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Cancers Apr 2022In maturing sperm cells, a major genome re-organization takes place, which includes a global increase in the acetylation of histones prior to their replacement by... (Review)
Review
In maturing sperm cells, a major genome re-organization takes place, which includes a global increase in the acetylation of histones prior to their replacement by protamines, the latter being responsible for the tight packaging of the male genome. Understanding the function of the oncogenic BRD4-NUT fusion protein in NUT carcinoma (NC) cells has proven to be essential in uncovering the mechanisms underlying histone hyperacetylation in spermatogenic cells. Indeed, these studies have revealed the mechanism by which a cooperation between BRD4, a bromodomain factor of the BET family, NUT, a normally testis-specific factor, and the histone acetyltransferase p300, induces the generation of hyperacetylated chromatin domains which are present in NC cells. The generation of ko mice enabled us to demonstrate a genetic interaction between and , encoding BRDT, a testis-specific BRD4-like factor. Indeed, in spermatogenic cells, NUT and p300 interact, which results in an increased acetylation of histone H4 at both positions K5 and K8. These two positions, when both acetylated, are specifically recognized by the first bromodomain of BRDT, which then mediates the removal of histone and their replacement by protamines. Taken together, these investigations show that the fusion of NUT to BRD4 in NUT Carcinoma cells reconstitutes, in somatic cells, a functional loop, which normally drives histone hyperacetylation and chromatin binding by a BET factor in spermatogenic cells.
PubMed: 35565363
DOI: 10.3390/cancers14092234 -
The Journal of Thoracic and... Oct 2015
Topics: Antibodies; Anticoagulants; Cardiopulmonary Bypass; Female; Heparin; Heparin Antagonists; Humans; Male; Platelet Activation; Protamines
PubMed: 26320779
DOI: 10.1016/j.jtcvs.2015.08.003 -
Clinical Cardiology Jan 2023Despite major advances, transcatheter aortic valve replacement (TAVR) is still associated with procedure-specific complications. Although previous studies reported lower...
BACKGROUND
Despite major advances, transcatheter aortic valve replacement (TAVR) is still associated with procedure-specific complications. Although previous studies reported lower bleeding rates in patients receiving protamine for heparin reversal, the optimal protamine-to-heparin dosing ratio is unknown.
HYPOTHESIS
The aim of this study was a comparison of two different heparin antagonization regimens for the prevention of bleeding complications after TAVR.
METHODS
The study included 1446 patients undergoing TAVR, of whom 623 received partial and 823 full heparin antagonization. The primary endpoint was a composite of 30-day mortality, life-threatening, and major bleeding. Safety endpoints included stroke and myocardial infarction at 30 days.
RESULTS
Full antagonization of heparin resulted in lower rates of the primary endpoint as compared to partial heparin reversal (5.6% vs. 10.4%, p < .01), which was mainly driven by lower rates of life-threatening (0.5% vs. 1.6%, p = .05) and major bleeding (3.2% vs. 7.5%, p < .01). Moreover, the incidence of major vascular complications was significantly lower in patients with full heparin reversal (3.5% vs. 7.5%, p < .01). The need for red-blood-cell transfusion was lower in patients receiving full as compared to partial heparin antagonization (10.4% vs. 15.9%, p < .01). No differences were observed in the incidence of stroke and myocardial infarction between patients with full and partial heparin reversal (2.2% vs. 2.6%, p = .73 and 0.2% vs. 0.4%, p = .64, respectively).
CONCLUSIONS
Full heparin antagonization resulted in significantly lower rates of life-threatening and major bleeding after TAVR as compared to partial heparin reversal. The occurrence of stroke and myocardial infarction was low and comparable between both groups.
Topics: Humans; Heparin; Transcatheter Aortic Valve Replacement; Protamines; Aortic Valve Stenosis; Risk Factors; Treatment Outcome; Hemorrhage; Stroke; Myocardial Infarction; Aortic Valve
PubMed: 36259730
DOI: 10.1002/clc.23936 -
Cureus Feb 2024The conventional method of heparin and protamine management during cardiopulmonary bypass (CPB) is based on total body weight which fails to account for the... (Review)
Review
BACKGROUND
The conventional method of heparin and protamine management during cardiopulmonary bypass (CPB) is based on total body weight which fails to account for the heterogeneous response to heparin in each patient. On the other hand, the literature is inconclusive on whether individualized anticoagulation management based on real-time blood heparin concentration improves post-CBP outcomes.
METHODS
We searched databases of Medline, Excerpta Medica dataBASE (EMBASE), PubMed, Cumulative Index to Nursing and Allied Health Literature (CINHL), and Google Scholar, recruiting randomized controlled trials (RCTs) and prospective studies comparing the outcomes of dosing heparin and/or protamine based on measured heparin concentration versus patient's total body weight for CPB. Random effects meta-analyses and meta-regression were conducted to compare the outcome profiles. Primary endpoints include postoperative blood loss and the correlation with heparin and protamine doses, the reversal protamine and loading heparin dose ratio; secondary endpoints included postoperative platelet counts, antithrombin III, fibrinogen levels, activated prothrombin time (aPTT), incidences of heparin rebound, and re-exploration of chest wound for bleeding.
