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JCI Insight Aug 2023Proline and its synthesis enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) are implicated in epithelial-mesenchymal transition (EMT), yet how proline and PYCR1...
Proline and its synthesis enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) are implicated in epithelial-mesenchymal transition (EMT), yet how proline and PYCR1 function in allergic asthmatic airway remodeling via EMT has not yet been addressed to our knowledge. In the present study, increased levels of plasma proline and PYCR1 were observed in patients with asthma. Similarly, proline and PYCR1 in lung tissues were high in a murine allergic asthma model induced by house dust mites (HDMs). Pycr1 knockout decreased proline in lung tissues, with reduced airway remodeling and EMT. Mechanistically, loss of Pycr1 restrained HDM-induced EMT by modulating mitochondrial fission, metabolic reprogramming, and the AKT/mTORC1 and WNT3a/β-catenin signaling pathways in airway epithelial cells. Therapeutic inhibition of PYCR1 in wild-type mice disrupted HDM-induced airway inflammation and remodeling. Deprivation of exogenous proline relieved HDM-induced airway remodeling to some extent. Collectively, this study illuminates that proline and PYCR1 involved with airway remodeling in allergic asthma could be viable targets for asthma treatment.
Topics: Animals; Mice; Airway Remodeling; Proline; Asthma; Lung; Hypersensitivity
PubMed: 37432745
DOI: 10.1172/jci.insight.167395 -
Nature Communications Sep 2023Endothelial dysfunction represents a major cardiovascular risk factor for hypertension. Sp1 and Sp3 belong to the specificity protein and Krüppel-like transcription...
Endothelial dysfunction represents a major cardiovascular risk factor for hypertension. Sp1 and Sp3 belong to the specificity protein and Krüppel-like transcription factor families. They are ubiquitously expressed and closely associated with cardiovascular development. We investigate the role of Sp1 and Sp3 in endothelial cells in vivo and evaluate whether captopril, an angiotensin-converting enzyme inhibitor (ACEI), targets Sp1/Sp3 to exert its effects. Inducible endothelial-specific Sp1/Sp3 knockout mice are generated to elucidate their role in endothelial cells. Tamoxifen-induced deletion of endothelial Sp1 and Sp3 in male mice decreases the serum nitrite/nitrate level, impairs endothelium-dependent vasodilation, and causes hypertension and cardiac remodeling. The beneficial actions of captopril are abolished by endothelial-specific deletion of Sp1/Sp3, indicating that they may be targets for ACEIs. Captopril increases Sp1/Sp3 protein levels by recruiting histone deacetylase 1, which elevates deacetylation and suppressed degradation of Sp1/Sp3. Sp1/Sp3 represents innovative therapeutic target for captopril to prevent cardiovascular diseases.
Topics: Male; Animals; Mice; Blood Pressure; Captopril; Endothelial Cells; Hypertension; Mice, Knockout; Endothelium
PubMed: 37735515
DOI: 10.1038/s41467-023-41567-1 -
Nature Cell Biology Jul 2023The prolyl hydroxylation of hypoxia-inducible factor 1α (HIF-1α) mediated by the EGLN-pVHL pathway represents a classic signalling mechanism that mediates cellular...
The prolyl hydroxylation of hypoxia-inducible factor 1α (HIF-1α) mediated by the EGLN-pVHL pathway represents a classic signalling mechanism that mediates cellular adaptation under hypoxia. Here we identify RIPK1, a known regulator of cell death mediated by tumour necrosis factor receptor 1 (TNFR1), as a target of EGLN1-pVHL. Prolyl hydroxylation of RIPK1 mediated by EGLN1 promotes the binding of RIPK1 with pVHL to suppress its activation under normoxic conditions. Prolonged hypoxia promotes the activation of RIPK1 kinase by modulating its proline hydroxylation, independent of the TNFα-TNFR1 pathway. As such, inhibiting proline hydroxylation of RIPK1 promotes RIPK1 activation to trigger cell death and inflammation. Hepatocyte-specific Vhl deficiency promoted RIPK1-dependent apoptosis to mediate liver pathology. Our findings illustrate a key role of the EGLN-pVHL pathway in suppressing RIPK1 activation under normoxic conditions to promote cell survival and a model by which hypoxia promotes RIPK1 activation through modulating its proline hydroxylation to mediate cell death and inflammation in human diseases, independent of TNFR1.
Topics: Humans; Receptors, Tumor Necrosis Factor, Type I; Hydroxylation; Necroptosis; Hypoxia; Proline; Inflammation; Hypoxia-Inducible Factor 1, alpha Subunit; Receptor-Interacting Protein Serine-Threonine Kinases
PubMed: 37400498
DOI: 10.1038/s41556-023-01170-4 -
Cell Death and Differentiation Aug 2023Solute carrier family 25 member 51 (SLC25A51) was recently identified as the mammalian mitochondrial NAD+ transporter essential for mitochondria functions. However, the...
