Synthesis and Biological Evaluation of Novel Biased Mu-Opioid Receptor Agonists.

This study explored the potential of a series of PZM21 analogues for pain treatment. Specifically, the hydroxyphenyl ring of PZM21 was replaced with a naphthyl ring, the thienyl ring was substituted with either a phenyl ring or furan rings, and the essential dimethylamine and urea groups were retained. These compounds aimed to enhance safety and minimize the adverse effects associated with opioid drugs. The research findings suggest that compound 6a does not induce ß-arrestin recruitment at low-nanomolar concentrations but exhibits significant analgesic effects in established mouse models. Compared to morphine, 6a shows advantages in alleviating respiratory depression and minimizing physical dependence. Molecular docking studies underscore the pivotal role of the D147 amino acid residue in the analgesic mechanism of 6a. Consequently, 6a is a compelling candidate for the development of safer opioid analgesics and warrants further attention.

The Programmable Catalytic Core of 8-17 DNAzymes.

8-17 DNAzymes (8-17, 17E, Mg5, and 17EV1) are in vitro-selected catalytic DNA molecules that are capable of cleaving complementary RNAs. The conserved residues in their similar catalytic cores, together with the metal ions, were suggested to contribute to the catalytic reaction. Based on the contribution of the less conserved residues in the bulge loop residues (W12, A15, A15.0) and the internal stem, new catalytic cores of 8-17 DNAzymes were programmed. The internal stem CTC-GAG seems to be more favorable for the DNAzymes than CCG-GGC, while an extra W12.0 led to a significant loss of activity of DNAzymes, which is contrary to the positive effect of A15.0, by which a new active DNAzyme 17EM was derived. It conducts a faster reaction than 17E. It is most active in the presence of Pb2+, with the metal ion preference of Pb2+ >> Zn2+ > Mn2+ > Ca2+ ≈ Mg2+. In the Pb2+ and Zn2+-mediated reactions of 17EM and 17E, the same Na+- and pH dependence were also observed as what was observed for 17E and other 8-17 DNAzymes. Therefore, 17EM is another member of the 8-17 DNAzymes, and it could be applied as a potential biosensor for RNA and metal ions.

Dual-mode sensing strategy based on carbon dots for sensitive and selective detection of molybdate ions.

Two kinds of carbon dots with the maximum fluorescence peak of 492 nm (named as G-CDs) and 607 nm (named as R-CDs) were synthesized. In the presence of MoO42- ions, the fluorescence of R-CDs at 607 nm can be quenched, which can probably be assigned to their aggregation caused by MoO42-, while that of G-CDs at 492 nm remained unchanged. For the first time, a ratiometric fluorescence probe was developed for MoO42- ions detection. In the range 0.25 ~ 100 µM, the fluorescence ratio (F492/F607) of the probe was linearly related to MoO42- concentration, and the detection limit was 61.5 nM, which fully meets the minimum detection requirements of MoO42- ions in drinking water. On the other hand, when MoO42- was introduced, a significant fading phenomenon of R-CDs can be observed with the naked eye; thereby, the colorimetric method can also be proposed. Based on above, the ratiometric fluorometric/colorimetric dual-mode sensing method was established for MoO42- anion quantification. Compared with the traditional analysis methods, the results obtained by multimodal sensing can be mutually verified, which effectively improves the accuracy and reliability. The dual-mode assay proposed in this work provides an alternative scheme to meet the need of sensing target compounds in complex matrices.

Transformer Based Cross-Subject Mental Workload Classification Using FNIRS for Real-World Application.

Mental state monitoring is a hot topic especially in neurorehabilitation, skill training, etc, for which the functional near-infrared spectroscopy (fNIRS) has been suggested to be used, and fewer detection channels and cross-subject performance are usually required for real-world application. To this goal, we propose a transformer-based method for cross-subject mental workload classification using fewer channels of fNIRS. Firstly, the input fNIRS signals in a window are divided into patches in the temporal order and transformed into embeddings, to which a classification token and learnable position embeddings are added. Then, a transformer encoder is used to learn the long-range dependencies among the embeddings, of which the output classification token is sent to a multilayer perceptron (MLP) head. Mental workload classification results can be represented by the outputs of the MLP head. Finally, comparison experiments were conducted on the open-access fNIRS2MW dataset. The results show that, the proposed method can outperform previous methods in cross-subject classification accuracy, and relatively efficient computation can be obtained.

