Molecular chaperone system, which mainly consist of heat shock proteins family and their cochaperones, is crucial for maintaining proteostasis in life. It assists in folding, maturation and ubiquitin-proteasome-mediated degradation of proteins, thus to play a key role in cell proliferation and apoptosis. Functional disorder of molecular chaperone system is highly relevant to occurrence and development of multiple diseases including cancers, autoimmune disease/inflammatory, infective diseases, neurodegenerative disease, etc. Therefore, molecular chaperone system has long been regarded as potential drug targets. In this review, we outline the progress in the design of small molecules targeting molecular chaperone system and analyze the features of small molecules with different mechanisms. Finally, we put forward expects about potential development directions for future drug design in this field.

Immunotherapy has become another effective tumor treatment after surgical resection, chemotherapy, radiotherapy and targeted therapy. However, due to the low immunogenicity of tumor cells and immunosuppressive tumor microenvironment, antigen-presenting cells inefficiently process and present tumor antigens, thus leading to insufficient activation of cytotoxic T lymphocytes and tumor infiltration, which significantly affects the effectiveness of tumor immunotherapy. In recent years, it has been demonstrated that multiple metal ions exhibit distinguished modulatory effects in activating innate immune stimulation and conquering acquired immune tolerance. Based on this, scientists have designed a series of nano-adjuvant delivery systems with metal ions or metal nanoparticles to enhance the targeted accumulation of metal ions in tumor tissues or lymphoid organs for efficiently inducing immunogenic cell death or directly activating antigen-presenting cells to initiate anti-tumor specific immune response. This review briefly outlines the role of various metal ions in anti-tumor immunomodulation, summarizes the research progress in using metal nanoadjuvant delivery systems to achieve efficient anti-tumor immunotherapy, and provides foresight on the main challenges and potential directions in this field.

γ-Aminobutyric acid (GABA) is a crucial inhibitory neurotransmitter found in various cells in the human body. While the GABAergic system is typically associated with the nervous system, recent research has revealed that immune cells and tumor cells also express components of this system. In the tumor microenvironment (TME), GABA is secreted to act extracellularly on other cells. GABA is metabolized via the GABA shunt and is involved in the tricarboxylic acid (TCA) cycle by generating succinate, which can provide energy for tumor cells. Activation of GABA receptors (GABARs) is a major pathway through which GABA participates in the regulation of antitumor immune responses. The activation of GABA type A receptors (GABA_ARs) can inhibit the activation and proliferation of T cells, elicit anti-inflammatory macrophages, and promote tumor cell growth and migration, while activation of GABA type B receptors (GABA_BRs) is generally considered to inhibit cancer cell migration and induce cancer cell apoptosis. In general, receptor activation inhibits immune cells, but the effect on tumor cells varies. Additionally, the downregulation of the expression levels of GABA transporters (GATs) is involved in tumor progression. Although antagonists of GABA metabolism and drugs that act on GABA receptors are considered therapeutic drugs for tumors, there have been few clinical studies conducted on them.

To address the continuous emergence of drug-resistant strains of viruses and the outbreaks of novel virus infections, developing new antiviral drugs based on novel strategies has become an important and urgent research topic. In recent years, the rapidly developing multi-specific binding strategy has become a focus and been widely applied in antiviral. This review summarizes the recent progress of the multi-specific binding strategy in the antiviral field from the perspective of medicinal chemistry and discusses existing challenges as well as future opportunities for antiviral drug discovery.

C17 is an orally available anti-tumor compound inhibiting cancer stem cell (CSC). In this study, a stable, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established and validated, and was further applied to a pharmacokinetic study in nude mice receiving C17 by gavage. Using propranolol as the internal standard, the plasma samples were pre-treated by precipitation with methanol and analyzed on an Intersil C8-3 column (100 mm × 2.1 mm, 3 μm), and gradient elution was performed with a mobile phase consisting of 0.1% formic acid aqueous and solution mixed up by 90% isopropanol and 10% acetonitrile. The analyte was detected by a triple quadrupole tandem mass spectrometer, and multiple reaction monitoring was employed to select C17 at m/z 439.3/247.1 and propranolol at m/z 260.2/116.2 in the positive ion mode. The calibration curves were linear (r > 0.995) over the range of 5-800 ng·mL^-1. The intra- and inter-day precisions and accuracies were 7.42%-13.22% and -8.99%-8.81% respectively. The method was successfully applied to a PK study in nude mice administered with a single oral dose of 50 mg·kg^-1 C17, and the PK data were analyzed with non-linear mixed effect model (NONMEM). Two separated absorption peaks were found in the PK curve of C17, and a two-compartment model with two sequential first-order absorption rate was utilized to describe the PK properties of C17, and the model could provide insights into the physiological process and exposure of C17 in nude mice. All animal experiments were in strict accordance with the regulations of the Biomedical Ethics Committee of Peking University.

