GPCR-Mediated Natural Products and Compounds: Potential Therapeutic Targets for the Treatment of Neurological Diseases.

G protein-coupled receptors (GPCRs), widely expressed in the human central nervous system (CNS), perform numerous physiological functions and play a significant role in the pathogenesis of diseases. Consequently, identifying key therapeutic GPCRs targets for CNS-related diseases is garnering immense interest in research labs and pharmaceutical companies. However, using GPCRs drugs for treating neurodegenerative diseases has limitations, including side effects and uncertain effective time frame. Recognizing the rich history of herbal treatments for neurological disorders like stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), modern pharmacological research is now focusing on the understanding of the efficacy of traditional Chinese medicinal herbs and compounds in modulating GPCRs and treatment of neurodegenerative conditions. This paper will offer a comprehensive, critical review of how certain natural products and compounds target GPCRs to treat neurological diseases. Conducting an in-depth study of herbal remedies and their efficacies against CNS-related disorders through GPCRs targeting will augment our strategies for treating neurological disorders. This will not only broaden our understanding of effective therapeutic methodologies but also identify the root causes of altered GPCRs signaling in the context of pathophysiological mechanisms in neurological diseases. Moreover, it would be informative for the creation of safer and more effective GPCR-mediated drugs, thereby establishing a foundation for future treatment of various neurological diseases.

Caulerpa chemnitzia polysaccharide exerts immunomodulatory activity in macrophages by mediating the succinate/PHD2/HIF-1α/IL-1ß pathway.

Algal polysaccharide is an important food functional factor with diverse bioactive and low toxicity. Previous studies have confirmed Caulerpa chemnitzia polysaccharides (CRVP) have immunomodulatory activity, but the immunomodulatory mechanism of CRVP in macrophages has not been thoroughly explored yet. In our research, we found that CRVP has outstanding immunomodulatory activity in macrophages, which is reflected in promoting cell proliferation, upregulating cytokines (IL-1ß, IL-6, and TNF-α) expression, and increasing NO and ROS levels. Additionally, the result of joint analysis of untargeted metabolomics showed metabolism played a major role in the immunomodulatory of CRVP and suggested succinic acid was a key metabolite. Further verification indicated that the accumulation of succinic acid in macrophages after administered with CRVP, induced the down-regulation of prolyl hydroxylase domain 2 (PHD2) and up-regulation of hypoxia-inducible factor-1α (HIF-1α), thereby enhancing IL-1ß expression. Together, the immunomodulatory activity of CRVP in macrophages via succinate/PHD2/HIF-1α/IL-1ß pathway.

Far-infrared radiation and its therapeutic parameters: A superior alternative for future regenerative medicine?

In future regenerative medicine, far-infrared radiation (FIR) may be an essential component of optical therapy. Many studies have confirmed or validated the efficacy and safety of FIR in various diseases, benefiting from new insights into FIR mechanisms and the excellent performance of many applications. However, the lack of consensus on the biological effects and therapeutic parameters of FIR limits its practical applications in the clinic. In this review, the definition, characteristics, and underlying principles of the FIR are systematically illustrated. We outline the therapeutic parameters of FIR, including the wavelength range, power density, irradiation time, and distance. In addition, the biological effects, potential molecular mechanisms, and preclinical and clinical applications of FIR are discussed. Furthermore, the future development and applications of FIR are described in this review. By applying optimal therapeutic parameters, FIR can influence various cells, animal models, and patients, eliciting diverse underlying mechanisms and offering therapeutic potential for many diseases. FIR could represent a superior alternative with broad prospects for application in future regenerative medicine.

Sirt7 protects against vascular calcification via modulation of reactive oxygen species and senescence of vascular smooth muscle cells.

