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Scientific Reports Jun 2024The oxygen-labile transcription factor called hypoxia-inducible factor (HIF) is responsible for the cellular and organismal adaptive response to reduced oxygen...
The oxygen-labile transcription factor called hypoxia-inducible factor (HIF) is responsible for the cellular and organismal adaptive response to reduced oxygen availability. Deregulation of HIF is associated with the pathogenesis of major human diseases including cardiovascular disease and cancer. Under normoxia, the HIFα subunit is hydroxylated on conserved proline residues within the oxygen-dependent degradation domain (ODD) that labels HIFα for proteasome-mediated degradation. Despite similar oxygen-dependent degradation machinery acting on HIF1α and HIF2α, these two paralogs have been shown to exhibit unique kinetics under hypoxia, which suggests that other regulatory processes may be at play. Here, we characterize the protease activity found in rabbit reticulocytes that specifically cleaves the ODD of HIF1α but not HIF2α. Notably, the cleavage product is observed irrespective of the oxygen-dependent prolyl-hydroxylation potential of HIF1α, suggesting independence from oxygen. HIF1α M561T substitution, which mimics an evolutionary substitution that occurred during the duplication and divergence of HIF1α and HIF2α, diminished the cleavage of HIF1α. Protease inhibitor screening suggests that cysteine proteases cathepsins L and B preferentially cleave HIF1αODD, thereby revealing an additional layer of differential HIF regulation.
Topics: Hypoxia-Inducible Factor 1, alpha Subunit; Animals; Cathepsin L; Proteolysis; Rabbits; Oxygen; Humans; Reticulocytes; Basic Helix-Loop-Helix Transcription Factors; Hydroxylation
PubMed: 38926538
DOI: 10.1038/s41598-024-65537-9 -
Nature Communications Jun 2024Targeted protein degradation (TPD) relies on small molecules to recruit proteins to E3 ligases to induce their ubiquitylation and degradation by the proteasome. Only a...
Targeted protein degradation (TPD) relies on small molecules to recruit proteins to E3 ligases to induce their ubiquitylation and degradation by the proteasome. Only a few of the approximately 600 human E3 ligases are currently amenable to this strategy. This limits the actionable target space and clinical opportunities and thus establishes the necessity to expand to additional ligases. Here we identify and characterize SP3N, a specific degrader of the prolyl isomerase FKBP12. SP3N features a minimal design, where a known FKBP12 ligand is appended with a flexible alkylamine tail that conveys degradation properties. We found that SP3N is a precursor and that the alkylamine is metabolized to an active aldehyde species that recruits the SCF ligase for FKBP12 degradation. Target engagement occurs via covalent adduction of Cys326 in the FBXO22 C-terminal domain, which is critical for ternary complex formation, ubiquitylation and degradation. This mechanism is conserved for two recently reported alkylamine-based degraders of NSD2 and XIAP, thus establishing alkylamine tethering and covalent hijacking of FBXO22 as a generalizable TPD strategy.
Topics: Humans; Proteolysis; Ubiquitination; F-Box Proteins; HEK293 Cells; Tacrolimus Binding Protein 1A; Ubiquitin-Protein Ligases; Amines; Proteasome Endopeptidase Complex; Ligands; Receptors, Cytoplasmic and Nuclear
PubMed: 38926334
DOI: 10.1038/s41467-024-49739-3 -
Journal of Thrombosis and Haemostasis :... Jun 2024During extracorporeal membrane oxygenation (ECMO) support, the high shear stress in the ECMO circuit results in increased proteolysis of von Willebrand Factor (VWF),...
Acquired von Willebrand syndrome during extracorporeal membrane oxygenation support: a comprehensive review of current evidence: Communication from the ISTH SSC on Perioperative and Critical Care Thrombosis and Hemostasis.