Solute carrier family 25 member 51 (SLC25A51) was recently identified as the mammalian mitochondrial NAD+ transporter essential for mitochondria functions. However, the role of SLC25A51 in human disease, such as cancer, remains undefined. Here, we report that SLC25A51 is upregulated in multiple cancers, which promotes cancer cells proliferation. Loss of SLC25A51 elevates the mitochondrial proteins acetylation levels due to SIRT3 dysfunctions, leading to the impairment of P5CS enzymatic activity, which is the key enzyme in proline biogenesis, and the reduction in proline contents. Notably, we find fludarabine phosphate, an FDA-approved drug, is able to bind with and inhibit SLC25A51 functions, causing mitochondrial NAD decrease and proteins hyperacetylation, which could further synergize with aspirin to reinforce the anti-tumor efficacy. Our study reveals that SLC25A51 is an attractive anti-cancer target, and provides a novel drug combination of fludarabine phosphate with aspirin as a potential cancer therapy strategy.
Topics: Animals; Humans; Acetylation; Proline; Mitochondria; Sirtuin 3; Homeostasis; Mammals
PubMed: 37419986
DOI: 10.1038/s41418-023-01185-2 -
Clinical Infectious Diseases : An... Nov 2023Nirmatrelvir-ritonavir is currently not recommended in patients with an estimated glomerular filtration rate (eGFR) <30 mL/minute/1.73 m2.
BACKGROUND
Nirmatrelvir-ritonavir is currently not recommended in patients with an estimated glomerular filtration rate (eGFR) <30 mL/minute/1.73 m2.
METHODS
To determine the safety profile and clinical and virological outcomes of nirmatrelvir-ritonavir use at a modified dosage in adults with chronic kidney disease (CKD), a prospective, single-arm, interventional trial recruited patients with eGFR <30 mL/minute/1.73 m2 and on dialysis. Primary outcomes included safety profile, adverse/serious adverse events, and events leading to drug discontinuation. Disease symptoms, virological outcomes by serial severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral polymerase chain reaction (PCR) tests, rapid antigen tests, and virological and symptomatic rebound were also recorded.
RESULTS
Fifty-nine (69.4%) of the 85 participants had stage 5 CKD and were on dialysis. Eighty (94.1%) completed the full treatment course; 9.4% and 5.9% had adverse and serious adverse events, and these were comparable between those with eGFR < or >30 mL/minute/1.73 m2. The viral load significantly decreased on days 5, 15, and 30 (P < .001 for all), and the reduction was consistent in the subgroup with eGFR <30 mL/minute/1.73 m2. Ten patients had virological rebound, which was transient and asymptomatic.
CONCLUSIONS
Among patients with CKD, a modified dose of nirmatrelvir-ritonavir is a well-tolerated therapy in mild COVID-19 as it can effectively suppress the SARS-CoV-2 viral load with a favorable safety profile. Virological and symptomatic rebound, although transient with low infectivity, may occur after treatment. Nirmatrelvir-ritonavir should be considered for use in patients with CKD, including stage 5 CKD on dialysis. Clinical Trials Registration. Clinical Trials.gov; identifier: NCT05624840.
Topics: Adult; Humans; COVID-19; SARS-CoV-2; Prospective Studies; Ritonavir; COVID-19 Drug Treatment; Renal Insufficiency, Chronic; Kidney Failure, Chronic; Antiviral Agents; Lactams; Leucine; Nitriles; Proline
PubMed: 37531093
DOI: 10.1093/cid/ciad371 -
Nature Oct 2023Nirmatrelvir is a specific antiviral drug that targets the main protease (M) of SARS-CoV-2 and has been approved to treat COVID-19. As an RNA virus characterized by high...
Nirmatrelvir is a specific antiviral drug that targets the main protease (M) of SARS-CoV-2 and has been approved to treat COVID-19. As an RNA virus characterized by high mutation rates, whether SARS-CoV-2 will develop resistance to nirmatrelvir is a question of concern. Our previous studies have shown that several mutational pathways confer resistance to nirmatrelvir, but some result in a loss of viral replicative fitness, which is then compensated for by additional alterations. The molecular mechanisms for this observed resistance are unknown. Here we combined biochemical and structural methods to demonstrate that alterations at the substrate-binding pocket of M can allow SARS-CoV-2 to develop resistance to nirmatrelvir in two distinct ways. Comprehensive studies of the structures of 14 M mutants in complex with drugs or substrate revealed that alterations at the S1 and S4 subsites substantially decreased the level of inhibitor binding, whereas alterations at the S2 and S4' subsites unexpectedly increased protease activity. Both mechanisms contributed to nirmatrelvir resistance, with the latter compensating for the loss in enzymatic activity of the former, which in turn accounted for the restoration of viral replicative fitness, as observed previously. Such a profile was also observed for ensitrelvir, another clinically relevant M inhibitor. These results shed light on the mechanisms by which SARS-CoV-2 evolves to develop resistance to the current generation of protease inhibitors and provide the basis for the design of next-generation M inhibitors.