A novel camptothecin derivative, ZBH-01, exhibits superior antitumor efficacy than irinotecan by regulating the cell cycle.

BACKGROUND: Irinotecan (CPT-11) is a classic chemotherapeutic agent that plays an important role in the clinical treatment of metastatic colon cancer and other malignant tumors. We previously designed a series of novel irinotecan derivatives. In this study, we select one representative, ZBH-01, to investigate its sophisticated antitumor mechanism in colon tumor cells. METHODS: The cytotoxic activity of ZBH-01 on colon cancer cells was evaluate by MTT or Cell Counting Kit-8 (CCK8) assay, 3D and xenograft model. The inhibitory effect of ZBH-01 on TOP1 was detected by DNA relaxation assay and Immuno Complex of Ezyme (ICE) bioassay. The molecular mechanism of ZBH-01 was explored by Next-Generation Sequencing (NGS), bioinformatics analyses, flow cytometry, qRT-PCR, and western blot etc. RESULTS: ZBH-01 can induce obvious DNA damage and has superior antitumor activity against colon cancer cells compared to CPT-11 and SN38 (7-Ethyl-10-hydroxy camptothecin, the in vivo active form of CPT-11) both in vivo and in vitro. Its inhibitory effect on topoisomerase I (TOP1) was also comparable with these two control drugs. There are a much larger number of 842 downregulated and 927 upregulated mRNAs in ZBH-01 treatment group than that in the controls. The most significantly enriched KEGG pathways for these dysregulated mRNAs were DNA replication, the p53 signaling pathway, and the cell cycle. After constructing a protein-protein interaction (PPI) network and screening out a prominent cluster, 14 involved in the cell cycle process was identified. Consistently, ZBH-01 induced G0/G1 phase arrest in colon cancer cells, while CPT-11/SN38 caused S phase arrest. The initiation of apoptosis by ZBH-01 was also superior to CPT-11/SN38, followed by the increased expression of Bax, active caspase 3, and cleaved-PARP, and decreased expression of Bcl-2. Additionally, CCNA2 (cyclin A2), CDK2 (cyclin-dependent kinase 2), and MYBL2 (MYB proto-oncogene like 2) might be involved in the G0/G1 cell cycle arrest induced by ZBH-01. CONCLUSIONS: ZBH-01 can be an antitumor candidate drug for preclinical study in the future.

Arctigenin derivatives improve exercise performance in mice: synthesis and biological evaluation.

Arctigenin (ARG) has potent antifatigue activity, but its clinical application has been restricted for its poor water solubility. In this study, seven ARG derivatives containing different amino acids coupled via an ethoxy linker were synthesized, and tested for their solubility, as well as activities to improve exercise performance in mice. All of the derivatives showed improved solubility compared to that of ARG. Derivative Z-A-6 exhibited the highest activity, showing that the mice ran a 4.88-fold greater distance in the running wheel test and swam a 2.86-fold greater time in the swimming test than those in the blank control group. Z-A-6 treatment increased the plasma superoxide dismutase and catalase concentrations as well as reduced lactic acid and blood urea nitrogen accumulation during exercise. Z-A-6 treatment enhanced the phosphorylation of adenosine monophosphate-activated protein kinase, and no acute toxicity was observed. The results will contribute to the development of potential antifatigue agents.

Studies on the Effect of Lipofectamine and Cell-Penetrating Peptide on the Properties of 10-23 DNAzyme.

Cationic polymeric materials and cell-penetrating peptides (CPPs) were often used as the delivery vectors in the evaluation of nucleic acid therapeutics. 10-23 DNAzyme is a kind of potential antisense therapeutics by catalytic cleavage of the disease-related RNAs. Here, lipofectamine 2000 and Tat peptide were evaluated for their effect on the catalytic activity of 10-23 DNAzyme, with the observed rate constant, thermal stability, CD spectra, and PAGE analysis, with a duplex DNA mimicking DNAzyme-substrate as a control. It was shown that the cationic carriers had a negative effect on the catalytic performance of the 10-23 DNAzyme. Significantly, the destabilizing effect of the cationic carriers on the duplex formation was noteworthy, as a duplex formation is an essential prerequisite in the silencing mechanisms of antisense and RNAi.

