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Immunology Nov 2023A substantial number of colon cancer patients do not benefit from immunotherapy using programmed cell death 1 (PD1) antibodies. Therefore, combination therapy drugs are...
A substantial number of colon cancer patients do not benefit from immunotherapy using programmed cell death 1 (PD1) antibodies. Therefore, combination therapy drugs are required to improve the efficacy of colon cancer immunotherapy. Recent studies have shown that deubiquitinases are negative regulators of anti-tumour immunity. In the present study, we investigated the effect of the deubiquitinase inhibitor PR-619 in combination with anti-PD1 for the treatment of colorectal cancer. The results revealed that co-treatment with PR-619 and anti-PD1 significantly inhibited tumour growth in tumour-bearing BALB/c mice compared to monotherapy with a single drug. In addition, PR-619/anti-PD1 combined therapy inhibited cell proliferation, promoted cell apoptosis, induced intratumor infiltration of CD8 T cells, and enhanced the release of anti-tumour cytokines. Moreover, PR-619 induced ferroptosis in colon cancer cells, thereby inducing the release of damage-associated molecular patterns that triggered anti-tumour immunity. Finally, we discovered that PR-619 could degrade the GPX4 protein, the high expression of which was associated with poor prognosis and blocked CD8 T cells infiltration in colon cancer. In conclusion, PR-619 may potentiate immunotherapy by inducing ferroptosis, and thereby promoting CD8 T cells-mediated anti-tumour immunity, providing a potential strategy for colon cancer treatment.
PubMed: 37526037
DOI: 10.1111/imm.13683 -
BioRxiv : the Preprint Server For... Apr 2024The hexameric AAA+ disaggregase, Hsp104, collaborates with Hsp70 and Hsp40 via its autoregulatory middle domain (MD) to solubilize aggregated protein conformers....
The hexameric AAA+ disaggregase, Hsp104, collaborates with Hsp70 and Hsp40 via its autoregulatory middle domain (MD) to solubilize aggregated protein conformers. However, how ATP- or ADP-specific MD configurations regulate Hsp104 hexamers remains poorly understood. Here, we define an ATP-specific network of interprotomer contacts between nucleotide-binding domain 1 (NBD1) and MD helix L1, which tunes Hsp70 collaboration. Manipulating this network can: (a) reduce Hsp70 collaboration without enhancing activity; (b) generate Hsp104 hypomorphs that collaborate selectively with class B Hsp40s; (c) produce Hsp70-independent potentiated variants; or (d) create species barriers between Hsp104 and Hsp70. Conversely, ADP-specific intraprotomer contacts between MD helix L2 and NBD1 restrict activity, and their perturbation frequently potentiates Hsp104. Importantly, adjusting the NBD1:MD helix L1 rheostat via rational design enables finely tuned collaboration with Hsp70 to safely potentiate Hsp104, minimize off-target toxicity, and counteract FUS proteinopathy in human cells. Thus, we establish important design principles to tailor Hsp104 therapeutics.
PubMed: 38712168
DOI: 10.1101/2024.04.26.591398 -
MBio Aug 2023Each year, fungi cause more than 1.5 billion infections worldwide and have a devastating impact on human health, particularly in immunocompromised individuals or...
