a promising strategy for increasing the sensitivity of colon cancer cells to chemotherapeutic agents by incorporating immunomodulatory peptides.

Clinical efficacy of thymosin alpha 1 combined with multi-modality chemotherapy and its effects on immune function of patients with pulmonary tuberculosis complicated with diabetes

Objective:

To observe the clinical efficacy of thymosin alpha 1 (Tα1) combined with multi-modality chemotherapy in patients with pulmonary tuberculosis (PTB) complicated with diabetes and discuss the effects of such combination therapy on lymphocyte subsets and sputum levels of cytokines.

Methods:

A total of 120 patients with PTB complicated with diabetes admitted to the Affiliated Hospital of North China University of Science and Technology from January 2017 to January 2018 were included in this study and randomly divided into an experimental group (Tα1 group, n=60) and a control group (n=60). Clinical efficacy and adverse drug reactions were observed and compared between the two groups. Blood samples were collected for lymphocyte (NK cell and T cell subsets) levels by flow cytometry, and sputum samples were collected for cytokine (IL-2, IFN-γ, IL-4 and TNF-α) levels by ELISA.

Results:

Two groups showed no statistically significant difference in sputum culture-negative conversion rate, chest lesion absorption rate, and cavity closure rate (P>0.05) after 6 months of treatment. However, after 12 months, the sputum culture-negative conversion rate, chest lesion absorption rate, and cavity closure rate in the Tα1 group increased compared with the control group, and the differences were statistically significant (P<0.05). There was a significant increase in CD3+, CD4+, NK-cells lymphocytes after six months in the Tα1 group than in the control group, whereas the CD8+, Th17, Treg lymphocytes in the Tα1 group were substantially lower than in the control group, with the differences showing statistical significance (P<0.05, respectively). After six months of treatment, the sputum supernatant levels of interleukin-4 (IL-4) and tumor necrosis factor α (TNF-α) in the Tα1 group were lower than in the control group, whereas the sputum supernatant levels of interleukin-2 (IL-2) and interferon gamma (IFN-γ) in the Tα1 group were higher than in the control group, and the differences were statistically significant (P<0.05, respectively). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P>0.05).

Conclusion:

Tα1 combined with multi-modality chemotherapy has a visible curative effect on PTB patients with diabetes as it can regulate immune function and reduce the levels of inflammatory cytokines. As a safe combination therapy, it seems promising for further use in clinical practice.

DNA Dendrons as Agents for Intracellular Delivery

Herein, a method for synthesizing and utilizing DNA dendrons to deliver biomolecules to living cells is reported. Inspired by high-density nucleic acid nanostructures, such as spherical nucleic acids, we hypothesized that small clusters of nucleic acids, in the form of DNA dendrons, could be conjugated to biomolecules and facilitate their cellular uptake. We show that DNA dendrons are internalized by 90% of dendritic cells after just 1 h of treatment, with a >20-fold increase in DNA delivery per cell compared with their linear counterparts. This effect is due to the interaction of the DNA dendrons with scavenger receptor-A on cell surfaces, which results in their rapid endocytosis. Moreover, when conjugated to peptides at a single attachment site, dendrons enhance the cellular delivery and activity of both the model ovalbumin 1 peptide and the therapeutically relevant thymosin alpha 1 peptide. These findings show that high-density, multivalent DNA ligands play a significant role in dictating cellular uptake of biomolecules and consequently will expand the scope of deliverable biomolecules to cells. Indeed, DNA dendrons are poised to become agents for the cellular delivery of many molecular and nanoscale materials.

Interferon α2-Thymosin α1 Fusion Protein (IFNα2-Tα1): A Genetically Engineered Fusion Protein with Enhanced Anticancer and Antiviral Effect

Human interferon α2 (IFNα2) and thymosin α1 (Tα1) are therapeutic proteins used for the treatment of viral infections and different types of cancer. Both IFNα2 and Tα1 show a synergic effect in their activities when used in combination. Furthermore, the therapeutic fusion proteins produced through the genetic fusion of two genes can exhibit several therapeutic functions in one molecule. In this study, we determined the anticancer and antiviral effect of human interferon α2-thymosin α1 fusion protein (IFNα2-Tα1) produced in our laboratory for the first time. The cytotoxic and genotoxic effect of IFNα2-Tα1 was evaluated in HepG2 and MDA-MB-231 cells. The in vitro assays confirmed that IFNα2-Tα1 inhibited the growth of cells more effectively than IFNα2 alone and showed an elevated genotoxic effect. The expression of proapoptotic genes was also significantly enhanced in IFNα2-Tα1-treated cells compared to IFNα2-treated cells. Furthermore, the HCV RNA level was significantly reduced in IFNα2-Tα1-treated HCV-infected Huh7 cells compared to IFNα2-treated cells. The quantitative PCR analysis showed that the expression of various genes, the products of which inhibit HCV replication, was significantly enhanced in IFNα2-Tα1-treated cells compared to IFNα2-treated cells. Our findings demonstrate that IFNα2-Tα1 is more effective than single IFNα2 as an anticancer and antiviral agent.

