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The Journal of Clinical Investigation Sep 2023Asthma is a chronic inflammatory disease associated with episodic airway narrowing. Inhaled β2-adrenergic receptor (β2AR) agonists (β2-agonists) promote - with...
Asthma is a chronic inflammatory disease associated with episodic airway narrowing. Inhaled β2-adrenergic receptor (β2AR) agonists (β2-agonists) promote - with limited efficacy - bronchodilation in asthma. All β2-agonists are canonical orthosteric ligands that bind the same site as endogenous epinephrine. We recently isolated a β2AR-selective positive allosteric modulator (PAM), compound-6 (Cmpd-6), which binds outside of the orthosteric site and modulates orthosteric ligand functions. With the emerging therapeutic potential of G-protein coupled receptor allosteric ligands, we investigated the impact of Cmpd-6 on β2AR-mediated bronchoprotection. Consistent with our findings using human β2ARs, Cmpd-6 allosterically potentiated β2-agonist binding to guinea pig β2ARs and downstream signaling of β2ARs. In contrast, Cmpd-6 had no such effect on murine β2ARs, which lack a crucial amino acid in the Cmpd-6 allosteric binding site. Importantly, Cmpd-6 enhanced β2 agonist-mediated bronchoprotection against methacholine-induced bronchoconstriction in guinea pig lung slices, but - in line with the binding studies - not in mice. Moreover, Cmpd-6 robustly potentiated β2 agonist-mediated bronchoprotection against allergen-induced airway constriction in lung slices obtained from a guinea pig model of allergic asthma. Cmpd-6 similarly enhanced β2 agonist-mediated bronchoprotection against methacholine-induced bronchoconstriction in human lung slices. Our results highlight the potential of β2AR-selective PAMs in the treatment of airway narrowing in asthma and other obstructive respiratory diseases.
Topics: Humans; Mice; Animals; Guinea Pigs; Methacholine Chloride; Ligands; Asthma; Lung; Binding Sites; Receptors, Adrenergic, beta-2
PubMed: 37432742
DOI: 10.1172/JCI167337 -
Current Nutrition Reports May 2024This review draws on the last fifteen years (2009-2024) of published data to summarize the potential effect of plant flavonoids on pancreatic carcinogenesis and discuss... (Review)
Review
PURPOSE OF REVIEW
This review draws on the last fifteen years (2009-2024) of published data to summarize the potential effect of plant flavonoids on pancreatic carcinogenesis and discuss the possible mechanisms of action to establish their applicability as anti-cancer agents.
RECENT FINDINGS
This review found that the plant flavonoids with anti-pancreatic cancer activity mainly include chalcones, dihydrochalcones, flavanols, flavanones, flavones, isoflavonoids, flavonols, isoflavones, and flavanonols. Most of these flavonoids have anti-proliferative, pro-apoptotic, cell cycle arrest, anti-angiogenic, anti-inflammatory, anti-epithelial-mesenchymal transition, and anti-metastatic properties. Some flavonoids can also regulate autophagy, immune and glucose uptake in the context of pancreatic cancer. Several molecules and signaling pathways are associated with the pharmacological activities of plant flavonoids, including AMP-activated protein kinase, mitogen-activated protein kinases, phosphatidylinositol-3-kinase/protein kinase B, nuclear factor-κB, signal transducer, and activator of transcription 3, Smad3, epidermal growth factor receptor, and vascular endothelial growth factor. This review provides strong evidence that plant flavonoids have potential against pancreatic carcinogenesis in experimental animals through various pharmacological mechanisms. They are a promising resource for use as adjuvant anti-cancer therapy. However, randomized controlled clinical trials with those flavonoids are needed.
PubMed: 38700837
DOI: 10.1007/s13668-024-00545-9 -
Cell May 2024The cystic fibrosis transmembrane conductance regulator (CFTR) is a crucial ion channel whose loss of function leads to cystic fibrosis, whereas its hyperactivation...
The cystic fibrosis transmembrane conductance regulator (CFTR) is a crucial ion channel whose loss of function leads to cystic fibrosis, whereas its hyperactivation leads to secretory diarrhea. Small molecules that improve CFTR folding (correctors) or function (potentiators) are clinically available. However, the only potentiator, ivacaftor, has suboptimal pharmacokinetics and inhibitors have yet to be clinically developed. Here, we combine molecular docking, electrophysiology, cryo-EM, and medicinal chemistry to identify CFTR modulators. We docked ∼155 million molecules into the potentiator site on CFTR, synthesized 53 test ligands, and used structure-based optimization to identify candidate modulators. This approach uncovered mid-nanomolar potentiators, as well as inhibitors, that bind to the same allosteric site. These molecules represent potential leads for the development of more effective drugs for cystic fibrosis and secretory diarrhea, demonstrating the feasibility of large-scale docking for ion channel drug discovery.