RESULTS
Twenty-six studies, including 22 RCTs and four prospective cohort studies involving 3,810 patients, were included. Compared to body weight-based dosing, patients of individualized, heparin concentration-based group had significantly lower postoperative blood loss (mean difference (MD)=49.51 mL, 95% confidence interval (CI): 5.33-93.71), lower protamine-to-heparin dosing ratio (MD=-0.20, 95% CI: -0.32 ~ -0.12), and higher early postoperative platelet counts (MD=8.83, 95% CI: 2.07-15.59). The total heparin doses and protamine reversal were identified as predictors of postoperative blood loss by meta-regression.
CONCLUSIONS
There was a significant correlation between the doses of heparin and protamine with postoperative blood loss; therefore, précised dosing of both could be critical for reducing bleeding and transfusion requirements. Data from the enrolled studies indicated that compared to conventional weight-based dosing, individualized, blood concentration-based heparin and protamine dosing may have outcome benefits reducing postoperative blood loss. The dosing calculation of heparin based on the assumption of a one-compartment pharmacokinetic/pharmacodynamic (PK/PD) model and linear relationship between the calculated dose and blood heparin concentration may be inaccurate. With the recent advancement of the technologies of machine learning, individualized, precision management of anticoagulation for CPB may be possible in the near future.
PubMed: 38357407
DOI: 10.7759/cureus.54144 -
PLoS Genetics Jun 2022Protamines are unique sperm-specific proteins that package and protect paternal chromatin until fertilization. A subset of mammalian species expresses two protamines...
Protamines are unique sperm-specific proteins that package and protect paternal chromatin until fertilization. A subset of mammalian species expresses two protamines (PRM1 and PRM2), while in others PRM1 is sufficient for sperm chromatin packaging. Alterations of the species-specific ratio between PRM1 and PRM2 are associated with infertility. Unlike PRM1, PRM2 is generated as a precursor protein consisting of a highly conserved N-terminal domain, termed cleaved PRM2 (cP2), which is consecutively trimmed off during chromatin condensation. The carboxyterminal part, called mature PRM2 (mP2), interacts with DNA and together with PRM1, mediates chromatin-hypercondensation. The removal of the cP2 domain is believed to be imperative for proper chromatin condensation, yet, the role of cP2 is not yet understood. We generated mice lacking the cP2 domain while the mP2 is still expressed. We show that the cP2 domain is indispensable for complete sperm chromatin protamination and male mouse fertility. cP2 deficient sperm show incomplete protamine incorporation and a severely altered protamine ratio, retention of transition proteins and aberrant retention of the testis specific histone variant H2A.L.2. During epididymal transit, cP2 deficient sperm seem to undergo ROS mediated degradation leading to complete DNA fragmentation. The cP2 domain therefore seems to be a key aspect in the complex crosstalk between histones, transition proteins and protamines during sperm chromatin condensation. Overall, we present the first step towards understanding the role of the cP2 domain in paternal chromatin packaging and open up avenues for further research.
Topics: Animals; Chromatin; Histones; Humans; Infertility, Male; Male; Mammals; Mice; Protamines; Semen; Spermatozoa
PubMed: 35763544
DOI: 10.1371/journal.pgen.1010272 -
Biology of Reproduction Nov 2021While an E3 ubiquitin ligase, RNF8, was initially reported to be required for histone-to-protamine exchange in spermiogenesis, we subsequently demonstrated that RNF8 is...
While an E3 ubiquitin ligase, RNF8, was initially reported to be required for histone-to-protamine exchange in spermiogenesis, we subsequently demonstrated that RNF8 is not involved in this process. Nevertheless, reflecting a lingering misunderstanding in the field, a growing number of studies have continued to postulate a requirement for RNF8 in the histone-to-protamine exchange. For example, a recent study claimed that a mouse PIWI protein, MIWI, controls RNF8-mediated histone-to-protamine exchange. Here, confirming our earlier conclusions, we show that RNF8 is required neither for the establishment of histone H4K16 acetylation, which is an initial step in histone removal during spermiogenesis, nor for the incorporation of two protamine proteins, PRM1 and PRM2. Thus, whereas RNF8 mediates ubiquitination of H2A on the sex chromosomes in meiosis, during the prior stage of spermatogenesis, our genetic evidence underscores that RNF8 is not involved in histone-to-protamine exchange.
Topics: Acetylation; Animals; Biological Transport; Chromatin Assembly and Disassembly; Histones; Mice; Mice, Knockout; Protamines; Sex Chromosomes; Spermatogenesis; Ubiquitin-Protein Ligases; Ubiquitination
PubMed: 34225362
DOI: 10.1093/biolre/ioab132 -
Indian Journal of Endocrinology and... 2016This communication explores the concept of flexibility, a propos insulin preparations and insulin regimes used in the management of type 2 diabetes. The flexibility of...