Each year, fungi cause more than 1.5 billion infections worldwide and have a devastating impact on human health, particularly in immunocompromised individuals or patients in intensive care units. The limited antifungal arsenal and emerging multidrug-resistant species necessitate the development of new therapies. One strategy for combating drug-resistant pathogens is the administration of molecules that restore fungal susceptibility to approved drugs. Accordingly, we carried out a screen to identify small molecules that could restore the susceptibility of pathogenic species to azole antifungals. This screening effort led to the discovery of novel 1,4-benzodiazepines that restore fluconazole susceptibility in resistant isolates of , as evidenced by 100-1,000-fold potentiation of fluconazole activity. This potentiation effect was also observed in azole-tolerant strains of and in other pathogenic species. The 1,4-benzodiazepines selectively potentiated different azoles, but not other approved antifungals. A remarkable feature of the potentiation was that the combination of the compounds with fluconazole was fungicidal, whereas fluconazole alone is fungistatic. Interestingly, the potentiators were not toxic to in the absence of fluconazole, but inhibited virulence-associated filamentation of the fungus. We found that the combination of the potentiators and fluconazole significantly enhanced host survival in a model of systemic fungal infection. Taken together, these observations validate a strategy wherein small molecules can restore the activity of highly used anti-infectives that have lost potency. IMPORTANCE In the last decade, we have been witnessing a higher incidence of fungal infections, due to an expansion of the fungal species capable of causing disease (e.g., ), as well as increased antifungal drug resistance. Among human fungal pathogens, species are a leading cause of invasive infections and are associated with high mortality rates. Infections by these pathogens are commonly treated with azole antifungals, yet the expansion of drug-resistant isolates has reduced their clinical utility. In this work, we describe the discovery and characterization of small molecules that potentiate fluconazole and restore the susceptibility of azole-resistant and azole-tolerant isolates. Interestingly, the potentiating 1,4-benzodiazepines were not toxic to fungal cells but inhibited their virulence-associated filamentous growth. Furthermore, combinations of the potentiators and fluconazole decreased fungal burdens and enhanced host survival in a model of systemic fungal infections. Accordingly, we propose the use of novel antifungal potentiators as a powerful strategy for addressing the growing resistance of fungi to clinically approved drugs.
Topics: Humans; Antifungal Agents; Candida; Fluconazole; Azoles; Pharmaceutical Preparations; Microbial Sensitivity Tests; Candida albicans; Mycoses; Drug Resistance, Fungal; Benzodiazepines
PubMed: 37326546
DOI: 10.1128/mbio.00479-23 -
Journal of Medicinal Chemistry Aug 2023() drug resistance poses an alarming threat to global tuberculosis control. We previously reported that , a ring-fused thiazolo-2-pyridone, inhibits respiration,...
() drug resistance poses an alarming threat to global tuberculosis control. We previously reported that , a ring-fused thiazolo-2-pyridone, inhibits respiration, blocks biofilm formation, and restores the activity of the antibiotic isoniazid (INH) in INH-resistant isolates. This discovery revealed a new strategy to address INH resistance. Expanding upon this strategy, we identified C10 analogues with improved potency and drug-like properties. By exploring three heterocycle spacers (oxadiazole, 1,2,3-triazole, and isoxazole) on the ring-fused thiazolo-2-pyridone scaffold, we identified two novel isoxazoles, and . and inhibited respiration and biofilm formation more potently with a broader therapeutic window, were better potentiators of INH-mediated inhibition of an INH-resistant mutant, and more effectively inhibited intracellular replication than . The enantiomer showed further enhanced activity compared to its enantiomer and the racemic mixture. Our potent second-generation analogues offer promise for therapeutic development against drug-resistant .
Topics: Humans; Isoniazid; Mycobacterium tuberculosis; Antitubercular Agents; Drug Resistance, Bacterial; Tuberculosis, Multidrug-Resistant; Isoxazoles; Microbial Sensitivity Tests; Bacterial Proteins
PubMed: 37485869
DOI: 10.1021/acs.jmedchem.3c00358 -
The Journal of General Physiology Jul 2024The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered a...
The TMEM16A calcium-activated chloride channel is a promising therapeutic target for various diseases. Niclosamide, an anthelmintic medication, has been considered a TMEM16A inhibitor for treating asthma and chronic obstructive pulmonary disease (COPD) but was recently found to possess broad-spectrum off-target effects. Here, we show that, under physiological Ca2+ (200-500 nM) and voltages, niclosamide acutely potentiates TMEM16A. 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 clinical applications of niclosamide as a TMEM16A inhibitor. The identification of the putative niclosamide binding site provides insights into the mechanism of TMEM16A pharmacological modulation and provides insights into developing specific TMEM16A modulators to treat human diseases.
Topics: Niclosamide; Anoctamin-1; Animals; Mice; Humans; Vasoconstriction; HEK293 Cells; Binding Sites; Calcium; Mesenteric Arteries; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Male
PubMed: 38814250
DOI: 10.1085/jgp.202313460 -
NeuroImage Aug 2023Physical exercise, even stress-free very-light-intensity exercise such as yoga and very slow running, can have beneficial effects on executive function, possibly by...