Combination of Gemcitabine and Thymosin alpha 1 exhibit a better anti-tumor effect on nasal natural killer/T-cell lymphoma

BACKGROUND

Nasal natural killer/T-cell lymphoma (NNKTL) is an aggressive and poor prognostic malignant tumor along with high-level infection of Epstein-Barr virus (EBV). Gemcitabine (Gem) and Thymosin alpha 1 (Tα1) exert an anti-tumor effect in various cancers. However, the effect of the combination of Gem and Tα1 in NNKTL remains unknown.

METHODS

SNK6 cells were treated with Gem, Tα1 and Gem plus Tα1 for 48 h. The expression levels of EBV and inflammatory factors were measured by qRT-PCR assay. The effect of Gem and Tα1 on cell viability, proliferation, apoptosis, autophagy was detected by CCK-8, colony formation, flow cytometry, autophagic flux measurement, respectively. Western blot was used to evaluate the expression of proteins related to epithelial-mesenchymal transition (EMT), apoptosis and autophagy. In vivo xenograft models were used to further verify the roles of Gem and Tα1. Tumors were removed for weight measurement, H&E and IHC staining.

RESULTS

We identified that the half maximal inhibitory concentration (IC50) of Gem and Tα1 was 116.5 μmol/ml and 1.334 μmol/ml. Alone or combined administration of Gem and Tα1 dramatically attenuated the EBV viral load and promoted inflammatory factors expression in SNK6 cells, among which the combination of Gem and Tα1 treatment showed the most significant effect. Besides, combination treatment with Gem and Tα1 markedly inhibited cell growth and EMT progress, and enhanced apoptosis and autophagy. Similarly, Gem combined with Tα1 suppressed tumor growth, promoted apoptosis and autophagy in vivo. Additionally, combination treatment with Gem and Tα1 inhibited PI3K/AKT/mTOR pathway.

CONCLUSION

In summary, combination administration of Gem and Tα1 suppressed the progression of NNKTL in vivo and in vitro. Our study provided an effective therapeutic strategy potentially for the clinical treatment of NNKTL.

Thymosin alpha 1: A comprehensive review of the literature

Thymosin alpha 1 is a peptide naturally occurring in the thymus that has long been recognized for modifying, enhancing, and restoring immune function. Thymosin alpha 1 has been utilized in the treatment of immunocompromised states and malignancies, as an enhancer of vaccine response, and as a means of curbing morbidity and mortality in sepsis and numerous infections. Studies have postulated that thymosin alpha 1 could help improve the outcome in severely ill corona virus disease 2019 patients by repairing damage caused by overactivation of lymphocytic immunity and how thymosin alpha 1 could prevent the excessive activation of T cells. In this review, we discuss key literature on the background knowledge and current clinical uses of thymosin alpha 1. Considering the known biochemical properties including antibacterial and antiviral properties, time-honored applications, and the new promising findings regarding the use of thymosin, we believe that thymosin alpha 1 deserves further investigation into its antiviral properties and possible repurposing as a treatment against severe acute respiratory syndrome coronavirus-2.

Modified Thymosin Alpha 1 Distributes and Inhibits the Growth of Lung Cancer in Vivo

Targeted therapy of tumors is an effective method for treating cancer. Thymosin alpha 1 (Tα1), a hormone that contains 28 amino acids, is already approved for cancer treatment. However, its clinical application is limited because of the lack of tumor targeting. Considering that RGD can specifically bind to integrin, the anticancer drug can have a targeted therapeutic effect on tumors when it combines with a peptide containing an RGD sequence. We produced a polypeptide, Tα1-RGDR, by binding Tα1 to RGDR. The RGDR can combine with the αvβ3 and NRP-1 domains, which are highly expressed on the surface of the tumor, to achieve the effect of tumor targeting. This work aimed to investigate the difference of antitumor activity and tumor targeting between Tα1 modified by RGDR and Tα1 by using H460 and LLC tumor models. Results showed that Tα1-RGDR had remarkable antitumor effects, and its tumor targeting was better than that of Tα1. Hence, Tα1-RGDR is a promising antitumor drug.