Krüppel-like transcription factor 2 (KLF2) plays a key regulatory role in endothelial inflammation, thrombosis, angiogenesis and macrophage inflammation and polarization, and up-regulation of KLF2 expression has the potential to prevent and treatment atherosclerosis. In this study, trichostatin C (TSC) was obtained from the secondary metabolites of rice fermentation of Streptomyces sp. CPCC 203909 as a KLF2 up-regulator by using a high throughput screening model based on a KLF2 promoter luciferase reporter assay. TSC significantly inhibited the adhesion of tumor necrosis factor-α (TNFα) induced monocytes (THP-1) to human umbilical vein endothelial cells (HUVECs). Western blot results showed that TSC decreased TNFα induced the protein expression increase of vascular cell adhesion molecule-1 (VCAM-1), and thereby inhibited endothelial inflammation. The results of histone deacetylase (HDAC) overexpression and molecular docking experiments showed that TSC upregulated the expression of KLF2 by inhibiting subtypes of HDAC 4/5/7. In conclusion, this study suggests that TSC up-regulates the expression of KLF2 through inhibiting HDAC 4/5/7 and thus inhibits TNFα induced endothelial inflammation, and it has the potential to prevent and treat atherosclerosis.

Proteolysis targeting chimeras (PROTACs) is an innovative technique in targeted protein degradation. PROTACs is a heterobifunctional molecule which can bind to the E3 ligase and target protein to form a ubiquitination complex, resulting in the ubiquitin-proteasome system dependent degradation of target protein. PROTACs has been regarded as the promising method in drug discovery campaign, for its high commonality, potent degradation activity and unique selectivity profile. However, the catalytic mechanism also induces the uncontrollable protein degradation risk. Controllable PROTACs contain the responsive element in the molecular entity. In certain conditions, the element can be triggered to activate or terminate the degradation event. In this review, we will briefly summarize the strategies in controllable PROTACs and describe the representative examples according to the responsive mechanism. We hope this review could provide some insight into the further development of controllable PROTACs.

Polysaccharides and free monosaccharides are important active components in Cistanches Herba, which have functions of anti-aging and immunological activity regulation. The study of monosaccharide composition in polysaccharide and free monosaccharide can lay a foundation for the study of primary structure, spatial structure of Cistanche polysaccharide and biological activity of Cistanches Herba. In this study, a method of water extraction and alcohol precipitation was used to extract Cistanche polysaccharide. Trifluoroacetic acid was selected as the hydrolytic acid for polysaccharide hydrolysis. An orthogonal experimental method is established. Three levels of acid concentration, hydrolysis temperature and hydrolysis time were selected to investigate the optimal hydrolysis condition. The optimal hydrolysis condition was 0.08 mol·L^-1 trifluoroacetic acid hydrolysis at 100 ℃ for 3 h. The free monosaccharides of Cistanches Herba were extracted by water extraction. The established ion chromatogram integrated pulsed amperometry method can efficiently separate 11 monosaccharides in a short time. The method has good repeatability and high sensitivity, methodological experiment results meet the requirements of quantitative determination. It can accurately determine the monosaccharide composition of Cistanche polysaccharide and free monosaccharide content. Ion chromatography does not require derivatization operation and the pre-treatment steps are simple. This method can measure fructose, but PMP derivation-HPLC method can't. The monosaccharide composition of Cistanche polysaccharide include fucose, arabinose, rhamnose-galactose, glucose, xylose, mannose, fructose, ribose and glucuronic acid, among which the contents of glucose and fructose are relatively high. The free monosaccharides in the water extract of Cistanches Herba include glucose, fructose and mannose.

Puromycin-sensitive aminopeptidase (PSAP) belongs to the M1 family of aminopeptidases, characterized by the N-terminal substrate binding sequence GAMEN, the enzyme activity center HEXXH(X)₁₈E motif, and the C-terminal ERAP-1-like superfamily structural domain. Encoded by the gene NPEPPS located at 17q21.32, PSAP consists of 919 amino acids and is widely distributed throughout the human body, with the highest expression in the brain, followed by the heart and skeletal muscle. It is also found in the liver, renal tubular epithelium, small intestine, large intestine epithelium, and gastric epithelial cells. PSAP primarily relies on its aminopeptidase hydrolytic activity to remove toxic protein aggregates such as Tau, poly Q, and Cu, Zn-superoxide dismutase 1, making it an important factor in the development of diseases such as Alzheimer's disease, Huntington's chorea, and tumors. Existing PSAP inhibitors include bestatin, amastatin, leuhistin, actinonin, and purinomycin, some of which are already available or in clinical trials. This review provides an overview of the structural and biological functions of M1 family aminopeptidases, with a focus on PSAP, to facilitate further research and targeted drug development.

Brain delivery of drugs remains challenging due to the presence of the blood-brain barrier (BBB). With advances in nanotechnology and biotechnology, new possibilities for brain-targeted drug delivery have emerged. Biomimetic nano drug delivery systems with high brain-targeting and BBB-penetrating capabilities, along with good biocompatibility and safety, can enable 'invisible' drug delivery. In this review, five different types of biomimetic strategies are presented and their research progress in central nervous system disorders is reviewed. Finally, the challenges and future prospects for biomimetic nano drug delivery systems in intracerebral drug delivery are summarized.