Azobenzene-Based Linker Strategy for Selective Activation of Antibody-Drug Conjugates.

Existing antibody-drug conjugate (ADC) linkers, whether cleavable or non-cleavable, are designed to release highly toxic payloads or payload derivatives upon internalisation of the ADCs into cells. However, clinical studies have shown that only <1 % of the dosed ADCs accumulate in tumour cells. The remaining >99 % of ADCs are nonspecifically distributed in healthy tissue cells, thus inevitably leading to off-target toxicity. Herein, we describe an intelligent tumour-specific linker strategy to address these limitations. A tumour-specific linker is constructed by introducing a hypoxia-activated azobenzene group as a toxicity controller. We show that this azobenzene-based linker is non-cleavable in healthy tissues (O2 >10 %), and the corresponding payload derivative, cysteine-appended azobenzene-linker-monomethyl auristatin E (MMAE), can serve as a safe prodrug to mask the toxicity of MMAE (switched off). Upon exposure to the hypoxic tumour microenvironment (O2<1 %), this linker is cleaved to release MMAE and fully restores the high cytotoxicity of the ADC (switched on). Notably, the azobenzene linker-containing ADC exhibits satisfactory antitumour efficacy in vivo and a larger therapeutic window compared with ADCs containing traditional cleavable or non-cleavable linkers. Thus, our azobenzene-based linker sheds new light on the development of next-generation ADC linkers.

Multi-UAV Path Planning in GPS and Communication Denial Environment.

This paper proposes a feature fusion algorithm for solving the path planning problem of multiple unmanned aerial vehicles (UAVs) using GPS and communication denial conditions. Due to the blockage of GPS and communication, UAVs cannot obtain the precise position of a target, which leads to the failure of path planning algorithms. This paper proposes a feature fusion proximal policy optimization (FF-PPO) algorithm based on deep reinforcement learning (DRL); the algorithm can fuse image recognition information with the original image, realizing the multi-UAV path planning algorithm without an accurate target location. In addition, the FF-PPO algorithm adopts an independent policy for multi-UAV communication denial environments, which enables the distributed control of UAVs such that multi-UAVs can realize the cooperative path planning task without communication. The success rate of our proposed algorithm can reach more than 90% in the multi-UAV cooperative path planning task. Finally, the feasibility of the algorithm is verified by simulations and hardware.

A Robust Planar Marker-Based Visual SLAM.

Many visual SLAM systems are generally solved using natural landmarks or optical flow. However, due to textureless areas, illumination change or motion blur, they often acquire poor camera poses or even fail to track. Additionally, they cannot obtain camera poses with a metric scale in the monocular case. In some cases (such as when calibrating the extrinsic parameters of camera-IMU), we prefer to sacrifice the flexibility of such methods to improve accuracy and robustness by using artificial landmarks. This paper proposes enhancements to the traditional SPM-SLAM, which is a system that aims to build a map of markers and simultaneously localize the camera pose. By placing the markers in the surrounding environment, the system can run stably and obtain accurate camera poses. To improve robustness and accuracy in the case of rotational movements, we improve the initialization, keyframes insertion and relocalization. Additionally, we propose a novel method to estimate marker poses from a set of images to solve the problem of planar-marker pose ambiguity. Compared with the state-of-art, the experiments show that our system achieves better accuracy in most public sequences and is more robust than SPM-SLAM under rotational movements. Finally, the open-source code is publicly available and can be found at GitHub.

Structure-activity relationship and biological evaluation of 12 N-substituted aloperine derivatives as PD-L1 down-regulatory agents through proteasome pathway.

Twenty-nine 12 N-substituted aloperine derivatives were synthesized and screened for suppression on PD-L1 expression in H460 cells, as a continuation of our work. Systematic structural modifications led to the identification of compound 6b as the most active PD-L1 modulator. Compound 6b could significantly down-regulate both constitutive and inductive PD-L1 expression in NSCLC cells, and successively enhance the cytotoxicity of co-cultured T cells against tumor cells at the concentration of 20 µM. Also, it exhibited a moderate in vivo anticancer efficacy against Lewis tumor xenograft with a stable PK and safety profile. The mechanism study indicated that 6b mediated the degradation of PD-L1 through a proteasome pathway, rather than a lysosome route. These results provided the powerful information for cancer immunotherapy of aloperine derivatives with unique endocyclic skeleton by targeting PD-L1 to activate immune cells to kill cancer cells.

