scholarly journals A Review of Recent Developments in the Molecular Mechanisms of Bone Healing

2021 ◽  
Vol 22 (2) ◽  
pp. 767
Author(s):  
Emerito Carlos Rodríguez-Merchán
Keyword(s):  
Bone Healing ◽  
Estrogen Receptor Alpha ◽  
Molecular Mechanisms ◽  
Human Mesenchymal Stem Cells ◽  
Iliac Crest Bone Graft ◽  
Stem And Progenitor Cells ◽  
Recent Developments ◽  
Bone Morphogenetic Protein 9 ◽  
Fracture Consolidation ◽  
Orange Trees

Between 5 and 10 percent of fractures do not heal, a condition known as nonunion. In clinical practice, stable fracture fixation associated with autologous iliac crest bone graft placement is the gold standard for treatment. However, some recalcitrant nonunions do not resolve satisfactorily with this technique. For these cases, biological alternatives are sought based on the molecular mechanisms of bone healing, whose most recent findings are reviewed in this article. The pro-osteogenic efficacy of morin (a pale yellow crystalline flavonoid pigment found in old fustic and osage orange trees) has recently been reported, and the combined use of bone morphogenetic protein-9 (BMP9) and leptin might improve fracture healing. Inhibition with methyl-piperidino-pyrazole of estrogen receptor alpha signaling delays bone regeneration. Smoking causes a chondrogenic disorder, aberrant activity of the skeleton’s stem and progenitor cells, and an intense initial inflammatory response. Smoking cessation 4 weeks before surgery is therefore highly recommended. The delay in fracture consolidation in diabetic animals is related to BMP6 deficiency (35 kDa). The combination of bioceramics and expanded autologous human mesenchymal stem cells from bone marrow is a new and encouraging alternative for treating recalcitrant nonunions.

How do histone modifications contribute to transgenerational epigenetic inheritance in C. elegans?

2020 ◽  
Vol 48 (3) ◽  
pp. 1019-1034 ◽  
Author(s):  
Rachel M. Woodhouse ◽  
Alyson Ashe
Keyword(s):  
Histone Modifications ◽  
Molecular Mechanisms ◽  
Epigenetic Inheritance ◽  
Nematode Caenorhabditis Elegans ◽  
Histone Methyltransferases ◽  
Transgenerational Epigenetic Inheritance ◽  
C Elegans ◽  
Recent Developments ◽  
Gene Regulatory

Gene regulatory information can be inherited between generations in a phenomenon termed transgenerational epigenetic inheritance (TEI). While examples of TEI in many animals accumulate, the nematode Caenorhabditis elegans has proven particularly useful in investigating the underlying molecular mechanisms of this phenomenon. In C. elegans and other animals, the modification of histone proteins has emerged as a potential carrier and effector of transgenerational epigenetic information. In this review, we explore the contribution of histone modifications to TEI in C. elegans. We describe the role of repressive histone marks, histone methyltransferases, and associated chromatin factors in heritable gene silencing, and discuss recent developments and unanswered questions in how these factors integrate with other known TEI mechanisms. We also review the transgenerational effects of the manipulation of histone modifications on germline health and longevity.

scholarly journals Myelopoiesis during Solid Cancers and Strategies for Immunotherapy

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 968
Author(s):  
Tyler J. Wildes ◽  
Bayli DiVita Dean ◽  
Catherine T. Flores
Keyword(s):  
Myeloid Cells ◽  
Hematopoietic Stem ◽  
Cell Therapies ◽  
Broad Array ◽  
Stem And Progenitor Cells ◽  
Recent Developments ◽  
Immature Myeloid Cells ◽  
Significant Discovery ◽  
The Relationship ◽  
Clinical Advances

Our understanding of the relationship between the immune system and cancers has undergone significant discovery recently. Immunotherapy with T cell therapies and checkpoint blockade has meaningfully changed the oncology landscape. While remarkable clinical advances in adaptive immunity are occurring, modulation of innate immunity has proven more difficult. The myeloid compartment, including macrophages, neutrophils, and dendritic cells, has a significant impact on the persistence or elimination of tumors. Myeloid cells, specifically in the tumor microenvironment, have direct contact with tumor tissue and coordinate with tumor-reactive T cells to either stimulate or antagonize cancer immunity. However, the myeloid compartment comprises a broad array of cells in various stages of development. In addition, hematopoietic stem and progenitor cells at various stages of myelopoiesis in distant sites undergo significant modulation by tumors. Understanding how tumors exert their influence on myeloid progenitors is critical to making clinically meaningful improvements in these pathways. Therefore, this review will cover recent developments in our understanding of how solid tumors modulate myelopoiesis to promote the formation of pro-tumor immature myeloid cells. Then, it will cover some of the potential avenues for capitalizing on these mechanisms to generate antitumor immunity.

scholarly journals Let-7f miRNA regulates SDF-1α- and hypoxia-promoted migration of mesenchymal stem cells and attenuates mammary tumor growth upon exosomal release