A contact-polymerizable hemostatic powder for rapid hemostasis.

The immediate control of a hemorrhage is crucial for reducing fatalities in critical situations such as battlefields, traffic accidents, natural disasters, etc. Most existing commercial hemostatic powders have weak adhesion capability and poor biodegradability, restricting their clinical use. In this paper, a new poly(ethylene glycol)-di(cyanoacrylate) (CA-PEG-CA)-based hemostatic powder with tissue-contact-triggered strong adhesion and controlled fast degradation is proposed. The monomers quickly underwent crosslinking polymerization while in contact with tissue or blood, forming an in situ gel on the wound. The hemostatic mechanism was demonstrated to depend on both adhesive-based sealing and the aggregation of platelets and erythrocytes. The powder showed excellent hemostatic effects both in vitro and in vivo, even in a rat model with a weakened native hemostatic capacity. In addition, the poly-CA-PEG-CA gel could be rapidly biodegraded by ester bond hydrolysis. Notably, a cysteamine (CS)-containing solution could accelerate the degradation rate, endowing the gel with an on-demand removal property. This hemostatic powder not only can be used to efficiently control bleeding in emergency scenarios, but it can also allow nontraumatic re-exposure of wounds during subsequent surgical care. These properties make the CA-PEG-CA powder a promising candidate to act as a multifunctional wound care agent for first aid.

Discovery and Structural Explorations of G-Protein Biased µ-Opioid Receptor Agonists.

Compounds that activate only the G-protein signalling pathway represent an effective strategy for making safer opioids. In the present study, we report the design, synthesis and evaluation of two classes of novel PZM21 derivatives containing the benzothiophene ring and biphenyl ring group respectively as biased µ-opioid receptor (µOR) agonists. The new compound SWG-LX-33 showed potent µOR agonist activity and produced µOR-dependent analgesia. SWG-LX-33 does not activate the ß-arrestin-2 signalling pathway in vitro even at high concentrations. Computational docking demonstrated the amino acid residue ASN150 to be critical for the weak efficacy and potency of µOR agonists in arrestin recruitment.

A novel irinotecan derivative ZBH-1207 with different anti-tumor mechanism from CPT-11 against colon cancer cells.

PURPOSE: Irinotecan (CPT-11) is a camptothecin derivative whose potent anti-tumor activity depends on the rapid formation of an in vivo active metabolite, SN38 (7-ethyl-10-hydroxycamptothecin). CPT-11 combine with other agents are often the treatment of choice for patients with advanced or metastatic colorectal cancer (CRC). This study evaluates the cytotoxic mechanism of a novel CPT-11 derivative, ZBH-1207 in CRC cells in vitro. METHODS: The anti-proliferation effect of ZBH-1207 on tumor cells was assessed by MTT assay. The inhibition of TOP1, the alteration of cell cycle and apoptosis, and the expression of caspase-3 and PARP in CRC cells induced by ZBH-1207 were detected by DNA relaxation assay, flow cytometry, and Western blot, respectively. RESULTS: ZBH-1207 significantly inhibits the proliferation of seven tumor cell lines and retains the activity of TOP1 as compared with CPT-11. Treatment with ZBH-1207 results in more apparent cell cycle arrests and apoptosis of CRC cells than that of CPT-11 and SN38. Accordingly, up-regulation of active caspase-3 and PARP expression were relatively higher in ZBH-1207 group than that in CPT-11 and SN38 group. CONCLUSION: ZBH-1207 has higher cytotoxicity than CPT-11/SN38 in CRC cells. Its molecular mechanism involves apoptosis signaling pathway.

[Time-dependent injury of mouse cerebral cortex and hippocampus by acute hypoxia].