This communication explores the concept of flexibility, a propos insulin preparations and insulin regimes used in the management of type 2 diabetes. The flexibility of an insulin regime or preparation is defined as their ability to be injected at variable times, with variable injection-meal time gaps, in a dose frequency and quantum determined by shared decision making, with a minimal requirement of glucose monitoring and health professional consultation, with no compromise on safety, efficiency and tolerability. The relative flexibility of various basal, prandial and dual action insulins, as well as intensive regimes, is compared. The biopsychosocial model of health is used to assess the utility of different insulins while encouraging a philosophy of flexible insulin usage.
PubMed: 27186563
DOI: 10.4103/2230-8210.180003 -
Cell & Bioscience Aug 2022As a member of RNA-binding protein, CDKN2AIP has been shown to play a critical role in stem cell pluripotency and somatic differentiation. Recent studies indicate that...
BACKGROUND
As a member of RNA-binding protein, CDKN2AIP has been shown to play a critical role in stem cell pluripotency and somatic differentiation. Recent studies indicate that Cdkn2aip is essential for spermatogonial self-renewal and proliferation through the activating Wnt-signaling pathway. However, the mechanisms of how Cdkn2aip regulate spermatogenesis is poorly characterized.
RESULTS
We discovered that the CDKN2AIP was expressed in spermatocyte as well as spermatids and participated in spermiogenesis. Cdkn2aip mice exhibited multiple sperm head defects accompanied by age dependent germ cell loss that might be result of protamine replacement failure and impaired SUN1 expression. Loss of Cdkn2aip expression in male mice resulted in synapsis failure in 19% of all spermatocytes and increased apoptosis due to damaged DNA double-strand break (DSB) repair and crossover formation. In vitro, knockdown of Cdkn2aip was associated with extended S phase, increased DNA damage and apoptosis.
CONCLUSIONS
Our findings not only identified the importance of CDKN2AIP in spermiogenesis and germ cell development, but also provided insight upon the driving mechanism.
PubMed: 35989335
DOI: 10.1186/s13578-022-00861-z -
Frontiers in Cell and Developmental... 2018The past decade has seen a tremendous increase in interest and progress in the field of sperm epigenetics. Studies have shown that chromatin regulation during male... (Review)
Review
The past decade has seen a tremendous increase in interest and progress in the field of sperm epigenetics. Studies have shown that chromatin regulation during male germline development is multiple and complex, and that the spermatozoon possesses a unique epigenome. Its DNA methylation profile, DNA-associated proteins, nucleo-protamine distribution pattern and non-coding RNA set up a unique epigenetic landscape which is delivered, along with its haploid genome, to the oocyte upon fertilization, and therefore can contribute to embryogenesis and to the offspring health. An emerging body of compelling data demonstrates that environmental exposures and paternal lifestyle can change the sperm epigenome and, consequently, may affect both the embryonic developmental program and the health of future generations. This short review will attempt to provide an overview of what is currently known about sperm epigenome and the existence of transgenerational epigenetic inheritance of paternally acquired traits that may contribute to the offspring phenotype.
PubMed: 29868581
DOI: 10.3389/fcell.2018.00050 -
BioMed Research International 2018We aimed to evaluate bone response and apatite formation to titanium (Ti) implants, coated with double-stranded DNA (DNA-d) or single-stranded DNA (DNA-s), and to...
We aimed to evaluate bone response and apatite formation to titanium (Ti) implants, coated with double-stranded DNA (DNA-d) or single-stranded DNA (DNA-s), and to compare the influence in different structure of DNA, double strand and single strand on bone response and apatite formation. The bone responses to multilayered DNA-d/protamine or DNA-s/protamine coating implants were evaluated after implantation into the extracted sockets of rat maxillary molars. Apatite formation on either coating surface after immersion in simulated body fluid (SBF) was evaluated using the quartz crystal microbalance (QCM) method. DNA-d/protamine and DNA-s/protamine coatings produced more roughened and hydrophilic surfaces than untreated Ti. Animal experiments showed that higher bone-to-implant ratios were achieved 3 and 6 weeks after implantation using DNA-d/protamine and DNA-s/protamine coatings compared with Ti. QCM measurements revealed that each coating contributed to significant earlier apatite formation in SBF. We conclude that both DNA-d/protamine and DNA-s/protamine coatings enhanced early bone formation. We suggest that a DNA-multilayer coating is useful for the surface modification of a Ti implant.
Topics: Animals; Coated Materials, Biocompatible; DNA; DNA, Single-Stranded; Dental Implants; Microscopy, Electron, Scanning; Prostheses and Implants; Rats; Surface Properties; Titanium
PubMed: 30009177
DOI: 10.1155/2018/9204391