MPB, a novel berberine derivative, enhances lysosomal and bactericidal properties via TGF-ß-activated kinase 1-dependent activation of the transcription factor EB.

Lysosome has a crucial role in clearance of endocytosed pathogens from the cell. Small molecules that can boost lysosome function and bactericidal ability to cope with subsequent infection are urgently needed. Here, we report that MPB, a novel berberine derivative, induced lysosome-based degradation and clearance of methicillin-resistant Staphylococcus aureus and enteroinvasive Escherichia coli in macrophages. MPB caused nuclear translocation of transcription factor EB (TFEB), which boosted expression of lysosome genes. TFEB silencing repressed the MPB-mediated enhancements in degradation and bacterial eradication. MPB switched on TFEB nuclear translocation by coupling 2 parallel signaling pathways. MPB-triggered JNK activation led to 14-3-3δ being released from TFEB, which, in turn, caused TFEB nuclear translocation. In addition, MPB induced AMPK activation and subsequent inhibition of mechanistic target of rapamycin activity, which also contributed to TFEB nuclear translocation. Importantly, genetical or pharmaceutical inhibition of TGF-ß-activated kinase 1 (TAK1) reduced MPB action remarkably. MPB acted through TAK1 at lysine 158 to activate JNK and AMPK and, thus, induced TFEB-dependent bactericidal activity in macrophages. Therefore, our study reveals a novel mechanism by which MPB controls JNK and AMPK phosphorylation cascades to activate lysosomal function and bactericidal activity via TAK1 K158-dependent manner, which may offer insight into novel therapeutic strategies to control bacterial infection.-Liu, X., Zhang, N., Liu, Y., Liu, L., Zeng, Q., Yin, M., Wang, Y., Song, D., Deng, H. MPB, a novel berberine derivative, enhances lysosomal and bactericidal properties via TGF-ß-activated kinase 1-dependent activation of the transcription factor EB.

Synthesis and Biological Evaluation of Fangchinoline Derivatives as Anti-Inflammatory Agents through Inactivation of Inflammasome.

Twenty eight 7-substitued fangchinoline analogues, of which twenty two were novel, were synthesized and evaluated for their effect to inhibit lipopolysaccharide/nigericin (LPS/NIG)-induced IL-1ß release at both cell and protein levels at the concentration of 5 µM. Among them, compound 6 exhibited promising inhibitory potency against IL-ß activation with an IC50 value of 3.7 µM. Preliminary mechanism study revealed that 6 might target NLRP3 protein, and then block ASC pyroptosome formation with-NLRP3, rather than acting on the activation of the NLRP3 inflammasome (NF-κB and MAPK pathways) or caspase-1 protein. Our current study supported the potential role of compound 6 against IL-ß activation, and provided powerful information for developing fangchinoline derivatives into a novel class of anti-inflammatory agents.

Resibufogenin suppresses transforming growth factor-ß-activated kinase 1-mediated nuclear factor-κB activity through protein kinase C-dependent inhibition of glycogen synthase kinase 3.

Resibufogenin (RB), one of the major active compounds of the traditional Chinese medicine Chansu, has received considerable attention for its potency in cancer therapy. However, the anticancer effects and the underlying mechanisms of RB on pancreatic cancer remain elusive. Here, we found that RB inhibited the viability and induces caspase-dependent apoptosis in human pancreatic cancer cells Panc-1 and Aspc. Resibufogenin-induced apoptosis was through inhibition of constitutive nuclear factor-κB (NF-κB) activity and its target genes' expression, which was caused by downregulation of transforming growth factor-ß-activated kinase 1 (TAK1) levels and suppression of IκB kinase activity in Panc-1 and Aspc cells. This induction of TAK1-mediated NF-κB inactivation by RB was associated with increased glycogen synthase kinase-3 (GSK-3) phosphorylation and subsequent suppression of its activity. Moreover, RB-induced GSK-3 phosphorylation/inactivation acted through activation of protein kinase C but not Akt. Finally, RB suppressed human pancreatic tumor xenograft growth in athymic nude mice. Thus, our findings reveal a novel mechanism by which RB suppresses TAK1-mediated NF-κB activity through protein kinase C-dependent inhibition of GSK-3. Our findings provide a rationale for the potential application of RB in pancreatic cancer therapy.