The aim of this study was to investigate the harmful effects of acute hypoxia on mouse cerebral cortex and hippocampus and the underlying mechanism. Mouse model of acute hypoxia was constructed by using a sealed glass jar. Laser speckle contrast imaging was used to detect the changes of cerebral blood flow after different time duration of hypoxia. Total superoxide dismutase (T-SOD) and malondialdehyde (MDA) assay kits were used to detect oxidative stress in cerebral cortex and hippocampus. Immunofluorescent staining was used to detect neuroinflammatory response of microglia in the cerebral cortex and hippocampus. One-step TUNEL method was used to detect neuronal apoptosis. The results showed that, compared with non-hypoxia (0 min hypoxia) group, 30 min hypoxia group exhibited decreased cerebral blood flow, higher percentage of CD68+/Iba1+ microglia, and increased neural apoptosis in the cerebral cortex and hippocampus. Compared with 30 min group, 60 min hypoxia group showed significantly decreased cerebral blood flow, increased MDA content in the cortex, as well as greater percentage of CD68+/Iba1+ microglia and neuronal apoptosis in the cerebral cortex and hippocampus. These results suggest that acute hypoxia damages brain tissue in a time-dependent manner and the oxidative stress and neuroinflammation are important mechanisms.

Icaridin-Loading Nitrocellulose As a New Repellent Against Aquatic Leech with Waterproof and Long-Acting Properties.

Leech attachment is a common nuisance to outdoor recreationists and farmers in aquatic environments. Consequences include bleeding, infection, and, rarely, death. Methods to prevent leech attachment are anecdotal and individual; effective repellent formulations with universal applicability are needed. In this study, icaridin is demonstrated to be repellent and toxic to aquatic leech, and formulation of icaridin loading nitrocellulose (Icar-Nitr) is proposed as a new leech repellent. The nitrocellulose provided sustained drug release and waterproof properties. One optimal formulation, 10-Icar-Nitr, proved effective for leech repelling in aquatic environment. Using a rat model, the same formulation also showed removal and killing after leech attachment. The nitrocellulose reduced percutaneous absorption of icaridin, and 10-Icar-Nitr showed good biocompatibility. This study provides a potential new and practicable strategy for prevention and removal against leech attachment and bites.

Synthesis and Evaluation of Novel α-Aminoamides Containing Benzoheterocyclic Moiety for the Treatment of Pain.

Novel α-aminoamide derivatives containing different benzoheterocyclics moiety were synthesized and evaluated as voltage-gated sodium ion channels blocks the treatment of pain. Compounds 6a, 6e, and 6f containing the benzofuran group displayed more potent in vivo analgesic activity than ralfinamide in both the formalin test and the writhing assay. Interestingly, they also exhibited potent in vitro anti-Nav1.7 and anti-Nav1.8 activity in the patch-clamp electrophysiology assay. Therefore, compounds 6a, 6e, and 6f, which have inhibitory potency for two pain-related Nav targets, could serve as new leads for the development of analgesic medicines.

SCN11A gene deletion causes sensorineural hearing loss by impairing the ribbon synapses and auditory nerves.

BACKGROUND: The SCN11A gene, encoded Nav1.9 TTX resistant sodium channels, is a main effector in peripheral inflammation related pain in nociceptive neurons. The role of SCN11A gene in the auditory system has not been well characterized. We therefore examined the expression of SCN11A in the murine cochlea, the morphological and physiological features of Nav1.9 knockout (KO) ICR mice. RESULTS: Nav1.9 expression was found in the primary afferent endings beneath the inner hair cells (IHCs). The relative quantitative expression of Nav1.9 mRNA in modiolus of wild-type (WT) mice remains unchanged from P0 to P60. The number of presynaptic CtBP2 puncta in Nav1.9 KO mice was significantly lower than WT. In addition, the number of SGNs in Nav1.9 KO mice was also less than WT in the basal turn, but not in the apical and middle turns. There was no lesion in the somas and stereocilia of hair cells in Nav1.9 KO mice. Furthermore, Nav1.9 KO mice showed higher and progressive elevated ABR threshold at 16 kHz, and a significant increase in CAP thresholds. CONCLUSIONS: These data suggest a role of Nav1.9 in regulating the function of ribbon synapses and the auditory nerves. The impairment induced by Nav1.9 gene deletion mimics the characters of cochlear synaptopathy.

Design of a Novel Nucleus-Targeted NLS-KALA-SA Nanocarrier to Delivery Poorly Water-Soluble Anti-Tumor Drug for Lung Cancer Treatment.