ThymicPeptides Reverse Immune Exhaustion in Patients with Reactivated Human Alphaherpesvirus1 Infections

Recurrent infection with human alphaherpesvirus 1 (HHV-1) may be associated with immune exhaustion that impairs virus elimination. Thymic peptides enhance immune function and thus could overcome immune exhaustion. In this study, we investigated whether reactivation of herpes infections was associated with immune exhaustion. Moreover, we examined the impact of treatment with thymostimulin on the expression of programmed cell death protein 1 (PD-1) and its ligand (PD-L1) on T and B lymphocytes in patients suffering from recurrent HHV-1 reactivation. We also assessed the effector function of peripheral blood mononuclear cells (PBMCs) after stimulation with thymic peptides. We enrolled 50 women with reactivated HHV-1 infections and healthy volunteers. We measured the expression of various activation and exhaustion markers on the surface of PBMCs using flow cytometry. In ex vivo experiments, we measured the secretion of inflammatory cytokines by PBMCs cultured with thymostimulin. Compared with controls, patients with reactivated HHV-1 infections had increased percentages of CD3+ co-expressing CD25, an activation marker (p < 0.001). Moreover, these patients had increased percentages of CD4+ and CD8+ cells co-expressing the inhibitory markers PD-1 and PD-L1. In cultures of PBMCs from the patients, thymostimulin increased the secretion of interferon gamma (p < 0.001) and interleukin (IL)-2 (p = 0.023), but not IL-4 or IL-10.Two-month thymostimulin therapy resulted in no reactivation of HHV-1 infection during this period and the reduction of PD-1 and PD-L1 expression on the surface of T and B lymphocytes (p < 0.001). In conclusion, reactivation of herpes infection is associated with immune exhaustion, which could be reversed by treatment with thymic peptides.

High yield expression, characterization, and biological activity of IFNα2-Tα1 fusion protein

The use of interferon α-2 in combination with thymosin α-1 shows higher anti-cancer effect in comparison when both are used individually because of their synergistic effects. In this study we produced an important human interferon α-2-thymosin α-1 (IFNα2-Tα1) fusion protein with probable pharmaceutical properties coupled to its high-level expression, characterization, and study of its biological activity. The IFNα2-Tα1 fusion gene was constructed by over-lap extension PCR and expressed in Escherichia coli expression system. The expression of IFNα2-Tα1 fusion protein was optimized to higher level and its maximum expression was obtained in modified terrific broth medium when lactose was used as inducer. The fusion protein was refolded into its native biologically active form with maximum yield of 83.14% followed by purification with ∼98% purity and 69% final yield. A band of purified IFNα2-Tα1 fusion protein equal to ∼23 kDa was observed on 12 % SDS-PAGE gel. The integrity of IFNα2-Tα1 fusion protein was confirmed by western blot analysis and secondary structure was assessed by CD spectroscopy. When IFNα2-Tα1 fusion protein was subjected to its biological activity analysis it was observed that it exhibits both IFNα2 & Tα1 activities as well as significantly higher anticancer activity as compared to IFNα-2 alone.

Subtiligase-Catalyzed Peptide Ligation

Subtiligase-catalyzed peptide ligation is a powerful approach for site-specific protein bioconjugation, synthesis and semisynthesis of proteins and peptides, and chemoproteomic analysis of cellular N termini. Here, we provide a comprehensive review of the subtiligase technology, including its development, applications, and impacts on protein science. We highlight key advantages and limitations of the tool and compare it to other peptide ligase enzymes. Finally, we provide a perspective on future applications and challenges and how they may be addressed.

Thymosin alpha-1; a natural peptide inhibits cellular proliferation, cell migration, the level of reactive oxygen species and promotes the activity of antioxidant enzymes in human lung epithelial adenocarcinoma cell line (A549)

This research was conducted to investigate the biochemical effects of thymosin alpha-1 using human lung cancer cells (A549). The A549 cells were treated with different concentrations of Thα1 for 24 h and the growth, inhibition of cells was determined. Thα1 revealed anti-proliferative effect at 24 and 48 μg/ml after 24 h. Furthermore, it indicated antioxidant properties by significantly enhancing the activity of catalase (12 μg/ml), superoxide dismutase (6 and 12 μg/ml), and glutathione peroxidase (3, 6 and 12 μg/ml) and reducing the production of cellular ROS. Our results showed that Thα1 inhibits the migration of A549 cells in a concentration-dependent manner after 24 and 48 h. Moreover, the effect of Thα1 on apoptosis was investigated by Hoechst 33342 staining and cell cycle analysis. Results demonstrated no significant effect on the induction of apoptosis in A549 cells. In conclusion, our results showed the antioxidant properties of Thα1 on A549 cancer cells.