PubMed: 38810646
DOI: 10.1016/j.cell.2024.04.046 -
BioRxiv : the Preprint Server For... Aug 2023The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered as a...
The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered as a TMEM16A inhibitor for treating asthma and chronic obstructive pulmonary disease, but was recently found to possess broad-spectrum off-target effects. Here we show that, under physiological conditions, niclosamide acutely potentiates TMEM16A without having any inhibitory effect. Our computational and functional characterizations pinpoint a putative niclosamide binding site on the extracellular side of TMEM16A. Mutations in this site attenuate the potentiation. Moreover, niclosamide potentiates endogenous TMEM16A in vascular smooth muscle cells, triggers intracellular calcium increase, and constricts the murine mesenteric artery. Our findings advise caution when considering niclosamide as a TMEM16A inhibitor to treat diseases such as asthma, COPD, and hypertension. The identification of the putative niclosamide binding site provides insights into the mechanism of TMEM16A pharmacological modulation, shining light on developing specific TMEM16A modulators to treat human diseases.
PubMed: 37577682
DOI: 10.1101/2023.07.31.551400 -
The Journal of Neuroscience : the... Aug 2023Aberrant activation of presynaptic NMDARs in the spinal dorsal horn is integral to opioid-induced hyperalgesia and analgesic tolerance. However, the signaling mechanisms...
Aberrant activation of presynaptic NMDARs in the spinal dorsal horn is integral to opioid-induced hyperalgesia and analgesic tolerance. However, the signaling mechanisms responsible for opioid-induced NMDAR hyperactivity remain poorly identified. Here, we show that repeated treatment with morphine or fentanyl reduced monomeric mGluR5 protein levels in the dorsal root ganglion (DRG) but increased levels of mGluR5 monomers and homodimers in the spinal cord in mice and rats of both sexes. Coimmunoprecipitation analysis revealed that monomeric and dimeric mGluR5 in the spinal cord, but not monomeric mGluR5 in the DRG, directly interacted with GluN1. By contrast, mGluR5 did not interact with μ-opioid receptors in the DRG or spinal cord. Repeated morphine treatment markedly increased the mGluR5-GluN1 interaction and protein levels of mGluR5 and GluN1 in spinal synaptosomes. The mGluR5 antagonist MPEP reversed morphine treatment-augmented mGluR5-GluN1 interactions, GluN1 synaptic expression, and dorsal root-evoked monosynaptic EPSCs of dorsal horn neurons. Furthermore, CRISPR-Cas9-induced conditional mGluR5 knockdown in DRG neurons normalized mGluR5 levels in spinal synaptosomes and NMDAR-mediated EPSCs of dorsal horn neurons increased by morphine treatment. Correspondingly, intrathecal injection of MPEP or conditional mGluR5 knockdown in DRG neurons not only potentiated the acute analgesic effect of morphine but also attenuated morphine treatment-induced hyperalgesia and tolerance. Together, our findings suggest that opioid treatment promotes mGluR5 trafficking from primary sensory neurons to the spinal dorsal horn. Through dimerization and direct interaction with NMDARs, presynaptic mGluR5 potentiates and/or stabilizes NMDAR synaptic expression and activity at primary afferent central terminals, thereby maintaining opioid-induced hyperalgesia and tolerance. Opioids are essential analgesics for managing severe pain caused by cancer, surgery, and tissue injury. However, these drugs paradoxically induce pain hypersensitivity and tolerance, which can cause rapid dose escalation and even overdose mortality. This study demonstrates, for the first time, that opioids promote trafficking of mGluR5, a G protein-coupled glutamate receptor, from peripheral sensory neurons to the spinal cord; there, mGluR5 proteins dimerize and physically interact with NMDARs to augment their synaptic expression and activity. Through dynamic interactions, the two distinct glutamate receptors mutually amplify and sustain nociceptive input from peripheral sensory neurons to the spinal cord. Thus, inhibiting mGluR5 activity or disrupting mGluR5-NMDAR interactions could reduce opioid-induced hyperalgesia and tolerance and potentiate opioid analgesic efficacy.
Topics: Male; Female; Rats; Mice; Animals; Receptors, N-Methyl-D-Aspartate; Analgesics, Opioid; Hyperalgesia; Receptor, Metabotropic Glutamate 5; Rats, Sprague-Dawley; Morphine; Spinal Cord Dorsal Horn; Spinal Cord; Neuralgia; Sensory Receptor Cells
PubMed: 37451981
DOI: 10.1523/JNEUROSCI.0601-23.2023 -
CNS Neuroscience & Therapeutics Oct 2023We aimed to identify the neurotrophic activities of apigenin (4',5,7-trihydroxyflavone) via its coordination with brain-derived neurotrophic factor (BNDF) and an...