In this study, we designed a novel nucleus-targeted nanocarrier (NLS-KALA-SA, NKSN) consisting of Kala peptide (KALA), nuclear localization signal (NLS) and stearic acid (SA) using Fmoc solid phase synthesis method. We chose Curcumin (CUR), Paclitaxel (PTX), Ginsenoside compound K(CK) as models of poorly water-soluble antitumor drugs, The drugs loaded NLS-KALA-SA nanoparticles (CUR/NKSN, PTX/NKSN, CK/NKSN) were obained by the dialysis method, their physicochemical properties were determined and antitumor activity were evaluated. The NLS-KALA-SA nanoparticles were spherical shaped with an average size of 76.4 ± 7.6 mm and a zeta potential of 43.7 ± 5.8 mV. The drug-loaded NLS-KALA-SA nanoparticles were above 86.1% and 17.1% in entrapment efficiency and drug loading capacity, and had sustained drug release behavior. Biodistribution and cellular uptake study exhibited that PTX/NKSN mainly distributed in tumor site of A549-bearing mice, and coumarin-6(C6) loaded NLS-KALA-SA nanoparticle (C6/NKSN) was predominantly accumulated in the nucleus of A549 cells. Western blot analysis indicated that PTX/NKSN could more remarkably inhibit Bcl-2 expression and enhance the expression of Bax and Caspase-3 as compared to the controls in A549 cells. Cell apoptosis and antitumor activity study showed that PXT/NKSN could more obviously induce apoptosis of A549 cells compared with free PXT, the PTX/NKSN administration was more effective than free PTX for lung cancer treatment and displayed mild toxicity in A549-bearing mice. The results demonstrates that the NLS-KALA-SA nanoparticles system could enhance the antitumor effects of the encapsulated drug and reduce tissue toxicity due to its long circulating properties and tumor targeting, which might provide a promising strategy for lung cancer treatment.

Engagement Enhancement Based on Human-in-the-Loop Optimization for Neural Rehabilitation.

Enhancing patients' engagement is of great benefit for neural rehabilitation. However, physiological and neurological differences among individuals can cause divergent responses to the same task, and the responses can further change considerably during training; both of these factors make engagement enhancement a challenge. This challenge can be overcome by training task optimization based on subjects' responses. To this end, an engagement enhancement method based on human-in-the-loop optimization is proposed in this paper. Firstly, an interactive speed-tracking riding game is designed as the training task in which four reference speed curves (RSCs) are designed to construct the reference trajectory in each generation. Each RSC is modeled using a piecewise function, which is determined by the starting velocity, transient time, and end velocity. Based on the parameterized model, the difficulty of the training task, which is a key factor affecting the engagement, can be optimized. Then, the objective function is designed with consideration to the tracking accuracy and the surface electromyogram (sEMG)-based muscle activation, and the physical and physiological responses of the subjects can consequently be evaluated simultaneously. Moreover, a covariance matrix adaption evolution strategy, which is relatively tolerant of both measurement noises and human adaptation, is used to generate the optimal parameters of the RSCs periodically. By optimization of the RSCs persistently, the objective function can be maximized, and the subjects' engagement can be enhanced. Finally, the performance of the proposed method is demonstrated by the validation and comparison experiments. The results show that both subjects' sEMG-based motor engagement and electroencephalography based neural engagement can be improved significantly and maintained at a high level.

Enhanced Motor Imagery Based Brain- Computer Interface via FES and VR for Lower Limbs.

Motor imagery based brain-computer interface (MI-BCI) has been studied for improvement of patients' motor function in neurorehabilitation and motor assistance. However, the difficulties in performing imagery tasks limit its application. To overcome the limitation, an enhanced MI-BCI based on functional electrical stimulation (FES) and virtual reality (VR) is proposed in this study. On one hand, the FES is used to stimulate the subjects' lower limbs before their imagination to make them experience the muscles' contraction and improve their attention on the lower limbs, by which it is supposed that the subjects' motor imagery (MI) abilities can be enhanced. On the other hand, a ball-kicking movement scenario from the first-person perspective is designed to provide visual guidance for performing MI tasks. The combination of FES and VR can be used to reduce the difficulties in performing MI tasks and improve classification accuracy. Finally, the comparison experiments were conducted on twelve healthy subjects to validate the performance of the enhanced MI-BCI. The results show that the classification performance can be improved significantly by using the proposed MI-BCI in terms of the classification accuracy (ACC), the area under the curve (AUC) and the F1 score (paired t-test, ).