Vascular calcification is frequently seen in patients with chronic kidney disease (CKD), and significantly increases cardiovascular mortality and morbidity. Sirt7, a NAD+-dependent histone deacetylases, plays a crucial role in cardiovascular disease. However, the role of Sirt7 in vascular calcification remains largely unknown. Using in vitro and in vivo models of vascular calcification, this study showed that Sirt7 expression was significantly reduced in calcified arteries from mice administered with high dose of vitamin D3 (vD3). We found that knockdown or inhibition of Sirt7 promoted vascular smooth muscle cell (VSMC), aortic ring and vascular calcification in mice, whereas overexpression of Sirt7 had opposite effects. Intriguingly, this protective effect of Sirt7 on vascular calcification is dependent on its deacetylase activity. Unexpectedly, Sirt7 did not alter the osteogenic transition of VSMCs. However, our RNA-seq and subsequent studies demonstrated that knockdown of Sirt7 in VSMCs resulted in increased intracellular reactive oxygen species (ROS) accumulation, and induced an Nrf-2 mediated oxidative stress response. Treatment with the ROS inhibitor N-acetylcysteine (NAC) significantly attenuated the inhibitory effect of Sirt7 on VSMC calcification. Furthermore, we found that knockdown of Sirt7 delayed cell cycle progression and accelerated cellular senescence of VSMCs. Taken together, our results indicate that Sirt7 regulates vascular calcification at least in part through modulation of ROS and cellular senescence of VSMCs. Sirt7 may be a potential therapeutic target for vascular calcification.

Colon cancer inhibitory properties of Caulerpa lentillifera polysaccharide and its molecular mechanisms based on three-dimensional cell culture model.

Caulerpa lentillifera is rich in polysaccharides, and its polysaccharides show a significant effect in different biological activities including anti-cancer activity. As an edible algae-derived polysaccharide, exploring the role of colon cancer can better develop the application from a dietary therapy perspective. However, more in-depth studies of C. lentillifera polysaccharide on anti-colon cancer activity and mechanism are needed. In this study, we found that Caulerpa lentillifera polysaccharides (CLP) showed potential anti-colon cancer effect on human colon cancer cell HT29 in monolayer (IC50 = 1.954 mg/mL) and spheroid (IC50 = 0.402 mg/mL). Transcriptomics and metabolomics analyses revealed that CLP had an inhibitory effect on HT29 3D spheroid cells by activating aminoacyl-tRNA biosynthesis as well as arginine and proline metabolism pathways. Furthermore, the anti-colon cancer effects of CLP were confirmed through other human colon cancer cell HCT116 and LoVo in monolayer cells (IC50 = 1.890 mg/mL and 1.437 mg/mL, respectively) and 3D spheroid cells (IC50 = 0.344 mg/mL and 0.975 mg/mL, respectively), and three patient-derived organoids with IC50 values of 6.333-8.780 mg/mL. This study provided basic data for the potential application of CLP in adjuvant therapeutic food for colon cancer on multiple levels, while further investigation of detailed mechanism in vivo was still required.

Structural characterization and ferroptosis-related immunomodulatory of a novel exopolysaccharide isolated from marine fungus Aspergillus medius.

Marine fungal exopolysaccharides play a crucial role in immunoregulation. In this investigation, a novel polysaccharide was extracted from the culture medium of the marine fungus Aspergillus medius SCAU-236. Compositional analysis revealed a structure composed of glucose units with (1,4)-α-D-Glcp, (1,3,4)-ß-D-Glcp, and (1,4,6)-α-D-Glcp, along with side chains of 1-α-D-Glcp linked to carbon 6 of (1,4,6)-α-D-Glcp and carbon 3 of (1,3,4)-ß-D-Glcp. Functional evaluations on RAW264.7 macrophage cells demonstrated Aspergillus medius polysaccharide (ASMP)'s effects on cell proliferation, nitric oxide levels, and the secretion of TNF-α, IL-6, and IL-1ß cytokines. Additionally, metabolomics indicated ASMP's potential to modulate macrophage immune function by impacting key regulatory molecules, including COX-2, iNOS, Nrf2, SLC7A11, GPX4, and ACSL4. The Nrf2/SLC7A11/GPX4 axis and ACSL4 were suggested to be involved in ASMP-induced ferroptosis, leading to increased reactive oxygen species (ROS) levels and lipid peroxidation. These findings propose a unique mechanism by which ASMP exerts immunomodulatory effects through ferroptosis induction, contributing to the understanding of marine-derived compounds in immunomodulation research.

Potential enhancement of post-stroke angiogenic response by targeting the oligomeric aggregation of p53 protein.