Development and application of a high-throughput liquid chromatography-tandem mass spectrometric method for the simultaneous determination of thymosin α1 and its recombinant human form in plasma and urine

Thymosin α1 (Thymalfasin, Tα1) is a naturally occurring polypeptide widely used as an immune system enhancer for the treatment of HIV/AIDS, hepatitis B and C, and cancer. Recombinant human Tα1 (rh-Tα1) lacking N-terminal acetylation (NTA) displays similar biological activity to Tα1 and has completed phase III clinical trials in China. To compare the pharmacokinetics of rh-Tα1 and Tα1 and establish whether they undergo mutual transmutation in vivo, we developed a novel bioassay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of the two peptides in human plasma and urine. Sample preparation by protein precipitation using a mixture of methanol and perchloric acid was followed by HPLC on a Zorbax 300SB-C18 column (150 × 4.6 mm, 5 μm) maintained at 40 °C. Detection was by multiple reaction monitoring (MRM) of the precursor-to-product ion transitions at m/z 778.0→316.0 for Tα1, m/z 767.3→955.0 for rh-Tα1 and m/z 832.3→159.2 for the internal standard, eptifibatide. The method was linear in the range 2-100 ng/mL for both analytes with good accuracy and precision. High sample throughput was facilitated by inclusion of a parallel two-column chromatographic system. The method was successfully applied to a comparative pharmacokinetic study involving single subcutaneous injections of either Tα1 or rh-Tα1 to two groups of healthy male volunteers. The results indicate that rh-Tα1 undergoes NTA in vivo to form Tα1 but that Tα1 is not deacetylated to rh-Tα1.

Antioxidant and angiotensin-converting enzyme (ACE) inhibitory activity of thymosin alpha-1 (Thα1) peptide

In this research, the antioxidant property of thymosin alpha-1 (Thα1) peptide was investigated through various antioxidant methods. Thα1 showed 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (IC₅₀ = 20 µM) and its 2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) scavenging reached 45.33% at 80 µM (IC₅₀ = 85 µM). In addition, hydroxyl and superoxide radical scavenging of Thα1 peptide exhibited a concentration-depended manner. The IC₅₀ values of hydroxyl and superoxide radical scavenging were estimated to be 82 µM and 20 µM, respectively. The effect of Thα1 on eliminating superoxide radicals was higher (62.23%) than other antioxidant assays. Moreover, the antioxidant activity of Thα1 peptide was evaluated by measuring cellular reactive oxygen species (ROS). Results indicated that Thα1 decreased the generation of ROS level in 1321 N1 human neural asterocytoma cells. The inhibitory effect of Thα1 on angiotensin-converting enzyme (ACE) was determined. The kinetic parameters (K_m and V_max) and the inhibition pattern were examined. Based on the Lineweaver-Burk plot, Thα1 displayed a mixed inhibition pattern. The IC₅₀ and K_i values of Thα1 were 0.8 µM and 3.33 µM, respectively. Molecular modeling suggested that Thα1 binds to ACE-domains with higher affinity binding to N-domain with the binding energy of -22.87 kcal/mol. Molecular docking indicated that Thα1 interacted with ACE enzyme (N- and C-domains) due to electrostatic, hydrophobic, and hydrogen forces. Our findings suggested that Thα1 possess a multifunctional peptide with dual antioxidant and ACE-inhibitory properties. Further researches are needed to investigate the antioxidant and anti-hypertensive effect of Thα1 both in vitro and in vivo.

Design of a substrate-tailored peptiligase variant for the efficient synthesis of thymosin-α1

The synthesis of thymosin-α₁, an acetylated 28 amino acid long therapeutic peptide, via conventional chemical methods is exceptionally challenging. The enzymatic coupling of unprotected peptide segments in water offers great potential for a more efficient synthesis of peptides that are difficult to synthesize. Based on the design of a highly engineered peptide ligase, we developed a fully convergent chemo-enzymatic peptide synthesis (CEPS) process for the production of thymosin-α₁via a 14-mer + 14-mer segment condensation strategy. Using structure-inspired enzyme engineering, the thiol-subtilisin variant peptiligase was tailored to recognize the respective 14-mer thymosin-α₁ segments in order to create a clearly improved biocatalyst, termed thymoligase. Thymoligase catalyzes peptide bond formation between both segments with a very high efficiency (>94% yield) and is expected to be well applicable to many other ligations in which residues with similar characteristics (e.g. Arg and Glu) are present in the respective positions P1 and P1'. The crystal structure of thymoligase was determined and shown to be in good agreement with the model used for the engineering studies. The combination of the solid phase peptide synthesis (SPPS) of the 14-mer segments and their thymoligase-catalyzed ligation on a gram scale resulted in a significantly increased, two-fold higher overall yield (55%) of thymosin-α₁ compared to those typical of existing industrial processes.