The neurotrophic activities of brain-derived neurotrophic factor are potentiated by binding with apigenin, a common flavone in vegetables, in stimulating the receptor signaling.
AIMS
We aimed to identify the neurotrophic activities of apigenin (4',5,7-trihydroxyflavone) via its coordination with brain-derived neurotrophic factor (BNDF) and an elevated signaling of tyrosine kinase receptor B (Trk B receptor).
METHODS
The direct binding of apigenin to BDNF was validated by ultrafiltration and biacore assay. Neurogenesis, triggered by apigenin and/or BDNF, was determined in cultured SH-SY5Y cells and rat cortical neurons. The amyloid-beta (Aβ) -induced cellular stress was revealed by propidium iodide staining, mitochondrial membrane potential, bioenergetic analysis, and formation of reactive oxygen species levels. Activation of Trk B signaling was tested by western blotting.
RESULTS
Apigenin and BDNF synergistically maintained the cell viability and promoted neurite outgrowth of cultured neurons. In addition, the BDNF-induced neurogenesis of cultured neurons was markedly potentiated by applied apigenin, including the induced expressions of neurofilaments, PSD-95 and synaptotagmin. Moreover, the synergy of apigenin and BDNF alleviated the (Aβ) -induced cytotoxicity and mitochondrial dysfunction. The synergy could be accounted by phosphorylation of Trk B receptor, and which was fully blocked by a Trk inhibitor K252a.
CONCLUSION
Apigenin potentiates the neurotrophic activities of BDNF through direct binding, which may serve as a possible treatment for its curative efficiency in neurodegenerative diseases and depression.
Topics: Rats; Humans; Animals; Brain-Derived Neurotrophic Factor; Apigenin; Vegetables; Neuroblastoma; Receptor, trkB; Cells, Cultured; Flavones
PubMed: 37101380
DOI: 10.1111/cns.14230 -
International Immunopharmacology Nov 2023Metformin, a first-line drug for type-2 diabetes, displays pleiotropic effects on inflammation, aging, and cancer. Obesity triggers a low-grade chronic inflammation...
Metformin, a first-line drug for type-2 diabetes, displays pleiotropic effects on inflammation, aging, and cancer. Obesity triggers a low-grade chronic inflammation leading to insulin resistance, characterized by increased pro-inflammatory cytokines produced by adipocytes and infiltrated immune cells, which contributes to metabolic syndrome. We investigated metformin's differentiation and immunoregulatory properties of human umbilical cord-mesenchymal stem cells (UC-MSC), as cellular basis of its beneficial role in metabolic dysfunctions. Isolation, characterization and multilineage differentiation of UC-MSC were performed using standard protocols and flow-cytometry. Metformin effects on UC-MSC growth was assessed by colony formation and MTT assay, gene and protein expression by qRT-PCR, and western blot analysis. Proliferation of peripheral blood mononuclear cells (PBMCs) co-cultured with metformin-treated UC-MSC-conditioned media was evaluated by dye dilution assay. We show that metformin decreases proliferation and colony formation of UC-MSCs and enhances their adipogenic lineage commitment. Metformin (3 mM) increases PPARγ and downregulates FABP4 mRNA both in basal and in adipogenic culture conditions; however, the modulation of PPARγ expression is unrelated to the antiproliferative effects. Moreover, metformin inhibits UC-MSC inflammatory activity reducing the expression of IL-6, MCP-1, and COX-2. Conditioned media, collected from metformin-treated UC-MSCs, down-regulate CD3 T lymphocyte growth in stimulated PBMCs and, in particular, reduce the CD8 T cell population. These results indicate that metformin may favor new adipocyte formation and potentiate immune suppressive properties of UC-MSCs. Thus, adipose tissue regeneration and anti-inflammatory activity may represent possible mechanisms by which metformin exerts its positive effect on lipid metabolism.
Topics: Humans; Culture Media, Conditioned; Immunosuppressive Agents; Leukocytes, Mononuclear; Metformin; PPAR gamma; Cell Differentiation; Umbilical Cord; Inflammation; Mesenchymal Stem Cells; Cells, Cultured
PubMed: 37844465
DOI: 10.1016/j.intimp.2023.111078 -
Nature Communications Nov 2023The auditory striatum, a sensory portion of the dorsal striatum, plays an essential role in learning and memory. In contrast to its roles and underlying mechanisms in...
