Molecular analysis of thymopentin binding to HLA-DR molecules

Physics of biomolecular recognition and conformational dynamics

Biomolecular recognition usually leads to the formation of binding complexes, often accompanied by large-scale conformational changes. This process is fundamental to biological functions at the molecular and cellular levels. Uncovering the physical mechanisms of biomolecular recognition and quantifying the key biomolecular interactions are vital to understand these functions. The recently developed energy landscape theory has been successful in quantifying recognition processes and revealing the underlying mechanisms. Recent studies have shown that in addition to affinity, specificity is also crucial for biomolecular recognition. The proposed physical concept of intrinsic specificity based on the underlying energy landscape theory provides a practical way to quantify the specificity. Optimization of affinity and specificity can be adopted as a principle to guide the evolution and design of molecular recognition. This approach can also be used in practice for drug discovery using multidimensional screening to identify lead compounds. The energy landscape topography of molecular recognition is important for revealing the underlying flexible binding or binding-folding mechanisms. In this review, we first introduce the energy landscape theory for molecular recognition and then address four critical issues related to biomolecular recognition and conformational dynamics: (1) specificity quantification of molecular recognition; (2) evolution and design in molecular recognition; (3) flexible molecular recognition; (4) chromosome structural dynamics. The results described here and the discussions of the insights gained from the energy landscape topography can provide valuable guidance for further computational and experimental investigations of biomolecular recognition and conformational dynamics.

Thymopentin treatment of murine premature ovarian failure via attenuation of immune cell activity and promotion of the BMP4/Smad9 signalling pathway

Premature ovarian failure (POF) is a typical form of pathological aging with complex pathogenesis and no effective treatment. Meanwhile, recent studies have reported that a high-fat and high-sugar (HFHS) diet adversely affects ovarian function and ovum quality. Here, we investigated the therapeutic effect of thymopentin (TP-5) as a treatment for murine POF derived from HFHS and its target. Pathological examination and hormone assays confirmed that TP-5 significantly improved murine POF symptoms. And, TP-5 could reduce oxidative stress injury and blood lipids in the murine POF derived from HFHS. Flow cytometry and qPCR results suggested that TP-5 attenuated activation of CD3+ T cells and type I macrophages. RNA-Seq results indicated somedifferences in gene transcription between the TP-5 intervention group and the control group. KEGG analysis indicated that the expression of genes involved in the mTOR signaling pathway was the most significantly different between the two groups. Additionally, compared with the control groups, the expression levels of interleukin, NFκB, and TNF families of genes were significantly downregulated in the POF+TP-5 group, whereas expression of the TGFβ/Smad9 genes was significantly upregulated. Finally, immunofluorescence staining and qPCR confirmed that TP-5 promoted the polarization of Mø2 cells in the ovary by activating the expression of the BMP4/Smad9 signalling pathway. Thus, our study confirmed that TP-5 has a significant therapeutic effect on POF by upregulating BMP4/Smad9 signalling pathway so as to promote the balance and polarization of immune cell and reducing the release of inflammatory factors and reduce lipid oxidative stress injury.

Thymopentin alleviates premature ovarian failure in mice by activating YY2/Lin28A and inhibiting the expression of let-7 family microRNAs

OBJECTIVE

Thymopentin (5TP) significantly improved typical murine premature ovarian failure (POF) symptoms induced by a high-fat and high-sugar (HFHS) diet. However, its effect and mechanism remain unclear.

MATERIALS AND METHODS

RNA-Seq was used to detect the differentially expressed genes among each group. HFHS-induced POF mouse model was generated and injected with siRNA using Poly (lactic-co-glycolic acid) (PLGA) as a carrier.

RESULTS

RNA-Seq suggested that 5TP promoted the expression of Yin Yang 2 (YY2) in mouse ovarian granulosa cell (mOGC) of HFHS-POF mice. Luciferase reporter assay indicated that 5TP promoted the binding of YY2 to the specific sequence C(C/T)AT(G/C)(G/T) on the Lin28A promoter and promoted Lin28A transcription and expression. We continuously injected PLGA-cross-linked siRNA nanoparticles targeting YY2 into HFHS-POF mice (siYY2@PLGA), which significantly reduced the therapeutic effect of 5TP. siYY2@PLGA injection also significantly attenuated the upregulation of Lin28a expression in mOGCs induced by 5TP and enhanced the expression of let-7 family microRNAs, thereby inhibiting the proliferation and division of mOGCs. qPCR results showed that there was a significant difference in the expression levels of exosome-derived Yy2 mRNAs between POF patients and normal women, and that there was a specific correlation between the expression level of exosome-derived Yy2 and the peripheral concentrations of the blood hormones pregnenolone, progesterone and oestradiol.