Tumor suppressor gene p53 and its aggregate have been found to be involved in many angiogenesis-related pathways. We explored the possible p53 aggregation formation mechanisms commonly occur after ischemic stroke, such as hypoxia and the presence of reactive oxygen species (ROS). The angiogenic pathways involving p53 mainly occur in nucleus or cytoplasm, with one exception that occurs in mitochondria. Considering the high mitochondrial density in brain and endothelial cells, we proposed that the cyclophilin D (CypD)-dependent vascular endothelial cell (VECs) necrosis pathway occurring in the mitochondria is one of the major factors that affects angiogenesis. Hence, targeting p53 aggregation, a key intermediate in the pathway, could be an alternative therapeutic target for post-stroke management.

Sulfated heteropolysaccharides from Undaria pinnatifida: Structural characterization and transcript-metabolite profiling of immunostimulatory effects on RAW264.7 cells.

Investigation of the polysaccharides from an edible marine brown algae Undaria pinnatifida has led to obtaining three fractional sulfated polysaccharides UPPs 1-3 with molecular weights of 7.212 kDa, 13.924 kDa, and 55.875 kDa, respectively. All UPPs are composed of galactose, xylose, glucose, mannose, glucuronic acid, and mannuronic acid, while UPP-3 also consisted of fucose, arabinose, and fructose. The immunostimulatory assay revealed that UPP-3 had important effects on cell viability, nitric oxide levels, and secretion of cytokines TNF-α and IL-6 in RAW264.7 cells. Furthermore, the transcript-metabolite data along with western blot and immunofluorescent staining revealed that UPP-3 could stimulate the Toll-like receptor (TLR4) associated with the nuclear factor kappa-B (NF-κB) p65 signaling pathway of RAW264.7 cells. These findings of the immunomodulatory sulfated polysaccharide will provide a basic understanding to further exploitation of U. pinnatifida polysaccharides.

Corrigendum to "Sulfated heteropolysaccharides from Undaria pinnatifida: Structural characterization and transcript-metabolite profiling of immunostimulatory effects on RAW264.7 cells" [Food Chemistry: X 13 (2022) 100251].

[This corrects the article DOI: 10.1016/j.fochx.2022.100251.].

Teaching bioelectricity and neurophysiology to medical students using LabAXON simulations.

Patch-clamp electrophysiological recordings of neuronal activity require a large amount of space and equipment. The technique is difficult to master and not conducive to demonstration to more than a few medical students. Therefore, neurophysiological education is mostly limited to classroom-based pedagogies such as lectures. However, the demonstration of concepts such as changes in membrane potential and ion channel activity is best achieved with hands-on approaches. This article details an in silico activity suitable for large groups of medical students that demonstrates the key concepts in neurophysiology using the LabAXON simulation software. Learning activities in our practical include 1) measurements of voltage and time parameters of the neuronal action potential and its relationship to the Nernst potentials of Na+ and K+; 2) determination of the stimulus threshold to evoke action potentials; 3) demonstration of the refractory period of an action potential; and 4) voltage-clamp experiments to determine the current-voltage relationship of voltage-gated Na+ and K+ channels and the voltage dependence of, and recovery from, inactivation of voltage-gated Na+ channels. We emphasized the accuracy of quantitative measurements as well as the correct use of units. The level of difficulty of the activity can be altered through different multiple choice questions relating to material introduced in the associated lectures. This practical activity is suitable for different class sizes and is adaptable for delivery with online platforms. Student feedback showed that the students felt the activity helped them consolidate their understanding of the lecture material.

Immunomodulatory sulfated polysaccharides from Caulerpa racemosa var. peltata induces metabolic shifts in NF-κB signaling pathway in RAW 264.7 macrophages.