Synthesis and Identification of Novel Berberine Derivatives as Potent Inhibitors against TNF-α-Induced NF-κB Activation.

Twenty-three new berberine (BBR) analogues defined on substituents of ring D were synthesized and evaluated for their activity for suppression of tumor necrosis factor (TNF)-α-induced nuclear factor (NF)-κB activation. Structure-activity relationship (SAR) analysis indicated that suitable tertiary/quaternary carbon substitutions at the 9-position or rigid fragment at position 10 might be beneficial for enhancing their anti-inflammatory potency. Among them, compounds 2d, 2e, 2i and 2j exhibited satisfactory inhibitory potency against NF-κB activation, with an inhibitory rate of around 90% (5 µM), much better than BBR. A preliminary mechanism study revealed that all of them could inhibit TNF-α-induced NF-κB activation via impairing IκB kinase (IKK) phosphorylation as well as cytokines interleukin (IL)-6 and IL-8 induced by TNF-α. Therefore, the results provided powerful information on further structural modifications and development of BBR derivatives into a new class of anti-inflammatory candidates for the treatment of inflammatory diseases.

A novel predictive model for optimizing diabetes screening in older adults.

INTRODUCTION: The fasting blood glucose test is widely used for diabetes screening. However, it may fail to detect early-stage diabetes characterized by elevated postprandial glucose levels. Hence, we developed and internally validated a nomogram to predict the diabetes risk in older adults with normal fasting glucose levels. MATERIALS AND METHODS: This study enrolled 2,235 older adults, dividing them into a Training Set (n = 1,564) and a Validation Set (n = 671) based on a 7:3 ratio. We employed the least absolute shrinkage and selection operator regression to identify predictors for constructing the nomogram. Calibration and discrimination were employed to assess the nomogram's performance, while its clinical utility was evaluated through decision curve analysis. RESULTS: Nine key variables were identified as significant factors: age, gender, body mass index, fasting blood glucose, triglycerides, alanine aminotransferase, the ratio of alanine aminotransferase to aspartate aminotransferase, blood urea nitrogen, and hemoglobin. The nomogram demonstrated good discrimination, with an area under the receiver operating characteristic curve of 0.824 in the Training Set and 0.809 in the Validation Set. Calibration curves for both sets confirmed the model's accuracy in estimating the actual diabetes risk. Decision curve analysis highlighted the model's clinical utility. CONCLUSIONS: We provided a dynamic nomogram for identifying older adults at risk of diabetes, potentially enhancing the efficiency of diabetes screening in primary healthcare units.

Erratum: Author correction to 'Discovery and identification of EIF2AK2 as a direct key target of berberine for anti-inflammatory effects' [Acta Pharmaceutica Sinica B 13 (2023) 2138-2151].

[This corrects the article DOI: 10.1016/j.apsb.2022.12.009.].

S632A3, a new glutarimide antibiotic, suppresses lipopolysaccharide-induced pro-inflammatory responses via inhibiting the activation of glycogen synthase kinase 3ß.