Physical exercise, even stress-free very-light-intensity exercise such as yoga and very slow running, can have beneficial effects on executive function, possibly by potentiating prefrontal cortical activity. However, the exact mechanisms underlying this potentiation have not been identified. Evidence from studies using pupillometry demonstrates that pupil changes track the real-time dynamics of activity linked to arousal and attention, including neural circuits from the locus coeruleus to the cortex. This makes it possible to examine whether pupil-linked brain dynamics induced during very-light-intensity exercise mediate benefits to prefrontal executive function in healthy young adults. In this experiment, pupil diameter was measured during 10 min of very-light-intensity exercise (30% V˙o). A Stroop task was used to assess executive function before and after exercise. Prefrontal cortical activation during the task was assessed using multichannel functional near-infrared spectroscopy (fNIRS). We observed that very-light-intensity exercise significantly elicited pupil dilation, reduction of Stroop interference, and task-related left dorsolateral prefrontal cortex activation compared with the resting-control condition. The magnitude of change in pupil dilation predicted the magnitude of improvement in Stroop performance. In addition, causal mediation analysis showed that pupil dilation during very-light-intensity exercise robustly determined subsequent enhancement of Stroop performance. This finding supports our hypothesis that the pupil-linked mechanisms, which may be tied to locus coeruleus activation, are a potential mechanism by which very light exercise enhances prefrontal cortex activation and executive function. It also suggests that pupillometry may be a useful tool to interpret the beneficial impact of exercise on boosting cognition.
Topics: Young Adult; Humans; Pupil; Spectroscopy, Near-Infrared; Cognition; Executive Function; Exercise; Prefrontal Cortex
PubMed: 37353097
DOI: 10.1016/j.neuroimage.2023.120244 -
GeroScience Apr 2024As we age, the ability to regenerate and repair skeletal muscle damage declines, partially due to increasing dysfunction of muscle resident stem cells-satellite cells...
As we age, the ability to regenerate and repair skeletal muscle damage declines, partially due to increasing dysfunction of muscle resident stem cells-satellite cells (SC). Recent evidence implicates cellular senescence, which is the irreversible arrest of proliferation, as a potentiator of SC impairment during aging. However, little is known about the role of senescence in SC, and there is a large discrepancy in senescence classification within skeletal muscle. The purpose of this study was to develop a model of senescence in skeletal muscle myoblasts and identify how common senescence-associated biomarkers respond. Low-passage CC myoblasts were treated with bleomycin or vehicle and then evaluated for cytological and molecular senescence markers, proliferation status, cell cycle kinetics, and differentiation potential. Bleomycin treatment caused double-stranded DNA breaks, which upregulated p21 mRNA and protein, potentially through NF-κB and senescence-associated super enhancer (SASE) signaling (p < 0.01). Consequently, cell proliferation was abruptly halted due to G2/M-phase arrest (p < 0.01). Bleomycin-treated myoblasts displayed greater senescence-associated β-galactosidase staining (p < 0.01), which increased over several days. These myoblasts remained senescent following 6 days of differentiation and had significant impairments in myotube formation (p < 0.01). Furthermore, our results show that senescence can be maintained despite the lack of p16 gene expression in CC myoblasts. In conclusion, bleomycin treatment provides a valid model of damage-induced senescence that was associated with elevated p21, reduced myoblast proliferation, and aberrant cell cycle kinetics, while confirming that a multi-marker approach is needed for the accurate classification of senescence within skeletal muscle.
Topics: Bleomycin; Cell Line; Cellular Senescence; Cell Differentiation; Myoblasts; Biomarkers
PubMed: 37751045
DOI: 10.1007/s11357-023-00929-9 -
Biomaterials Oct 2023Nanocarrier-assisted sonodynamic therapy (SDT) has shown great potential for the effective and targeted treatment of deep-seated tumors by overcoming the critical...
Bioreducible exosomes encapsulating glycolysis inhibitors potentiate mitochondria-targeted sonodynamic cancer therapy via cancer-targeted drug release and cellular energy depletion.