During extracorporeal membrane oxygenation (ECMO) support, the high shear stress in the ECMO circuit results in increased proteolysis of von Willebrand Factor (VWF), loss of VWF high molecular weight (HMW) multimers, and impaired ability to bind to platelets and collagen. These structural changes in VWF are consistent with acquired von Willebrand syndrome (AVWS) type 2A and may contribute to the bleeding diathesis frequently observed in ECMO patients. We performed a systematic review of all clinical studies evaluating the prevalence and associated outcomes of AVWS in ECMO patients. Our findings suggest that almost all ECMO patients develop partial or complete loss of VWF HMW multimers within a few hours of device implantation. The AVWS persists as long as the patient is supported by ECMO. Weaning from ECMO rapidly and completely resolves the AVWS. Nevertheless, few studies have reported bleeding outcomes in ECMO patients with AVWS, and the extent to which AVWS contributes to the bleeding diathesis during ECMO support cannot be answered by current evidence. Data supporting the use of VWF concentrates to prevent bleeding complications in ECMO patients remain limited.
PubMed: 38925492
DOI: 10.1016/j.jtha.2024.06.007 -
Journal of Thrombosis and Haemostasis :... Jun 2024Tissue factor pathway inhibitor (TFPI) regulates tissue factor (TF)-triggered coagulation. Humans and mice express transcripts encoding for multi-distributed...
BACKGROUND
Tissue factor pathway inhibitor (TFPI) regulates tissue factor (TF)-triggered coagulation. Humans and mice express transcripts encoding for multi-distributed (endothelial, platelet, and plasma) 3-Kunitz domain TFPIα and endothelial membrane-anchored 2-Kunitz TFPIβ. Mice express a third transcript, γ, that encodes plasma lipoprotein-associated 2-Kunitz TFPI. In humans, proteolysis of α and/or β produces plasma lipoprotein-associated 2-Kunitz TFPI at lower levels. In clinical trials, monoclonal antibodies that target all TFPI isoforms extend coagulation and correct bleeding in hemophilia patients but with some thrombosis risks.
OBJECTIVES
Determine the impact of TFPI isoform-specific deletions on promoting clotting in hemophilia mice.
METHODS
Engineered TFPI isoform-specific, hemophilia (FVIII-null) mice were evaluated for clotting.
RESULTS
Mice expressing any single TFPI isoform are healthy. Thrombin generation assays identified TFPIγ as the dominant anticoagulation isoform in mouse plasma. Hemostasis was assessed by serial bleeding times from a tail vein laceration. Repeatedly, after a clot forms, it is manually disrupted; the number of clots/disruptions occurring over a 15-minute period is reported. C57BL/6 and hemophilia mice clot on average 25.6 versus 5.4 times, respectively. On a hemophilia background, TFPIβ or TFPIγ-specific deletion improves clotting to 14.6 and 15.2 times, respectively (p<0.0001). TFPIα-specific deletion is without impact, clotting 5.1 times. Heterozygous deletion of TFPIβ is effective, clotting 11.8 times (p<0.0001). Heterozygous deletion of TFPIα or TFPIγ alone is ineffective clotting 3.0 and 6.1 times, respectively; but heterozygous TFPIαγ deletion improves clotting to 11.2 times (p<0.001).
CONCLUSION
In hemophilia mice, endothelial TFPIβ and plasma γ-derived 2-Kunitz TFPI individually contribute more to bleeding than total TFPIα.
PubMed: 38925489
DOI: 10.1016/j.jtha.2024.06.006 -
Protein Science : a Publication of the... Jul 2024Although in silico folding based on coevolving residue constraints in the deep-learning era has transformed protein structure prediction, the contributions of coevolving...
Although in silico folding based on coevolving residue constraints in the deep-learning era has transformed protein structure prediction, the contributions of coevolving residues to protein folding, stability, and other functions in physical contexts remain to be clarified and experimentally validated. Herein, the PHD finger module, a well-known histone reader with distinct subtypes containing subtype-specific coevolving residues, was used as a model to experimentally assess the contributions of coevolving residues and to clarify their specific roles. The results of the assessment, including proteolysis and thermal unfolding of wildtype and mutant proteins, suggested that coevolving residues have varying contributions, despite their large in silico constraints. Residue positions with large constraints were found to contribute to stability in one subtype but not others. Computational sequence design and generative model-based energy estimates of individual structures were also implemented to complement the experimental assessment. Sequence design and energy estimates distinguish coevolving residues that contribute to folding from those that do not. The results of proteolytic analysis of mutations at positions contributing to folding were consistent with those suggested by sequence design and energy estimation. Thus, we report a comprehensive assessment of the contributions of coevolving residues, as well as a strategy based on a combination of approaches that should enable detailed understanding of the residue contributions in other large protein families.