Asparaginyl Endopeptidase (Legumain) Supports Human Th1 Induction via Cathepsin L-Mediated Intracellular C3 Activation

Autocrine activation of the complement receptors C3aR and CD46 by complement activation components C3a and C3b produced through C3 cleavage by the protease cathepsin L (CTSL) during T cell stimulation is a requirement for IFN-γ production and Th1 induction in human CD4⁺ T cells. Thus, lack of autocrine CD46 activation, such as in CD46-deficient patients, is associated with defective Th1 responses and recurrent infections. We have identified LGMN [the gene coding for legumain, also known as asparaginyl endopeptidase (AEP)] as one of the key genes induced by CD46 co-stimulation during human CD4⁺ T cell activation. AEP processes and activates a range of proteins, among those α1-thymosin and CTSL, which both drive intrinsically Th1 activity-but has so far not been described to be functionally active in human T cells. Here we found that pharmacological inhibition of AEP during activation of human CD4⁺ T cells reduced CTSL activation and the CTSL-mediated generation of intracellular C3a. This translated into a specific reduction of IFN-γ production without affecting cell proliferation or survival. In line with these findings, CD4⁺ T cells isolated from Lgmn ^-/- mice also displayed a specific defect in IFN-γ secretion and Th1 induction. Furthermore, we did not observe a role for AEP-driven autocrine α1-thymosin activation in T cell-derived IFN-γ production. These data suggest that AEP is an "upstream" activator of the CTSL-C3-IFN-γ axis in human CD4⁺ T cells and hence an important supporter of human Th1 induction.

Thymosin α1 suppresses migration and invasion of PD-L1 high-expressing non-small-cell lung cancer cells via inhibition of STAT3-MMP2 signaling

Background

Thymosin α1 (Tα1) is one of the most commonly used immunomodulators for metastatic non-small-cell lung cancer (NSCLC) patients in many countries. Despite the identification of the direct suppression on cancer cell proliferation, little is known about its effect on metastasis and metastasis-related signaling such as matrix metalloproteinases (MMPs) and programmed cell death ligand 1 (PD-L1).

Materials and methods

NSCLC cells with distinguishing PD-L1 expression levels were treated with Tα1. siRNAs were used to knockdown PD-L1. Cell migration and invasion abilities were evaluated by wound-healing and transwell assays. The xenograft model by BALB/c nude mice was constructed to test the inhibitory effect of Tα1 on metastasis in vivo. The expression levels of metastasis-related signaling pathways and key molecules were assessed by Western blot (WB) and quantitative reverse transcriptase PCR (qRT-PCR).

Results

Tα1 significantly suppressed cell migration and invasion in PD-L1 high-expressing H1299, NL9980, and L9981 cells but not in PD-L1 low-expressing A549 or SPC-A-1 cells. This difference was demonstrated by mouse model in vivo as well. Knocking down of PD-L1 significantly impaired the inhibition of cell migration and invasion caused by Tα1 treating in PD-L1 high-expressing cells. Besides, Tα1 inhibited the activation and translocation of STAT3 and the expression of MMP2 in PD-L1 high-expressing NSCLC cells. Moreover, the treatment of STAT3 activator colivelin could partly reverse the Tα1-induced MMP2 suppression and the migration phenotype.

Conclusion

Tα1 significantly suppresses migration and invasion in PD-L1 high-expressing NSCLC cells compared with PD-L1 low-expressing NSCLC cells in vitro and in vivo, through the downregulation of STAT3–MMP2 signaling. These different responses to Tα1, together with the depiction of Tα1-induced signaling changes, suggest a potential benefit of Tα1 for PD-L1-positive NSCLC patients, enlightening the combination of Tα1 with target therapy or immune checkpoint inhibitors.

A novel mechanism of tumor-induced thymic atrophy in mice bearing H22 hepatocellular carcinoma

Background

Thymic atrophy was discovered in tumor-bearing mice in recent years.

Methods

Flow cytometry was carried out including Annexin V-FITC/PI double staining, PI staining, Terminal dUTP nick-end labeling, CD3-FITC/CD19-PE and CD8-FITC/CD4-PE double staining. Enzyme-linked immunosorbent assay and polymerase chain reaction were also investigated.

Results

According to our experiments, we demonstrated that no signs of apoptosis in thymocytes were found in H22-bearing mice, while the proportions of CD4⁺ T cells and CD8⁺ T cells in thymuses were remarkably increased, the opposite tendency was found in peripheral bloods, and only CD3⁺CD8⁺ T cells were discovered in H22 solid tumors. We further discovered that the level of thymosin alpha 1 (Tα1) and the expression of Wnt4 in thymus of H22-bearing mice were significantly improved than control, which indicated the active proliferation and differentiation of thymocytes. Our study revealed that CD8⁺ T cells could not effectively eliminate H22 cells independently when CD4⁺ T cells were suppressed by tumors, while the body would only enhance the differentiation and maturation of T cells in thymuses and release them to solid tumor to reinforce antitumor immunocompetence, leading to a vicious cycle which finally led to thymic atrophy.

Conclusion

Our data propose a novel mechanism of tumor-induced thymic atrophy regulated by abnormal immunoreaction and may provide new ideas for the immunotherapy of tumors.