Inflammatory mediators including inducible nitric oxide (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6) contribute to the course of a variety of inflammatory diseases. S632A3 is a new member of the glutarimide antibiotics isolated from a cultured broth of Streptomyces hygroscopicus S632 with a potent NF-κB inhibitory activity. In the present study, we investigated the anti-inflammatory effects and the underlying molecular mechanism of S632A3 on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. S632A3 concentration-dependently inhibited LPS-induced NO and prostaglandin E(2) (PGE(2)) production through the suppression of iNOS and COX-2 at gene transcription levels. In addition, S632A3 suppressed NF-κB-dependent inflammatory responses by inhibiting the activation of glycogen synthase kinase 3ß (GSK-3ß), while the activation of IκB kinase (IKK) complex was unaffected. S632A3 suppressed NF-κB activity by differentially affecting the CREB (cAMP response element-binding protein) and NF-κB p65 interacting with the coactivator CBP (CREB binding protein). S632A3 also inhibited GSK-3ß-elicited iNOS and COX-2 expression. Moreover, S632A3 was shown to inhibit the activation of ASK1 (Apoptosis-signal regulating kinase 1) and p38 mitogen-activated protein kinase, therefore attenuated the LPS-induced NF-κB activity in macrophages. Furthermore, S632A3 significantly reduced the pro-inflammatory cytokines TNF-α and IL-6 production while increased the anti-inflammatory cytokine IL-10 production in LPS-stimulated RAW264.7 cells. Our study thus provides a molecular mechanism by which S632A3 inhibited LPS-induced pro-inflammatory response in macrophages through interfering with the activation of GSK-3ß and ASK1-p38 signaling.

[S632A3 promotes LPS-induced IFN-beta production through inhibiting the activation of GSK-3beta].

LPS stimulation of macrophages production of IFN-beta plays a key role in innate immunity defending the microbial invasion. In this study, the effect of S632A3 promoting LPS-induced IFN-beta production and the underlying mechanism were investigated, mRNA level was measured by real-time PCR, cytokine production was determined by ELISA, GSK-3beta activity was investigated by kinase assay, protein phosphorylation and expression were evaluated by Western blotting. The results revealed that S632A3 significantly augmented IFN-beta production by LPS-stimulated macrophages. S632A3 inhibition of the activation of GSK-3beta, reduced the threonine 239 phosphorylation of transcription factor c-Jun but increased the total level of c-Jun in LPS-stimulated macrophages. Moreover, small interfering RNA-mediated knockdown of c-Jun level abrogated the ability of S632A3 to augment IFN-beta. The study thus demonstrates S632A3 being a new anti-inflammation lead compound and provides a molecular mechanism by which S632A3 promoted LPS-induced IFN-beta production in macrophages through inhibiting the activation of GSK-3beta.

Association between circadian body temperature rhythm during the first 24 hours of ICU stay and 28-day mortality in elderly critically ill patients: A retrospective cohort study.

Disrupted circadian temperature rhythm is commonly observed in elderly patients in the intensive care unit (ICU), but the association between circadian temperature rhythm and mortality in elderly patients is unclear. Adult patients with a relatively complete record of body temperature (BT) during the first 24 hours of ICU stay in the Multi-parameter Intelligent Monitoring in Intensive Care IV (MIMIC-IV) database were included in this retrospective cohort study. The circadian rhythm of body temperature was blunted as a ratio of the maximum BT between 12:00 and 24:00 divided by the minimum BT between 0:00 and 12:00, and we defined it as BT fluctuation ratio. The associations of BT fluctuation ratio with 28-day mortality were assessed separately using Cox proportional hazards model in elderly patients and non-elderly patients. The overall cohort comprised 12 767 patients. After adjusting for covariates, the analysis showed that the BT fluctuation ratio (%) was significantly associated with mortality at 28 days in total patients (hazard ratio: 1.044; 95% CI 1.001-1.088; P = 0.042), and still significantly in elderly patients (hazard ratio 1.055, 95% CI as 1.004-1.109, p = 0.035), but not significantly in non-elderly patients. The implementation of restricted cubic splines demonstrated a nonlinear correlation between the ratio of BT fluctuation and the hazard ratio of 28-day mortality, indicating that increased diurnal temperature fluctuations are linked to elevated risk of mortality. This study revealed that the augmented amplitude of the circadian rhythm of body temperature in the elderly patients constitutes a risk factor for the rise of 28-day mortality. Additionally, the circadian body temperature rhythm may facilitate the early detection of critically ill elderly patients.