The auditory striatum, a sensory portion of the dorsal striatum, plays an essential role in learning and memory. In contrast to its roles and underlying mechanisms in operant conditioning, however, little is known about its contribution to classical auditory fear conditioning. Here, we reveal the function of the auditory striatum in auditory-conditioned fear memory. We find that optogenetically inhibiting auditory striatal neurons impairs fear memory formation, which is mediated through the striatal-amygdala pathway. Using calcium imaging in behaving mice, we find that auditory striatal neuronal responses to conditioned tones potentiate across memory acquisition and expression. Furthermore, nigrostriatal dopaminergic projections plays an important role in modulating conditioning-induced striatal potentiation. Together, these findings demonstrate the existence of a nigro-striatal-amygdala circuit for conditioned fear memory formation and expression.
Topics: Mice; Animals; Dopamine; Acoustic Stimulation; Amygdala; Learning; Fear
PubMed: 37945595
DOI: 10.1038/s41467-023-43066-9 -
Stem Cell Research & Therapy Jul 2023Mesenchymal stem cells (MSCs) are widely used in a variety of tissue regeneration and clinical trials due to their multiple differentiation potency. However, it remains...
BACKGROUND
Mesenchymal stem cells (MSCs) are widely used in a variety of tissue regeneration and clinical trials due to their multiple differentiation potency. However, it remains challenging to maintain their replicative capability during in vitro passaging while preventing their premature cellular senescence. Forkhead Box P1 (FOXP1), a FOX family transcription factor, has been revealed to regulate MSC cell fate commitment and self-renewal capacity in our previous study.
METHODS
Mass spectra analysis was performed to identify acetylation sites in FOXP1 protein. Single and double knockout mice of FOXP1 and HDAC7 were generated and analyzed with bone marrow MSCs properties. Gene engineering in human embryonic stem cell (hESC)-derived MSCs was obtained to evaluate the impact of FOXP1 key modification on MSC self-renewal potency.
RESULTS
FOXP1 is deacetylated and potentiated by histone deacetylase 7 (HDAC7) in MSCs. FOXP1 and HDAC7 cooperatively sustain bone marrow MSC self-renewal potency while attenuating their cellular senescence. A mutation within human FOXP1 at acetylation site (T176G) homologous to murine FOXP1 T172G profoundly augmented MSC expansion capacity during early passages.
CONCLUSION
These findings reveal a heretofore unanticipated mechanism by which deacetylation of FOXP1 potentiates self-renewal of MSC and protects them from cellular senescence. Acetylation of FOXP1 residue T172 as a critical modification underlying MSC proliferative capacity. We suggest that in vivo gene editing of FOXP1 may provide a novel avenue for manipulating MSC capability during large-scale expansion in clinical trials.
Topics: Animals; Humans; Mice; Cell Differentiation; Cellular Senescence; Forkhead Transcription Factors; Histone Deacetylases; Mesenchymal Stem Cells; Repressor Proteins
PubMed: 37507770
DOI: 10.1186/s13287-023-03376-7 -
Food and Chemical Toxicology : An... Sep 2023Phthalates in contaminated foods and personal care products are one of the most frequently exposed chemicals with a public health concern. Phthalate exposure is related...
Phthalates in contaminated foods and personal care products are one of the most frequently exposed chemicals with a public health concern. Phthalate exposure is related to cardiovascular diseases, including diabetic vascular complications and cerebrovascular diseases, yet the mechanism is still unclear. The blood-brain barrier (BBB) integrity disruption is strongly associated with cardiovascular and neurological disease exacerbation. We investigated BBB damage by di-(2-ethylhexyl) phthalate (DEHP) or its metabolite mono-(2-ethylhexyl) phthalate (MEHP) using brain endothelial cells and rat models. BBB damage by the subthreshold level of MEHP, but not a DEHP, significantly increased by the presence of methylglyoxal (MG), a reactive dicarbonyl compound whose levels increase in the blood in hyperglycemic conditions in diabetic patients. Significant potentiation in apoptosis and autophagy activation, mitochondria-derived reactive oxygen species (ROS) production, and mitochondrial metabolic disturbance were observed in brain ECs by co-exposure to MG and MEHP. N-acetyl cysteine (NAC) restored autophagy activation as well as tight junction protein impairment induced by co-exposure to MG and MEHP. Intraperitoneal administration of MG and MEHP significantly altered mitochondrial membrane potential and tight junction integrity in rat brain endothelium. This study may provide novel insights into enhancing phthalate toxicity in susceptible populations, such as diabetic patients.
Topics: Rats; Animals; Diethylhexyl Phthalate; Pyruvaldehyde; Blood-Brain Barrier; Endothelial Cells; Oxidative Stress; Energy Metabolism; Mitochondria
PubMed: 37572985
DOI: 10.1016/j.fct.2023.113985