CONCLUSIONS

Thymopentin promotes the transcriptional activation of Lin28A via stimulating transcription factor YY2 expression, inhibits the activity of let-7 family microRNAs and alleviates the ageing of ovarian granulosa cells, ultimately achieving a therapeutic effect on POF in mice.

Therapeutic peptides for the treatment of systemic lupus erythematosus: a place in therapy

INTRODUCTION

Studies in vitro and in vivo have identified several peptides that are potentially useful in treating systemic lupus erythematosus (SLE). The rationale for their use lies in the cost-effective production, high potency, target selectivity, low toxicity, and a peculiar mechanism of action that is mainly based on the induction of immune tolerance. Three therapeutic peptides have entered clinical development, but they have yielded disappointing results. However, some subsets of patients, such as those with the positivity of anti-dsDNA antibodies, appear more likely to respond to these medications.

AREAS COVERED

This review evaluates the potential use of therapeutic peptides for SLE and gives an opinion on how they may offer advantages for SLE treatment.

EXPERT OPINION

Given their acceptable safety profile, therapeutic peptides could be added to agents traditionally used to treat SLE and this may offer a synergistic and drug-sparing effect, especially in selected patient populations. Moreover, they could temporarily be utilized to manage SLE flares, or be administered as a vaccine in subjects at risk. Efforts to ameliorate bioavailability, increase the half-life and prevent immunogenicity are ongoing. The formulation of hybrid compounds, like peptibodies or peptidomimetic small molecules, is expected to yield renewed treatments with a better pharmacologic profile and increased efficacy.

Effect of immune modulation therapy on cardiac function and T-bet/GATA-3 gene expression in aging male patients with chronic cardiac insufficiency

Aim: The aim of this study was to explore the role of immune modulation therapy in regulating the imbalance of Th1/Th2, serum IFN-γ, IL-4 and the T-cell-specific transcription factors T-bet/GATA-3 in peripheral blood in aging male patients with chronic cardiac insufficiency (CCI). Patients & methods: In total, 156 participants were divided into three groups: the CCI intervention group, which received regular therapy and thymopetidum (20 mg intramuscular injection, once every other day for 3 months; n = 70), the CCI control group, which received regular therapy (n = 56) and 50 healthy individuals older than 57 years of age, who served as normal controls. Results: Before therapy, in comparison with the control group, levels of left ventricular end diastolic diameter, NT-proBNP, C-reactive protein (CRP), Th1, Th1/Th2, IFN-γ, and T-bet mRNA and T-bet/GATA-3 mRNA all increased, and the level of left ventricular ejection fraction (LVEF), 6MWT, Th2, IL-4, and GATA-3 mRNA also decreased in both the CCI intervention and control groups. Linear correlation analysis indicated that LVEF was inversely correlated with serum NT-proBNP, CRP, Th1/Th2, IFN-γ and T-bet mRNA/GATA-3 mRNA, and was positively correlated with plasma IL-4. After 3 months of therapy, levels of left ventricular end diastolic diameter, NT-proBNP, CRP, Th1, Th1/Th2, IFN-γ, T-bet mRNA and T-bet/GATA-3 mRNA decreased in the two CCI subgroups, but levels in the CCI intervention group were lower in comparison to the control group. Levels of LVEF, 6MWT, Th2 and GATA-3 mRNA increased in the two CCI subgroups, while levels in the CCI intervention group were higher in comparison with the control group. Plasma levels of IL-4 showed no change after treatment. Conclusion: Immune modulation improved cardiac function of CCI patients and was associated with amelioration of T-helper superficial transcription factor polarization and its related cytokine imbalance. Immune modulation might be a new treatment strategy for aging CCI patients.

Affinity and specificity of levamlodipine-human serum albumin interactions: insights into its carrier function

The affinity and specificity of drugs with human serum albumin (HSA) are crucial factors influencing the bioactivity of drugs. To gain insight into the carrier function of HSA, the binding of levamlodipine with HSA has been investigated as a model system by a combined experimental and theoretical/computational approach. The fluorescence properties of HSA and the binding parameters of levamlodipine indicate that the binding is characterized by one binding site with static quenching mechanism, which is related to the energy transfer. As indicated by the thermodynamic analysis, hydrophobic interaction is the predominant force in levamlodipine-HSA complex, which is in agreement with the computational results. And the hydrogen bonds can be confirmed by computational approach between levamlodipine and HSA. Compared to predicted binding energies and binding energy spectra at seven sites on HSA, levamlodipine binding HSA at site I has a high affinity regime and the highest specificity characterized by the largest intrinsic specificity ratio (ISR). The binding characteristics at site I guarantee that drugs can be carried and released from HSA to carry out their specific bioactivity. Our concept and quantification of specificity is general and can be applied to other drug-target binding as well as molecular recognition of peptide-protein, protein-protein, and protein-DNA interactions.