Raddeanin A Enhances Mitochondrial DNA-cGAS/STING Axis-Mediated Antitumor Immunity by Targeting Transactive Responsive DNA-Binding Protein 43.

Immune checkpoint therapies (ICT) have achieved unprecedented efficacy in multiple cancer treatments, but are still limited by low clinical response rates. Identification of immunogenic cell death (ICD)-inducing drugs that can induce tumor cell immunogenicity and reprogram the tumor microenvironment is an attractive approach to enhance antitumor immunity. In the present study, Raddeanin A (RA), an oleanane class triterpenoid saponin isolated from Anemone raddeana Regel, is uncovered as a potent ICD inducer through an ICD reporter assay combined with a T cell activation assay. RA significantly increases high-mobility group box 1 release in tumor cells and promotes dendritic cell (DC) maturation and CD8+ T cell activation for tumor control. Mechanistically, RA directly binds to transactive responsive DNA-binding protein 43 (TDP-43) and induces TDP-43 localization to mitochondria and mtDNA leakage, leading to cyclic GMP-AMP synthase/stimulator of interferon gene-dependent upregulation of nuclear factor κB and type I interferon signaling, thereby potentiating the DC-mediated antigen cross-presentation and T cell activation. Moreover, combining RA with anti-programmed death 1 antibody effectively enhances the efficacy of ICT in animals. These findings highlight the importance of TDP-43 in ICD drug-induced antitumor immunity and reveal a potential chemo-immunotherapeutic role of RA in enhancing the efficacy of cancer immunotherapy.

U-shaped association between serum triglyceride levels and mortality among septic patients: An analysis based on the MIMIC-IV database.

BACKGROUND: Sepsis is characterized by upregulated lipolysis in adipose tissue and a high blood triglyceride (TG) level. It is still debated whether serum TG level is related to mortality in septic patients. The aim of this study is to investigate the association between serum TG level and mortality in septic patients admitted to the intensive care unit (ICU). METHODS: Data from adult septic patients (≥18 years) admitted to the ICU for the first time were obtained from the Multiparameter Intelligent Monitoring in Intensive Care IV (MIMIC-IV) database. The patients' serum TG levels that were measured within the first week after ICU admission were extracted for statistical analysis. The endpoints were 28-day, ICU and in-hospital mortality. RESULTS: A total of 2,782 septic patients were included. Univariate analysis indicated that the relationship between serum TG levels and the risk of mortality was significantly nonlinear. Both the Lowess smoothing technique and restricted cubic spline analyses revealed a U-shaped association between serum TG levels and mortality among septic patients. The lowest mortality rate was associated with a serum TG level of 300-500 mg/dL. Using 300∼500 mg/dL as the reference range, we found that both hypo-TG (<300 mg/dL) and hyper-TG (≥500 mg/dL) were associated with increased mortality. The result was further adjusted by Cox regression with and without the inclusion of some differential covariates. CONCLUSIONS: There was a U-shaped association between serum TG and mortality in septic ICU patients. The optimal concentration of serum TG levels in septic ICU patients is 300-500 mg/dL.

USP2 promotes tumor immune evasion via deubiquitination and stabilization of PD-L1.

The abnormal upregulation of programmed death ligand-1 (PD-L1) on tumor cells impedes T-cell mediated cytotoxicity through PD-1 engagement, and further exploring the mechanisms regulation of PD-L1 in cancers may enhance the clinical efficacy of PD-L1 blockade. Here, using single-guide RNAs (sgRNAs) screening system, we identify ubiquitin-specific processing protease 2 (USP2) as a novel regulator of PD-L1 stabilization for tumor immune evasion. USP2 directly interacts with and increases PD-L1 abundance in colorectal and prostate cancer cells. Our results show that Thr288, Arg292 and Asp293 at USP2 control its binding to PD-L1 through deconjugating the K48-linked polyubiquitination at lysine 270 of PD-L1. Depletion of USP2 causes endoplasmic reticulum (ER)-associated degradation of PD-L1, thus attenuates PD-L1/PD-1 interaction and sensitizes cancer cells to T cell-mediated killing. Meanwhile, USP2 ablation-induced PD-L1 clearance enhances antitumor immunity in mice via increasing CD8+ T cells infiltration and reducing immunosuppressive infiltration of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), whereas PD-L1 overexpression reverses the tumor growth suppression by USP2 silencing. USP2-depletion combination with anti-PD-1 also exhibits a synergistic anti-tumor effect. Furthermore, analysis of clinical tissue samples indicates that USP2 is positively associated with PD-L1 expression in cancer. Collectively, our data reveal a crucial role of USP2 for controlling PD-L1 stabilization in tumor cells, and highlight USP2 as a potential therapeutic target for cancer immunotherapy.