Immune regulation effect of lienal polypeptides extract in Lewis lung carcinoma-bearing mice treated with cyclophosphamide

Polypeptides extracted from animal immune organs have been proved to exert immunomodulatory activities in previous reports. However, relative experimental data regarding the influence of a polypeptide mixture extracted from healthy calf spleen (lienal polypeptide [LP]) on the immune function in tumor therapy are limited, and the components in LP remain unclear. In the present study, the immune regulatory effect of LP was investigated in normal mice and Lewis lung carcinoma (LLC)-bearing mice treated with cyclophosphamide (CTX). The components of LP were identified by liquid chromatography-electrospray ionization-coupled with tandem mass spectrometry (LC-MS/MS) analysis and bioinformatic analysis. In LLC-bearing mice, LP showed a synergic antitumor effect with CTX, whereas LP alone did not present direct antitumor activity. Further, LP was found to enhance immune organ indexes, splenocyte number, and T lymphocyte subsets in normal mice and LLC-bearing mice treated with CTX. The decline of white blood cell and platelet counts, splenocyte proliferation activity, and peritoneal macrophage phagocytic function caused by CTX were also significantly suppressed by LP treatment in LLC-bearing mice. Notably, LP treatment significantly decreased the expression of phagocytosis-related proteins including CD47/signal regulatory protein α/Src homology phosphatase-1 in the tumor tissue of LLC-bearing mice treated with CTX. LC-MS/MS-based peptidomics unraveled the main polypeptides in LP with a length from 8 to 25 amino acids. Bioinformatics analysis further confirmed the possibility of LP to regulate immunity, especially in phagocytosis-related pathway. Our above findings indicated that LP can relieve the immunosuppression induced by chemotherapy and is a beneficial supplement in cancer therapy. Impact statement The immunomodulatory activities of polypeptides extracted from animal immune organs have incurred people's interests since a long time ago. In this study, we investigated the immune regulation effects of a polypeptide mixture extracted from health calf spleen (lienal polypeptide [LP]) in Lewis lung carcinoma-bearing mice treated with cyclophosphamide (CTX). Liquid chromatography-electrospray ionization-coupled with tandem mass spectrometry-based peptidomics and bioinformatics analysis unraveled the main polypeptides in LP and further confirmed that LP is mainly associated with immune regulating pathway, especially in tumor cell phagocytosis-related pathway. Our study for the first time revealed that polypeptides from spleen can relieve the immunosuppression induced by CTX and is a beneficial supplement in cancer therapy.

Cinnamomols A and B, Immunostimulative Diterpenoids with a New Carbon Skeleton from the Leaves of Cinnamomum cassia

Two diterpenoids with an unprecedented diterpene carbon skeleton, cinnamomols A (1) and B (2), were isolated from the leaves of Cinnamomum cassia. 1 and 2 feature a cage-like, rigid, 5/5/5/5/5/6-fused hexacyclic ring system. The structures of 1 and 2 were established by extensive spectroscopic techniques and single-crystal X-ray diffraction, and their plausible biosynthetic pathways were proposed. 1 and 2 exhibited significant in vitro immunostimulative activity, and the mode of action of 1 was investigated.

Pharmacological interventions for acute hepatitis B infection: an attempted network meta-analysis

BACKGROUND

Infection with hepatitis B virus (HBV) can be symptomatic or asymptomatic. Apart from chronic HBV infection, the complications related to acute HBV infection are severe acute viral hepatitis and fulminant hepatitis characterised by liver failure. The optimal pharmacological treatment of acute HBV infection remains controversial.

OBJECTIVES

To assess the benefits and harms of pharmacological interventions in the treatment of acute HBV infection through a network meta-analysis and to generate rankings of the available treatments according to their safety and efficacy. As it was not possible to assess whether the potential effect modifiers were similar across different comparisons, we did not perform the network meta-analysis, and instead, assessed the benefits and harms of different interventions using standard Cochrane methodological procedures.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, WHO International Clinical Trials Registry Platform, and randomised clinical trials (RCTs) registers to August 2016 to identify RCTs on pharmacological interventions for acute HBV infection.

SELECTION CRITERIA

RCTs, irrespective of language, blinding, or publication status in participants with acute HBV infection. We excluded trials if participants had previously undergone liver transplantation and had other coexisting viral diseases such as hepatitis C virus and HIV. We considered any of the various pharmacological interventions compared with each other or with placebo, or no intervention.

DATA COLLECTION AND ANALYSIS

We calculated the odds ratio (OR) and rate ratio with 95% confidence intervals (CI) using both fixed-effect and random-effects models based on available-participant analysis with Review Manager 5. We assessed risk of bias, controlled risk of random errors with Trial Sequential Analysis, and assessed the quality of the evidence using GRADE.