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Virginia Egea ◽  
Kai Kessenbrock ◽  
Devon Lawson ◽  
Alexander Bartelt ◽  
Christian Weber ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tumor Growth ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Human Mesenchymal Stem Cells ◽  
Target Cells ◽  
Autophagic Flux ◽  
Stromal Cell Derived Factor

AbstractBone marrow-derived human mesenchymal stem cells (hMSCs) are recruited to damaged or inflamed tissues where they contribute to tissue repair. This multi-step process involves chemokine-directed invasion of hMSCs and on-site release of factors that influence target cells or tumor tissues. However, the underlying molecular mechanisms are largely unclear. Previously, we described that microRNA let-7f controls hMSC differentiation. Here, we investigated the role of let-7f in chemotactic invasion and paracrine anti-tumor effects. Incubation with stromal cell-derived factor-1α (SDF-1α) or inflammatory cytokines upregulated let-7f expression in hMSCs. Transfection of hMSCs with let-7f mimics enhanced CXCR4-dependent invasion by augmentation of pericellular proteolysis and release of matrix metalloproteinase-9. Hypoxia-induced stabilization of the hypoxia-inducible factor 1 alpha in hMSCs promoted cell invasion via let-7f and activation of autophagy. Dependent on its endogenous level, let-7f facilitated hMSC motility and invasion through regulation of the autophagic flux in these cells. In addition, secreted let-7f encapsulated in exosomes was increased upon upregulation of endogenous let-7f by treatment of the cells with SDF-1α, hypoxia, or induction of autophagy. In recipient 4T1 tumor cells, hMSC-derived exosomal let-7f attenuated proliferation and invasion. Moreover, implantation of 3D spheroids composed of hMSCs and 4T1 cells into a breast cancer mouse model demonstrated that hMSCs overexpressing let-7f inhibited tumor growth in vivo. Our findings provide evidence that let-7f is pivotal in the regulation of hMSC invasion in response to inflammation and hypoxia, suggesting that exosomal let-7f exhibits paracrine anti-tumor effects.

scholarly journals The Prion-Like Spreading of Alpha-Synuclein in Parkinson’s Disease: Update on Models and Hypotheses

2021 ◽  
Vol 22 (15) ◽  
pp. 8338
Author(s):  
Asad Jan ◽  
Nádia Pereira Gonçalves ◽  
Christian Bjerggaard Vaegter ◽  
Poul Henning Jensen ◽  
Nelson Ferreira
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Alpha Synuclein ◽  
Experimental Models ◽  
Cellular Factors ◽  
Recent Developments ◽  
Novel Targets ◽  
Presynaptic Protein

The pathological aggregation of the presynaptic protein α-synuclein (α-syn) and propagation through synaptically coupled neuroanatomical tracts is increasingly thought to underlie the pathophysiological progression of Parkinson’s disease (PD) and related synucleinopathies. Although the precise molecular mechanisms responsible for the spreading of pathological α-syn accumulation in the CNS are not fully understood, growing evidence suggests that de novo α-syn misfolding and/or neuronal internalization of aggregated α-syn facilitates conformational templating of endogenous α-syn monomers in a mechanism reminiscent of prions. A refined understanding of the biochemical and cellular factors mediating the pathological neuron-to-neuron propagation of misfolded α-syn will potentially elucidate the etiology of PD and unravel novel targets for therapeutic intervention. Here, we discuss recent developments on the hypothesis regarding trans-synaptic propagation of α-syn pathology in the context of neuronal vulnerability and highlight the potential utility of novel experimental models of synucleinopathies.

New horizons in mitochondrial contact site research

2020 ◽  
Vol 401 (6-7) ◽  
pp. 793-809
Author(s):  
Naama Zung ◽  
Maya Schuldiner
Keyword(s):  
Endoplasmic Reticulum ◽  
Molecular Mechanisms ◽  
Contact Site ◽  
New Horizons ◽  
Contact Sites ◽  
Future Goals ◽  
Close Proximity ◽  
Recent Developments ◽  
Site Field ◽  
First Contact

AbstractContact sites, areas where two organelles are held in close proximity through the action of molecular tethers, enable non-vesicular communication between compartments. Mitochondria have been center stage in the contact site field since the discovery of the first contact between mitochondria and the endoplasmic reticulum (ER) over 60 years ago. However, only now, in the last decade, has there been a burst of discoveries regarding contact site biology in general and mitochondrial contacts specifically. The number and types of characterized contacts increased dramatically, new molecular mechanisms enabling contact formation were discovered, additional unexpected functions for contacts were shown, and their roles in cellular and organismal physiology were emphasized. Here, we focus on mitochondria as we highlight the most recent developments, future goals and unresolved questions in the field.

scholarly journals 0188 : Molecular mechanisms involved in the vascular protection induced by estrogen receptor alpha during hypertension in the mouse

2015 ◽  
Vol 7 (2) ◽  
pp. 187-188
Author(s):  
Emmanuel Guivarc’H ◽  
Anne-Laure Guihot ◽  
Julie Favre ◽  
Emilie Vessières ◽  
Jamal Wakim ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Estrogen Receptor Alpha ◽  
Molecular Mechanisms ◽  
Vascular Protection ◽  
Receptor Alpha