Topics: Protein Folding; Models, Molecular; Protein Stability; Proteolysis; Humans
PubMed: 38923615
DOI: 10.1002/pro.5065 -
Small (Weinheim An Der Bergstrasse,... Jun 2024While peptide-based drug development is extensively explored, this strategy has limitations due to rapid excretion from the body (or shorter half-life in the body) and...
While peptide-based drug development is extensively explored, this strategy has limitations due to rapid excretion from the body (or shorter half-life in the body) and vulnerability to protease-mediated degradation. To overcome these limitations, a novel strategy for the development of a peptide-based anticancer agent is introduced, utilizing the conformation switch property of a chameleon sequence stretch (PEP1) derived from a mycobacterium secretory protein, MPT63. The selected peptide is then loaded into a new porous organic polymer (PG-DFC-POP) synthesized using phloroglucinol and a cresol derivative via a condensation reaction to deliver the peptide selectively to cancer cells. Utilizing ensemble and single-molecule approaches, this peptide undergoes a transition from a disordered to an alpha-helical conformation, triggered by the acidic environment within cancer cells that is demonstrated. This adopted alpha-helical conformation resulted in the formation of proteolysis-resistant oligomers, which showed efficient membrane pore-forming activity selectively for negatively charged phospholipids accumulated in cancer cell membranes. The experimental results demonstrated that the peptide-loaded PG-DFC-POP-PEP1 exhibited significant cytotoxicity in cancer cells, leading to cell death through the Pyroptosis pathway, which is established by monitoring numerous associated events starting from lysosome membrane damage to GSDMD-induced cell membrane demolition. This novel conformational switch-based drug design strategy is believed to have great potential in endogenous environment-responsive cancer therapy and the development of future drug candidates to mitigate cancers.
PubMed: 38923392
DOI: 10.1002/smll.202402953 -
Metabolites Jun 2024Food deprivation can occur for different reasons. Fasting (<24 h duration) occurs to meet religious or well-being goals. Starvation (>1-day duration) occurs when there... (Review)
Review
Food deprivation can occur for different reasons. Fasting (<24 h duration) occurs to meet religious or well-being goals. Starvation (>1-day duration) occurs when there is intentional (hunger strike or treatment of a medical condition) or unintentional (anorexia nervosa, drought, epidemic famine, war, or natural disaster) food deprivation. A scoping review was undertaken using the PubMed database to explore 1805 abstracts and review 88 eligible full-text articles to explore the adaptive relationships that emerge between cortisol, insulin, glucagon, and thyroid hormones on the metabolic pathways of macronutrients in humans during fasting and starvation. The collected data indicate that fasting and starvation prime the human body to increase cortisol levels and decrease the insulin/glucagon ratio and triiodothyronine (T) levels. During fasting, increased levels of cortisol and a decreased insulin/glucagon ratio enhance glycogenolysis and reduce the peripheral uptake of glucose and glycogenesis, whereas decreased T levels potentially reduce glycogenolysis. During starvation, increased levels of cortisol and a decreased insulin/glucagon ratio enhance lipolysis, proteolysis, fatty acid and amino acid oxidation, ketogenesis, and ureagenesis, and decreased T levels reduce thermogenesis. We present a potential crosstalk between T and the above hormones, including between T and leptin, to extend their adaptive roles in the metabolism of endogenous macronutrients during food deprivation.
PubMed: 38921471
DOI: 10.3390/metabo14060336 -
Cells Jun 2024Serine/threonine kinase AKT isoforms play a well-established role in cell metabolism and growth. Most pancreatic adenocarcinomas (PDACs) harbor activation mutations of...