MAIN RESULTS

Seven trials (597 participants) met our review inclusion criteria. All trials provided information for one or more outcomes; however, five participants were excluded from analysis by study authors. All the trials were at high risk of bias. Overall, all the evidence was low or very low quality evidence because of risk of bias (downgraded one level for risk of bias), small sample size (downgraded one level for imprecision), and wide CIs (downgraded one more level for imprecision in some comparisons). Of the seven trials, six were two-armed trials, while one trial was a three-armed trial. The comparisons included hepatitis B immunoglobulin (HBIG) versus placebo (one trial; 55 participants); interferon versus placebo (two trials; 200 participants); lamivudine versus placebo or no intervention (four trials; 316 participants); lamivudine versus entecavir (one trial; 90 participants); and entecavir versus no intervention (one trial; 131 participants). One trial included only people with acute HBV with hepatic encephalopathy (i.e. people with fulminant liver failure); one trial included only people with severe acute HBV, but it did not state whether any of the people also had fulminant HBV infection; three trials excluded fulminant HBV infection; and two trials did not report the severity of acute HBV infection. The mean or median follow-up period in the trials ranged from three to 12 months in the trials that provided this information.There was no evidence of any differences in short-term mortality (less than one year) in any of the comparisons: HBIG versus placebo (OR 1.13, 95% CI 0.36 to 3.54; participants = 55; 1 trial), lamivudine versus placebo or no intervention (OR 1.29, 95% CI 0.33 to 4.99; participants = 250; 2 trials); lamivudine versus entecavir (OR 1.23, 95% CI 0.13 to 11.65; participants = 90; 1 trial), or entecavir versus no intervention (OR 1.05, 95% CI 0.12 to 9.47; participants = 131; 1 trial). The proportion of people who progressed to chronic HBV infection was higher in the lamivudine group than the placebo or no intervention group (OR 1.99, 95% CI 1.05 to 3.77; participants = 285; 3 trials) and in the lamivudine group versus entecavir group (OR 3.64, 95% CI 1.31 to 10.13; participants = 90; 1 trial). There was no evidence of a difference in the proportion of people who progressed to chronic HBV infection between the entecavir and the no intervention groups (OR 0.58, 95% CI 0.23 to 1.49; participants = 131; 1 trial). None of the trials reported progression to fulminant HBV infection. Three trials with 371 participants reported serious adverse events. There were no serious adverse events in any of the groups (no intervention: 0/183 (0%), interferon: 0/67 (0%), lamivudine: 0/100 (0%), and entecavir: 0/21 (0%)). The proportion of people with adverse events was higher in the interferon group than the placebo group (OR 348.16, 95% CI 45.39 to 2670.26; participants = 200; 2 trials). There was no evidence of a difference in the proportion of people with adverse events between the lamivudine group and the placebo or no intervention group (OR 1.42, 95% CI 0.34 to 5.94; participants = 35; 1 trial) or number of adverse events between the lamivudine group and the placebo or no intervention group (rate ratio 1.72, 95% CI 1.01 to 2.91; participants = 35; 1 trial). One trial with 100 participants reported quality of life at one week. The scale used to report the health-related quality of life was not stated and lacked information on whether higher score meant better or worse, making it difficult to interpret the results. None of the trials reported quality of life beyond one week or other clinical outcomes such as mortality beyond one year, liver transplantation, cirrhosis, decompensated cirrhosis, or hepatocellular carcinoma.Two trials received funding from pharmaceutical companies; three trials were funded by parties without any vested interest in the results or did not receive any special funding; the source of funding was not available in the remaining two trials.

AUTHORS' CONCLUSIONS

Low or very low quality evidence suggests that progression to chronic HBV infection was higher in people receiving lamivudine compared with placebo, no intervention, or entecavir. Low quality evidence suggests that interferon may increase the adverse events after treatment for acute HBV infection. Based on a very low quality evidence, there is currently no evidence of benefit of any intervention in acute HBV infection. There is significant uncertainty in the results and further RCTs are required.

Integrated proteomic platforms for the comparative characterization of medulloblastoma and pilocytic astrocytoma pediatric brain tumors: a preliminary study

A top-down/bottom-up integrated proteomic approach based on LC-MS and 2-DE analysis was applied for comparative characterization of medulloblastoma and pilocytic astrocytoma posterior cranial fossa pediatric brain tumor tissues. Although rare, primary brain tumors are the most frequent solid tumors in the pediatric age. Among them the medulloblastoma is the prevalent malignant tumor in childhood while pilocytic astrocytoma is the most common, rarely showing a malignant progression. Due to the limited availability of this kind of sample, the study was applied to pooled tumor tissues for a preliminary investigation. The results showed different proteomic profiles of the two tumors and evidenced interesting differential expression of several proteins and peptides. Top-down proteomics of acid-soluble fractions of brain tumor homogenates ascribed a potential biomarker role of malignancy to β- and α-thymosins and their truncated proteoforms and to C-terminal truncated (des-GG) ubiquitin, resulting exclusively detected or over-expressed in the highly malignant medulloblastoma. The bottom-up proteomics of the acid-soluble fraction identified several proteins, some of them in common with 2-DE analysis of acid-insoluble pellets. Peroxiredoxin-1, peptidyl-prolyl cis-trans isomerase A, triosephosphate isomerase, pyruvate kinase PKM, tubulin beta and alpha chains, heat shock protein HSP-90-beta and different histones characterized the medulloblastoma while the Ig kappa chain C region, serotransferrin, tubulin beta 2A chain and vimentin the pilocytic astrocytoma. The two proteomic strategies, with their pros and cons, well complemented each other in characterizing the proteome of brain tumor tissues and in disclosing potential disease biomarkers to be validated in a future study on individual samples of both tumor histotypes.