Discovery and development of palmatine analogues as anti-NASH agents by activating farnesoid X receptor (FXR).

Sixty-one palmatine (PMT) derivatives, of which twenty-eight were new, were synthesized and evaluated for their anti-fibrogenic activities via collagen type I α 1 (COL1A1)-promoter based luciferase model in LX-2 cells, taking 2,3,10-trimethoxy-9-p-isopropyloxyprotopalmatine bromide (1) as the lead. Among them, compound 3a exerted the highest potency with the IC50 value of 8.19 µmol/L and SI value of 8.59, and reduced the expressions of multiple fibrogenic biomarkers, including COL1A1, TGF-ß1, α-SMA and TIMP1 in a dose-dependent manner. In addition, it significantly reduced liver steatosis and inflammation, and especially attenuated the degree of liver fibrosis in choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD)-induced NASH mice model in vivo. Mechanism study indicated that it significantly ameliorated liver injury by activating farnesoid X receptor (FXR). BDL-induced fibrosis rats model further verified its liver-protective and anti-fibrosis activities. Therefore, PMT derivatives constituted a new family of non-steroidal FXR agonists as anti-NASH candidates, with the advantage of good safety profile, and are worthy for further investigation.

Discovery and identification of EIF2AK2 as a direct key target of berberine for anti-inflammatory effects.

Using chemoproteomic techniques, we first identified EIF2AK2, eEF1A1, PRDX3 and VPS4B as direct targets of berberine (BBR) for its synergistically anti-inflammatory effects. Of them, BBR has the strongest affinity with EIF2AK2 via two ionic bonds, and regulates several key inflammatory pathways through EIF2AK2, indicating the dominant role of EIF2AK2. Also, BBR could subtly inhibit the dimerization of EIF2AK2, rather than its enzyme activity, to selectively modulate its downstream pathways including JNK, NF-κB, AKT and NLRP3, with an advantage of good safety profile. In EIF2AK2 gene knockdown mice, the inhibitory IL-1ß, IL-6, IL-18 and TNF-α secretion of BBR was obviously attenuated, confirming an EIF2AK2-dependent anti-inflammatory efficacy. The results highlight the BBR's network mechanism on anti-inflammatory effects in which EIF2AK2 is a key target, and inhibition of EIF2AK2 dimerization has a potential to be a therapeutic strategy against inflammation-related disorders.

Evaluation and mechanism study of Pien Tze Huang against EV-A71 infection.

Hand, foot, and mouth disease (HFMD) caused by enterovirus A71 (EV-A71) infection, currently lacks specific preventive and therapeutic interventions. Here, we demonstrated that Pien Tze Huang (PZH) could dose-dependently inhibit EV-A71 replication at the cellular level, resulting in significant reductions in EV-A71 virus protein 1 (VP1) expression and viral yields in Vero and human rhabdomyosarcoma cells. More importantly, we confirmed that PZH could protect mice from EV-A71 infection for the first time, with Ribavirin serving as a positive control. PZH treatment reduced EV-A71 VP1 protein expression, viral yields in infected muscles, and improved muscle pathology. Additionally, we conducted a preliminary mechanism study using quantitative proteomics. The results suggested that the suppression of the PI3K/AKT/mTOR and NF-κB signaling pathways may contribute to the anti-EV-A71 activity of PZH. These findings provide strong evidence supporting the potential therapeutic application of PZH for EV-A71 infection management.