Stems Cells and the Pathways to Aging and Cancer

CD133 peptide-conjugated pyropheophorbide-a as a novel photosensitizer for targeted photodynamic therapy in colorectal cancer stem cells

Colorectal cancer (CRC) is the third most common cancer around the world. Recent findings suggest that cancer stem cells (CSCs) play a pivotal role in the resistance to current therapeutic modalities, including surgery and chemotherapy. Photodynamic therapy (PDT) is a promising non-invasive therapeutic strategy for advanced metastatic CRC. Traditional photosensitizers such as pyropheophorbide-a (Pyro) lack tumor selectivity, causing unwanted treatment-related toxicity to the surrounding normal tissue. In order to enhance the targeting properties of Pyro, we synthesize a novel photosensitizer, CD133-Pyro, via the conjugation of Pyro to a peptide domain targeting CD133, which is highly expressed on CRC CSCs and correlated with poor prognosis of CRC patients. We demonstrate that CD133-Pyro possesses the targeted delivery capacity both in CRC CSCs derived from HT29 and SW620 cell lines and in a xenograft mouse model of tumor growth. CD133-Pyro PDT can promote the production of reactive oxygen species (ROS), suppress the stemness properties, and induce autophagic cell death in CRC CSCs. Furthermore, CD133-Pyro PDT has a potent inhibitory effect on CRC CSC-derived xenograft tumors in nude mice. These findings may offer a useful and important strategy for the treatment of CRC through targeting CSCs.

Cobalt Phosphide (Co2P) with Notable Electrocatalytic Activity Designed for Sensitive and Selective Enzymeless Bioanalysis of Hydrogen Peroxide

In this work, cobalt phosphide nanoparticles (Co₂P NPs) were prepared by simple and mild hydrothermal method without the use of harmful phosphorous source. The morphological structure and surface component of Co₂P were characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy measurements. Considering the excellent electrocatalytic reduction activity and good electrical conductivity of transition-metal phosphide, we fabricated Co₂P NPs on indium tin oxide (ITO) substrate (Co₂P/ITO) for H₂O₂ detection. The Co₂P/ITO transducer displayed a rapid amperometric response less than 5 s, a broader response range from 0.001 to 10.0 mM and a low detection limit of 0.65 μM. In addition, the non-enzymatic Co₂P/ITO sensor showed outstanding selectivity, reproducibility, repeatability and stability, all of which qualified the Co₂P/ITO electrode for quite a reliable and promising biosensor for H₂O₂ sensing.

Protection of hematopoietic stem cells from stress-induced exhaustion and aging

PURPOSE OF REVIEW

Hematopoietic stem cells (HSCs) are defined by their ability to self-renew and differentiate to replenish all blood lineages throughout adult life. Under homeostasis, the majority of HSCs are quiescent, and few stem cells are cycling to sustain hematopoiesis. However, HSCs can be induced to proliferate and differentiate in response to stress signals produced during infection, inflammation, chemotherapy, radiation, bone marrow transplantation, and aging. Recent evidence suggests that acute and chronic stress impact the number and function of HSCs including their ability to repopulate and produce mature cells. This review will focus on how chronic stress affects HSC biology and methods to mitigate HSC loss during chronic hematopoietic stress.

RECENT FINDINGS

Quiescent HSCs exit dormancy, divide, and differentiate to maintain steady-state hematopoiesis. Under conditions of acute stress including infection or blood loss some HSCs are pushed into division by cytokines and proinflammatory stimuli to differentiate and provide needed myeloid and erythroid cells to protect and reconstitute the host; after which, hematopoiesis returns to steady-state with minimal loss of HSC function. However, under conditions of chronic stress including serial bone marrow transplantation (BMT), chronic inflammation, and genotoxic stress (chemotherapy) and aging, HSCs are continuously induced to proliferate and undergo accelerated exhaustion. Recent evidence demonstrates that ablation of inhibitor of DNA binding 1 (Id1) gene can protect HSCs from exhaustion during chronic proliferative stress by promoting HSC quiescence.