The road to the synthesis of "difficult peptides"

The last decade has witnessed a renaissance of peptides as drugs. This progress, together with advances in the structural behavior of peptides, has attracted the interest of the pharmaceutical industry in these molecules as potential APIs. In the past, major peptide-based drugs were inspired by sequences extracted from natural structures of low molecular weight. In contrast, nowadays, the peptides being studied by academic and industrial groups comprise more sophisticated sequences. For instance, they consist of long amino acid chains and show a high tendency to form aggregates. Some researchers have claimed that preparing medium-sized proteins is now feasible with chemical ligation techniques, in contrast to medium-sized peptide syntheses. The complexity associated with the synthesis of certain peptides is exemplified by the so-called "difficult peptides", a concept introduced in the 80's. This refers to sequences that show inter- or intra-molecular β-sheet interactions significant enough to form aggregates during peptide synthesis. These structural associations are stabilized and mediated by non-covalent hydrogen bonds that arise on the backbone of the peptide and-depending on the sequence-are favored. The tendency of peptide chains to aggregate is translated into a list of common behavioral features attributed to "difficult peptides" which hinder their synthesis. In this regard, this manuscript summarizes the strategies used to overcome the inherent difficulties associated with the synthesis of known "difficult peptides". Here we evaluate several external factors, as well as methods to incorporate chemical modifications into sequences, in order to describe the strategies that are effective for the synthesis of "difficult peptides". These approaches have been classified and ordered to provide an extensive guide for achieving the synthesis of peptides with the aforementioned features.

High-resolution mass spectrometry for thymosins detection and characterization

OBJECTIVES

The aim of this study was to characterize β and α thymosins and their proteoforms in various tissues and bodily fluids by mass spectrometry and to look at their association with a wide variety of pathologies.

METHODS

A top-down proteomic platform based on high-performance liquid chromatography (HPLC) coupled to high-resolution LTQ-Orbitrap mass spectrometry (MS) was applied to the characterization of naturally occurring peptides.

RESULTS

In addition to thymosin β4 (Tβ4) and β10 (Tβ10), several post-translational modifications of both these peptides were identified not only in bodily fluids but also in normal and pathological tissues of different origins. The analysis of tissue specimens allowed the characterization of different C-terminal truncated forms of Tβ4 and Tβ10 together with other proteolytic fragments. The sulfoxide derivative of both Tβ4 and Tβ10 and the acetylated derivatives at lysine residues of Tβ4 were also characterized. Different proteoforms of prothymosin α, parathymosin α, thymosin α1 and thymosin α11 together with diverse proteolytic fragments were identified too.

CONCLUSION

The clinical and prognostic significance and the origin of these proteoforms have to be deeply investigated.

Zebrafish pituitary gene expression before and after sexual maturation

Sexual maturation and somatic growth cessation are associated with adolescent development, which is precisely controlled by interconnected neuroendocrine regulatory pathways in the endogenous endocrine system. The pituitary gland is one of the key regulators of the endocrine system. By analyzing the RNA sequencing (RNA-seq) transcriptome before and after sexual maturation, in this study, we characterized the global gene expression patterns in zebrafish pituitaries at 45 and 90 days post-fertilization (dpf). A total of 15 043 annotated genes were expressed in the pituitary tissue, 3072 of which were differentially expressed with a greater than or equal to twofold change between pituitaries at 45 and 90 dpf. In the pituitary transcriptome, the most abundant transcript was gh. The expression levels of gh remained high even after sexual maturation at 90 dpf. Among the eight major pituitary hormone genes, lhb was the only gene that exhibited a significant change in its expression levels between 45 and 90 dpf. Significant changes in the pituitary transcripts included genes involved in the regulation of immune responses, bone metabolism, and hormone secretion processes during the juvenile-sexual maturity transition. Real-time quantitative PCR analysis was carried out to verify the RNA-seq transcriptome results and demonstrated that the expression patterns of the eight major pituitary hormone genes did not exhibit a significant gender difference at 90 dpf. For the first time, we report the quantitative global gene expression patterns at the juvenile and sexual maturity stages. These expression patterns may account for the dynamic neuroendocrine regulation observed in body metabolism.