Serine/threonine kinase AKT isoforms play a well-established role in cell metabolism and growth. Most pancreatic adenocarcinomas (PDACs) harbor activation mutations of KRAS, which activates the PI3K/AKT signaling pathway. However, AKT inhibitors are not effective in the treatment of pancreatic cancer. To better understand the role of AKT signaling in mutant-KRAS pancreatic tumors, this study utilized proteolysis-targeting chimeras (PROTACs) and CRISPR-Cas9-genome editing to investigate AKT proteins. The PROTAC down-regulation of AKT proteins markedly slowed the growth of three pancreatic tumor cell lines harboring mutant KRAS. In contrast, the inhibition of AKT kinase activity alone had very little effect on the growth of these cell lines. The concurrent genetic deletion of all AKT isoforms (AKT1, AKT2, and AKT3) in the KPC (; ; ) pancreatic cancer cell line also dramatically slowed its growth in vitro and when orthotopically implanted in syngeneic mice. Surprisingly, insulin-like growth factor-1 (IGF-1), but not epidermal growth factor (EGF), restored KPC cell growth in serum-deprived conditions, and the IGF-1 growth stimulation effect was AKT-dependent. The RNA-seq analysis of AKT1/2/3-deficient KPC cells suggested that reduced cholesterol synthesis may be responsible for the decreased response to IGF-1 stimulation. These results indicate that the presence of all three AKT isoforms supports pancreatic tumor cell growth, and the pharmacological degradation of AKT proteins may be more effective than AKT catalytic inhibitors for treating pancreatic cancer.
Topics: Proto-Oncogene Proteins c-akt; Pancreatic Neoplasms; Animals; Cell Line, Tumor; Mice; Humans; Down-Regulation; Proto-Oncogene Proteins p21(ras); Mutation; Cell Proliferation; Signal Transduction; Gene Expression Regulation, Neoplastic
PubMed: 38920688
DOI: 10.3390/cells13121061 -
Drug Design, Development and Therapy 2024Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of... (Review)
Review
Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of evidence indicating that ferroptosis plays a critical role in the advancement of tumors. The increased metabolic activity and higher iron levels in tumor cells make them particularly vulnerable to ferroptosis. As a result, the targeted induction of ferroptosis is becoming an increasingly promising approach for cancer treatment. This review offers an overview of the regulatory mechanisms of ferroptosis, delves into the mechanism of action of traditional small molecule ferroptosis inducers and their effects on various tumors. In addition, the latest progress in inducing ferroptosis using new means such as proteolysis-targeting chimeras (PROTACs), photodynamic therapy (PDT), sonodynamic therapy (SDT) and nanomaterials is summarized. Finally, this review discusses the challenges and opportunities in the development of ferroptosis-inducing agents, focusing on discovering new targets, improving selectivity, and reducing toxic and side effects.
Topics: Ferroptosis; Humans; Neoplasms; Antineoplastic Agents; Photochemotherapy; Animals; Small Molecule Libraries
PubMed: 38919962
DOI: 10.2147/DDDT.S472178 -
The Iowa Orthopaedic Journal 2024Female athletes are at increased risk for anterior cruciate ligament (ACL) injuries. The influence of hormonal variation on female ACL injury risk remains ill-defined....
BACKGROUND
Female athletes are at increased risk for anterior cruciate ligament (ACL) injuries. The influence of hormonal variation on female ACL injury risk remains ill-defined. Recent data suggests that the collagen-degrading menstrual hormone relaxin may cyclically impact female ACL tissue quality. This review aims to identify any correlation between menstrual relaxin peaks and rates of female ACL injury.
METHODS
A systematic review was performed, utilizing the MEDLINE, EMBASE, and CINAHL databases. Included studies had to directly address relaxin/female ACL interactions. The primary outcome variable was relaxin proteolysis of the ACL, at cellular, tissue, joint, and whole-organism levels. The secondary outcome variable was any discussed method of moderating relaxin levels, and the clinical results if available.
RESULTS
AllThe numerous relaxin receptors on female ACLs upregulate local collagenolysis and suppress local collagen production. Peak serum relaxin concentrations (SRC) occur during menstrual cycle days 21-24; a time phase associated with greater risk of ACL injury. Oral contraceptives (OCPs) reduce SRC, with a potential ACLprotective effect.
CONCLUSION
A reasonable correlative and plausible causative relationship exists between peak relaxin levels and increased risk of ACL injury in females, and further investigation is warranted. .
Topics: Humans; Relaxin; Female; Anterior Cruciate Ligament Injuries; Menstrual Cycle; Athletic Injuries; Athletes
PubMed: 38919370
DOI: No ID Found