Age- and stage-specific regulation patterns in the hematopoietic stem cell hierarchy

Blood ◽  
2001 ◽  
Vol 98 (10) ◽  
pp. 2966-2972 ◽  
Author(s):  
Hartmut Geiger ◽  
Jarrod M. True ◽  
Gerald de Haan ◽  
Gary Van Zant
Keyword(s):  
Linkage Analysis ◽  
Molecular Mechanisms ◽  
Hematopoietic Stem ◽  
Cell Compartments ◽  
Quantitative Trait Linkage Analysis ◽  
Specific Manner ◽  
Stem And Progenitor Cells ◽  
Specific Regulation ◽  
Stem Cell Hierarchy

Abstract The molecular mechanisms that regulate self-renewal and differentiation of very primitive hematopoietic stem and progenitor cells in vivo are still poorly understood. Despite the clinical relevance, even less is known about the mechanisms that regulate these cells in old animals. In a forward genetic approach, using quantitative trait linkage analysis in the mouse BXD recombinant inbred set, this study identified loci that regulate the genetic variation in the size of primitive hematopoietic cell compartments of young and old C57BL6 and DBA/2 animals. Linked loci were confirmed through the generation and analysis of congenic animals. In addition, a comparative linkage analysis revealed that the number of primitive hematopoietic cells and hematopoietic stem cells are regulated in a stage-specific and an age-specific manner.

(deleted)

2021 ◽  
Author(s):  
MV Osikov ◽  
EV Davydova ◽  
KS Abramov
Keyword(s):  
Bone Healing ◽  
Standard Therapy ◽  
Type I Collagen ◽  
Femoral Shaft ◽  
Control Group ◽  
Blood Levels ◽  
Type I ◽  
Mineral Density ◽  
Fracture Consolidation ◽  
To Receive

Efferent physical therapy holds promise as an adjunct to the combination treatment of femoral fractures in young, working-age individuals. The aim of the study was to investigate the dynamics of bone turnover markers at different stages of femoral fracture consolidation in patients undergoing ozone therapy. The study enrolled 20 men (group 2, 47.8 ± 3.5 years) with a femoral shaft fracture (AO/ASIF 32А, 32В). The control group (group 1, 46.8 ± 3.7 years) comprised 10 healthy males. Subgroup 2a (n = 10) was assigned to receive standard therapy; subgroup 2b (n = 10) was assigned to receive standard therapy complemented by minor autohemotherapy (MAHT) at 20 mg/L ozone concentrations. On days 7, 30 and 90, fracture consolidation was assessed on the RUST scale and blood levels of С-terminal telopeptides of type I collagen (bCTx, pg/ml) and procollagen type I carboxy-terminal propeptide (PICP, ng/ml) were measured. On day 7, the total RUST score in subgroups 2a and 2b was 4 points; on day 30, it was 6.5 and 8.7 points, respectively, and on day 90, it reached 10 and 11.5 points, respectively. Bone mineral density was as high as 90% in the MAHT subgroup vs. 78% in subgroup 2а, indicating faster bone healing. On day 30, bCTx levels in subgroup 2b were higher than in subgroup 2a (2289.4 [2145.3; 2365.4] vs. 1894.6 [1745.3; 2098.2], respectively. On day 7, PICP was significantly elevated in subgroup 2b in comparison with subgroup 2a; its levels peaked on days 30 and 90 (day 30: 268.3 [231.2; 286.3] vs. 183.2 [174.6; 195.6]; day 90: 584.6 [512.3; 589.3] vs. 351.2 [312.3; 369.4]. Thus, MAHT produces a positive effect on the quality and intensity of bone healing in men with isolated closed femoral shaft fractures.

scholarly journals Proopiomelanocortin, a polypeptide precursor with multiple functions: from physiology to pathological conditions

2003 ◽  
Vol 149 (2) ◽  
pp. 79-90 ◽  
Author(s):  
ML Raffin-Sanson ◽  
Y de Keyzer ◽  
X Bertagna
Keyword(s):  
Anterior Pituitary ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Single Gene ◽  
Local Production ◽  
Biological Functions ◽  
Multiple Functions ◽  
Pathological Conditions ◽  
Recent Developments ◽  
The Brain

Proopiomelanocortin (POMC) is the polypeptide precursor of ACTH. First discovered in anterior pituitary corticotroph cells, it has more recently been revealed to have many other physiological aspects. The fine molecular mechanisms of ACTH biosynthesis show that ACTH is but one piece of a puzzle which contains many other peptides. Present in various tIssues, among which are pituitary, hypothalamus, central nervous system and skin, POMC undergoes extensive post-translational processing. This processing is tIssue-specific and generates, depending on the case, various sets of peptides involved in completely diverse biological functions. POMC expressed in corticotroph cells of the pituitary is necessary for adrenal function. Recent developments have shown that POMC-expressing neurons in the brain play a major role in the control of pain and energy homeostasis. Local production of POMC-derived peptides in skin may influence melanogenesis. A still unknown function in the placenta is likely.POMC has become a paradigmatic polypeptide precursor model illustrating the variable roles of a single gene and its various products in different localities.

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