Algal polysaccharide activates macrophages to alter physiologic biomarkers to drive the immunomodulatory phenotype, but it lacks specific biomarkers involved in the biochemical underpinning process. Here, we undertook an extensive analysis of the RAW 264.7 macrophages induced by an immunostimulating sulfated polysaccharide from Caulerpa racemosa var. peltata (CRVP-1) employing combined transcriptomic, proteomic, and metabolomic analyses to reveal the molecular details occurring in the CRVP-1-induced immunomodulatory process. The omics profiling of CRVP-1-activated macrophage demonstrated a total of 8844 genes (4354 downregulated and 4490 upregulated), 1243 proteins (620 downregulated and 623 upregulated), and 68 metabolites (52 downregulated and16 upregulated). Further, the co-mapped correlation network of omics combined with Western blot and immunofluorescence staining indicated that the cluster of differentiation 14 (CD14) might assist Toll-like receptor 4 (TLR4) involved in nuclear factor kappa-B (NF-κB) signaling pathway to drive the immunomodulatory phenotype. Together, our results discover novel physiologic biomarkers in the immunomodulatory activities of algal polysaccharides.

The Fml1-MHF complex suppresses inter-fork strand annealing in fission yeast.

Previously we reported that a process called inter-fork strand annealing (IFSA) causes genomic deletions during the termination of DNA replication when an active replication fork converges on a collapsed fork (Morrow et al., 2017). We also identified the FANCM-related DNA helicase Fml1 as a potential suppressor of IFSA. Here, we confirm that Fml1 does indeed suppress IFSA, and show that this function depends on its catalytic activity and ability to interact with Mhf1-Mhf2 via its C-terminal domain. Finally, a plausible mechanism of IFSA suppression is demonstrated by the finding that Fml1 can catalyse regressed fork restoration in vitro.

Inter-Fork Strand Annealing causes genomic deletions during the termination of DNA replication.

Problems that arise during DNA replication can drive genomic alterations that are instrumental in the development of cancers and many human genetic disorders. Replication fork barriers are a commonly encountered problem, which can cause fork collapse and act as hotspots for replication termination. Collapsed forks can be rescued by homologous recombination, which restarts replication. However, replication restart is relatively slow and, therefore, replication termination may frequently occur by an active fork converging on a collapsed fork. We find that this type of non-canonical fork convergence in fission yeast is prone to trigger deletions between repetitive DNA sequences via a mechanism we call Inter-Fork Strand Annealing (IFSA) that depends on the recombination proteins Rad52, Exo1 and Mus81, and is countered by the FANCM-related DNA helicase Fml1. Based on our findings, we propose that IFSA is a potential threat to genomic stability in eukaryotes.

Bacteriophage T5 gene D10 encodes a branch-migration protein.

Helicases catalyze the unwinding of double-stranded nucleic acids where structure and phosphate backbone contacts, rather than nucleobase sequence, usually determines substrate specificity. We have expressed and purified a putative helicase encoded by the D10 gene of bacteriophage T5. Here we report that this hitherto uncharacterized protein possesses branch migration and DNA unwinding activity. The initiation of substrate unwinding showed some sequence dependency, while DNA binding and DNA-dependent ATPase activity did not. DNA footprinting and purine-base interference assays demonstrated that D10 engages these substrates with a defined polarity that may be established by protein-nucleobase contacts. Bioinformatic analysis of the nucleotide databases revealed genes predicted to encode proteins related to D10 in archaebacteria, bacteriophages and in viruses known to infect a range of eukaryotic organisms.

Characterization of an unusual bipolar helicase encoded by bacteriophage T5.

Bacteriophage T5 has a 120 kb double-stranded linear DNA genome encoding most of the genes required for its own replication. This lytic bacteriophage has a burst size of ∼500 new phage particles per infected cell, demonstrating that it is able to turn each infected bacterium into a highly efficient DNA manufacturing machine. To begin to understand DNA replication in this prodigious bacteriophage, we have characterized a putative helicase encoded by gene D2. We show that bacteriophage T5 D2 protein is the first viral helicase to be described with bipolar DNA unwinding activities that require the same core catalytic residues for unwinding in either direction. However, unwinding of partially single- and double-stranded DNA test substrates in the 3'-5' direction is more robust and can be distinguished from the 5'-3' activity by a number of features including helicase complex stability, salt sensitivity and the length of single-stranded DNA overhang required for initiation of helicase action. The presence of D2 in an early gene cluster, the identification of a putative helix-turn-helix DNA-binding motif outside the helicase core and homology with known eukaryotic and prokaryotic replication initiators suggest an involvement for this unusual helicase in DNA replication initiation.