Topics: Humans; Antiviral Agents; COVID-19; Lactams; Leucine; Nitriles; SARS-CoV-2; Drug Resistance, Viral; Binding Sites; Mutation; Substrate Specificity; Coronavirus 3C Proteases; Virus Replication; Drug Design; Proline
PubMed: 37696289
DOI: 10.1038/s41586-023-06609-0 -
Clinical Therapeutics Mar 2024
Topics: Humans; Ritonavir; Lactams; Leucine; Nitriles; Proline; Antiviral Agents
PubMed: 38458901
DOI: 10.1016/j.clinthera.2024.02.004 -
Current Opinion in Biotechnology Dec 2023Proline is a nonessential amino acid, and its metabolism has been implicated in numerous malignancies. Together with a direct role in regulating cancer cells'... (Review)
Review
Proline is a nonessential amino acid, and its metabolism has been implicated in numerous malignancies. Together with a direct role in regulating cancer cells' proliferation and survival, proline metabolism plays active roles in shaping the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) display high rates of proline biosynthesis to support the production of collagen for the extracellular matrix (ECM). Indeed, impaired proline metabolism in CAFs results in reduced collagen deposition and compromises the growth and metastatic spread of cancer. Moreover, the rate of proline metabolism regulates intracellular reactive oxygen species (ROS) levels, which influence the production and release of cytokines from cancer cells, contributing toward an immune-permissive TME. Hence, targeting proline metabolism is a promising anticancer strategy that could improve patients' outcome and response to immunotherapy.
Topics: Humans; Immune Evasion; Neoplasms; Collagen; Extracellular Matrix; Proline; Tumor Microenvironment
PubMed: 37864905
DOI: 10.1016/j.copbio.2023.103011 -
The Journal of Clinical Investigation Dec 2023Cell lineage plasticity is one of the major causes for the failure of targeted therapies in various cancers. However, the driver and actionable drug targets in promoting...
Cell lineage plasticity is one of the major causes for the failure of targeted therapies in various cancers. However, the driver and actionable drug targets in promoting cancer cell lineage plasticity are scarcely identified. Here, we found that a G protein-coupled receptor, ADORA2A, is specifically upregulated during neuroendocrine differentiation, a common form of lineage plasticity in prostate cancer and lung cancer following targeted therapies. Activation of the ADORA2A signaling rewires the proline metabolism via an ERK/MYC/PYCR cascade. Increased proline synthesis promotes deacetylases SIRT6/7-mediated deacetylation of histone H3 at lysine 27 (H3K27), and thereby biases a global transcriptional output toward a neuroendocrine lineage profile. Ablation of Adora2a in genetically engineered mouse models inhibits the development and progression of neuroendocrine prostate and lung cancers, and, intriguingly, prevents the adenocarcinoma-to-neuroendocrine phenotypic transition. Importantly, pharmacological blockade of ADORA2A profoundly represses neuroendocrine prostate and lung cancer growth in vivo. Therefore, we believe that ADORA2A can be used as a promising therapeutic target to govern the epigenetic reprogramming in neuroendocrine malignancies.
Topics: Animals; Humans; Male; Mice; Cell Line, Tumor; Epigenesis, Genetic; Lung Neoplasms; Proline; Prostate; Prostatic Neoplasms; Sirtuins
PubMed: 38099497
DOI: 10.1172/JCI168670 -
Science Advances Sep 2023Previous studies have revealed a role for proline metabolism in supporting cancer development and metastasis. In this study, we show that many cancer cells respond to...
Previous studies have revealed a role for proline metabolism in supporting cancer development and metastasis. In this study, we show that many cancer cells respond to loss of attachment by accumulating and secreting proline. Detached cells display reduced proliferation accompanied by a general decrease in overall protein production and de novo amino acid synthesis compared to attached cells. However, proline synthesis was maintained under detached conditions. Furthermore, while overall proline incorporation into proteins was lower in detached cells compared to other amino acids, there was an increased production of the proline-rich protein collagen. The increased excretion of proline from detached cells was also shown to be used by macrophages, an abundant and important component of the tumor microenvironment. Our study suggests that detachment induced accumulation and secretion of proline may contribute to tumor progression by supporting increased production of extracellular matrix and providing proline to surrounding stromal cells.
Topics: Proline; Amino Acids; Biological Transport; Extracellular Matrix; Macrophages; Neoplasms
PubMed: 37672588
DOI: 10.1126/sciadv.adh2023