SUMMARY

Increasing our understanding of the molecular processes that protect HSCs from chronic proliferative stress could lead to therapeutic opportunities to prevent accelerated HSC exhaustion during physiological stress, genotoxic stress, BMT, and aging.

Versatile quantitative biopsy: an approach for cost-effective detection of hydrogen peroxide in tissue specimens

In the presence of H₂O₂, the amylose released by the micelles is converted into glucose by glucoamylase and detected by a PGM.

Fate of Hematopoiesis During Aging. What Do We Really Know, and What are its Implications?

There is an ongoing shift in demographics such that older persons will outnumber young persons in the coming years, and with it age-associated tissue attrition and increased diseases and disorders. There has been increased information on the association of the aging process with dysregulation of hematopoietic stem (HSC) and progenitor (HPC) cells, and hematopoiesis. This review provides an extensive up-to date summary on the literature of aged hematopoiesis and HSCs placed in context of potential artifacts of the collection and processing procedure, that may not be totally representative of the status of HSCs in their in vivo bone marrow microenvironment, and what the implications of this are for understanding aged hematopoiesis. This review covers a number of interactive areas, many of which have not been adequately explored. There are still many unknowns and mechanistic insights to be elucidated to better understand effects of aging on the hematopoietic system, efforts that will take multidisciplinary approaches, and that could lead to means to ameliorate at least some of the dysregulation of HSCs and HPCs associated with the aging process. Graphical Abstract.

Proteomic analysis of young and old mouse hematopoietic stem cells and their progenitors reveals post-transcriptional regulation in stem cells

The balance of hematopoietic stem cell (HSC) self-renewal and differentiation is critical for a healthy blood supply; imbalances underlie hematological diseases. The importance of HSCs and their progenitors have led to their extensive characterization at genomic and transcriptomic levels. However, the proteomics of hematopoiesis remains incompletely understood. Here we report a proteomics resource from mass spectrometry of mouse young adult and old adult mouse HSCs, multipotent progenitors and oligopotent progenitors; 12 cell types in total. We validated differential protein levels, including confirmation that Dnmt3a protein levels are undetected in young adult mouse HSCs until forced into cycle. Additionally, through integrating proteomics and RNA-sequencing datasets, we identified a subset of genes with apparent post-transcriptional repression in young adult mouse HSCs. In summary, we report proteomic coverage of young and old mouse HSCs and progenitors, with broader implications for understanding mechanisms for stem cell maintenance, niche interactions and fate determination.

Age-related loss of gene-to-gene transcriptional coordination among single cells

A long-standing model holds that stochastic aberrations of transcriptional regulation play a key role in the process of ageing. While transcriptional dysregulation is observed in many cell types in the form of increased cell-to-cell variability, its generality to all cell types remains doubted. Here, we propose a new approach for analysing transcriptional regulation in single-cell RNA sequencing data by focusing on the global coordination between the genes rather than the variability of individual genes or correlations between pairs of genes. Consistently, across very different organisms and cell types, we find a decrease in the gene-to-gene transcriptional coordination in ageing cells. In addition, we find that loss of gene-to-gene transcriptional coordination is associated with high mutational load of a specific, age-related signature and with radiation-induced DNA damage. These observations suggest a general, potentially universal, stochastic attribute of transcriptional dysregulation in ageing.

Switching of vascular cells towards atherogenesis, and other factors contributing to atherosclerosis: a systematic review

Background

Onset, development and progression of atherosclerosis are complex multistep processes. Many aspects of atherogenesis are not yet properly known. This study investigates the changes in vasculature that contribute to switching of vascular cells towards atherogenesis, focusing mainly on ageing.

Methods

Databases including PubMed, MEDLINE and Google Scholar were searched for published articles without any date restrictions, involving atherogenesis, vascular homeostasis, aging, gene expression, signaling pathways, angiogenesis, vascular development, vascular cell differentiation and maintenance, vascular stem cells, endothelial and vascular smooth muscle cells.