Nanocarrier-assisted sonodynamic therapy (SDT) has shown great potential for the effective and targeted treatment of deep-seated tumors by overcoming the critical limitations of sonosensitizers. However, in vivo SDT using nanocarriers is still constrained by their intrinsic toxicity and nonspecific cargo release. In this study, we developed bioreducible exosomes for the safe and tumor-specific delivery of mitochondria-targeting sonosensitizers [triphenylphosphonium-conjugated chlorin e6 (T-Ce6)] and glycolysis inhibitors (FX11). Redox-cleavable diselenide linker-bearing lipids were embedded into exosomes to trigger drug release in response to overexpressed glutathione in the tumor microenvironment. Bioreducible exosomes facilitate the cytoplasmic release of their payload in the reducing environment of tumor cells. They significantly enhance drug release and sonodynamic effects when irradiated with ultrasound (US). The mitochondria-targeted accumulation of T-Ce6 efficiently damaged the mitochondria of the cells under US irradiation, accelerating apoptotic cell death. FX11 substantially inhibited cellular energy metabolism, potentiating the antitumor efficacy of mitochondria-targeted SDT. Bioreducible exosomes effectively suppressed tumor growth in mice without significant systemic toxicity, via a combination of mitochondria-targeted SDT and energy metabolism-targeted therapy. This study offers new insights into the use of dual stimuli-responsive exosomes encapsulating sonosensitizers for safe and targeted sonodynamic cancer therapy.
Topics: Animals; Mice; Exosomes; Drug Liberation; Cell Line, Tumor; Neoplasms; Antineoplastic Agents; Mitochondria; Porphyrins; Glycolysis; Reactive Oxygen Species; Tumor Microenvironment
PubMed: 37473534
DOI: 10.1016/j.biomaterials.2023.122242 -
Membranes Jul 2023The macrolide polyene antibiotic amphotericin B (AmB), remains a valuable drug to treat systemic mycoses due to its wide antifungal activity and low probability of...
The macrolide polyene antibiotic amphotericin B (AmB), remains a valuable drug to treat systemic mycoses due to its wide antifungal activity and low probability of developing resistance. The high toxicity of AmB, expressed in nephropathy and hemolysis, could be partially resolved by lowering therapeutic AmB concentration while maintaining efficacy. This work discusses the possibility of using plant polyphenols and alkaloids to enhance the pore-forming and consequently antifungal activity of AmB. We demonstrated that phloretin, phlorizin, naringenin, taxifolin, quercetin, biochanin A, genistein, resveratrol, and quinine led to an increase in the integral AmB-induced transmembrane current in the bilayers composed of palmitoyloleoylphosphocholine and ergosterol, while catechin, colchicine, and dihydrocapsaicin did not practically change the AmB activity. Cardamonin, 4'-hydroxychalcone, licochalcone A, butein, curcumin, and piperine inhibited AmB-induced transmembrane current. Absorbance spectroscopy revealed no changes in AmB membrane concentration with phloretin addition. A possible explanation of the potentiation is related to the phytochemical-produced changes in the elastic membrane properties and the decrease in the energy of formation of the lipid mouth of AmB pores, which is partially confirmed by differential scanning microcalorimetry. The possibility of AmB interaction with cholesterol in the mammalian cell membranes instead of ergosterol in fungal membranes, determines its high toxicity. The replacement of ergosterol with cholesterol in the membrane lipid composition led to a complete loss or a significant decrease in the potentiating effects of tested phytochemicals, indicating low potential toxicity of these compounds and high therapeutic potential of their combinations with the antibiotic. The discovered combinations of AmB with plant molecules that enhance its pore-forming ability in ergosterol-enriched membranes, seem to be promising for further drug development in terms of the toxicity decrease and efficacy improvement.
PubMed: 37505036
DOI: 10.3390/membranes13070670 -
Journal of Political Power 2023This paper explicates the concept of (AR) and its connection to sociopolitical change, drawing from resistance studies' frameworks. Combining semi-structured and...
This paper explicates the concept of (AR) and its connection to sociopolitical change, drawing from resistance studies' frameworks. Combining semi-structured and integrative reviews of literature on resistance in art and aesthetics across the humanities and social sciences, the paper performs a thematic analysis to identify patterns in AR's definitions, modes and domains, attributes, and transformative variables. These are synthesized in terms of the evolving resistance studies' frameworks and an understanding of aesthetics as relating to the sensorium, ultimately revealing three interlocking issues: (1) publicness, (2) potentiality, and (3) plexus. These AR-specific issues contribute to the categorization of resistance, its identification, and the tracing of its network en route to change.
PubMed: 38013878
DOI: 10.1080/2158379X.2023.2245228