Site-specific functionalization with amino, guanidinium, and imidazolyl groups enabling the activation of 10-23 DNAzyme.

10-23 DNAzyme has been extensively explored as a therapeutic and biotechnological tool, as well as in DNA computing. Faster cleavage or transformation is always needed. The present research displays a rational modification approach for a more efficient DNAzyme. In the catalytic core, amino, guanidinium and imidazolyl groups were introduced for its chemical activation through the adenine base. Among the six adenine residues, A9 is the unique residue that realizes all the positive effects; the 6-amino and 8-position of adenine and the 7-position of 8-aza-7-deaza-adenine could be used for the introduction of the functional groups. A12 is a new choice for catalytic improvement with an 8-substituent. Therefore, more active DNAzymes could be expected by this nucleobase-modified activation approach.

Yttrium vanadates based ratiometric fluorescence probe for alkaline phosphatase activity sensing.

Alkaline phosphatase (ALP) is an important biomarker for diagnosis, and the abnormal level of serum ALP is closely related to a variety of diseases. In present work, a ratiometric fluorescence probe based on hybrid nanoparticles CDs@YVO4: Dy3+ nanoparticle is introduced for alkaline phosphatase (ALP) activity determination. The CDs@YVO4: Dy3+ probe is constructed by the carbon dots (CDs) and YVO4: Dy3+ through a simple mixing method, in which the blue emission of CDs at 405 nm acts as the calibrated signal, the green emission of YVO4: Dy3+ at 574 nm decreased with the increasing targets ALP, and used as the output signal. In addition, the Cu2+ and pyrophosphate (PPi) were also employed in this strategy to utilize the excellent fluorescnece quenching efficiency of Cu2+ to the Dy3+ ions emission of CDs@YVO4: Dy3+, as well as the strong affinity of PPi for Cu2+. In the presence of analyts ALP, ALP catalyzes the hydrolysis of PPi, causing the release of Cu2+, resulting in the Dy3+ ions emission quenched, while the CDs emission at 405 nm retained unchanged, based on this, we designed the off-on-off ratiometric fluorescence platform for ALP sensing. The experiment result shows that the ratio of F574/F405 is linear to the concentration of ALP in arange of 0.05∼3000 U/L with a detection limit of 0.04 U/L, which is comparable or better than those reported fluorescence probe, especially the calibrated signal introduction of CDs can eliminate the background interference, improve the accuracy of proposed probe greatly. Furthermore, the discrimination of ALP enzyme inhibitor with the IC50 of 26 µM, and ALP concentration in real human serum sample has also demonstrated the applicability of CDs@YVO4: Dy3+ fluorescence sensor well.

Discovery of Biased Mu-Opioid Receptor Agonists for the Treatment of Pain.

G protein-biased mu-opioid receptor (MOR) agonists have been developed as promising new potent analgesic drugs with fewer adverse side effects than standard MOR agonists. PZM21 represents a unique chemotype unrelated to known opioids, which makes it a desirable lead for modification to find analgesics with new chemical entities. In the present study, we synthesized and tested novel PZM21 derivatives as potent biased MOR agonists by introducing a benzodioxolane group to replace the hydroxybenzene of PZM21. The new compounds displayed more potent analgesic activities in vivo and greater bias toward G protein signaling in vitro than did PZM21. These results suggest that the benzodioxolane group is essential for the maintenance of bias. Compounds 7 i ((S)-1-(3-(benzo[d][1,3]dioxol-4-yl)-2-(dimethylamino)propyl)-3-phenethylurea) and 7 j ((S)-1-(3-(benzo[d][1,3]dioxol-4-yl)-2-(dimethylamino)propyl)-3-benzylurea) could serve as new leads for further modifications to find novel biased MOR agonists with greater G protein signaling potency and less ß-arrestin-2 recruitment.