Results

Atherogenesis is a complex multistep process that unfolds in a sequence. It is caused by alterations in: epigenetics and genetics, signaling pathways, cell circuitry, genome stability, heterotypic interactions between multiple cell types and pathologic alterations in vascular microenvironment. Such alterations involve pathological changes in: Shh, Wnt, NOTCH signaling pathways, TGF beta, VEGF, FGF, IGF 1, HGF, AKT/PI3K/ mTOR pathways, EGF, FOXO, CREB, PTEN, several apoptotic pathways, ET - 1, NF-κB, TNF alpha, angiopoietin, EGFR, Bcl - 2, NGF, BDNF, neurotrophins, growth factors, several signaling proteins, MAPK, IFN, TFs, NOs, serum cholesterol, LDL, ephrin, its receptor pathway, HoxA5, Klf3, Klf4, BMPs, TGFs and others.This disruption in vascular homeostasis at cellular, genetic and epigenetic level is involved in switching of the vascular cells towards atherogenesis. All these factors working in pathologic manner, contribute to the development and progression of atherosclerosis.

Conclusion

The development of atherosclerosis involves the switching of gene expression towards pro-atherogenic genes. This happens because of pathologic alterations in vascular homeostasis. When pathologic alterations in epigenetics, genetics, regulatory genes, microenvironment and vascular cell biology accumulate beyond a specific threshold, then the disease begins to express itself phenotypically. The process of biological ageing is one of the most significant factors in this aspect as it is also involved in the decline in homeostasis, maintenance and integrity.The process of atherogenesis unfolds sequentially (step by step) in an interconnected loop of pathologic changes in vascular biology. Such changes are involved in 'switching' of vascular cells towards atherosclerosis.

Treating Senescence like Cancer: Novel Perspectives in Senotherapy of Chronic Diseases

The WHO estimated around 41 million deaths worldwide each year for age-related non-communicable chronic diseases. Hence, developing strategies to control the accumulation of cell senescence in living organisms and the overall aging process is an urgently needed problem of social relevance. During aging, many biological processes are altered, which globally induce the dysfunction of the whole organism. Cell senescence is one of the causes of this modification. Nowadays, several drugs approved for anticancer therapy have been repurposed to treat senescence, and others are under scrutiny in vitro and in vivo to establish their senomorphic or senolytic properties. In some cases, this research led to a significant increase in cell survival or to a prolonged lifespan in animal models, at least. Senomorphics can act to interfere with a specific pathway in order to restore the appropriate cellular function, preserve viability, and to prolong the lifespan. On the other hand, senolytics induce apoptosis in senescent cells allowing the remaining non–senescent population to preserve or restore tissue function. A large number of research articles and reviews recently addressed this topic. Herein, we would like to focus attention on those chemical agents with senomorphic or senolytic properties that perspectively, according to literature, suggest a potential application as senotherapeutics for chronic diseases.

Recent advances in ultrathin two-dimensional materials and biomedical applications for reactive oxygen species generation and scavenging

Graphene and graphene-like two-dimensional (2D) nanomaterials, such as black phosphorus (BP), transition metal carbides/carbonitrides (MXene) and transition metal dichalcogenides (TMD), have been extensively studied in recent years due to their unique physical and chemical properties. With atomic-scale thickness, these 2D materials and their derivatives can react with ROS and even scavenge ROS in the dark. With excellent biocompatibility and biosafety, they show great application potential in the antioxidant field and ROS detection for diagnosis. They can also generate ROS under light and be applied in antibacterial, photodynamic therapy (PDT), and other biomedical fields. Understanding the degradation mechanism of 2D nanomaterials by ROS generated under ambient conditions is crucial to developing air stable devices and expanding their application ranges. In this review, we summarize recent advances in 2D materials with a focus on the relationship between their intrinsic structure and the ROS scavenging or generating ability. We have also highlighted important guidelines for the design and synthesis of highly efficient ROS scavenging or generating 2D materials along with their biomedical applications.

Sestrin family - the stem controlling healthy ageing

Sestrins are a family of stress-responsive antioxidant proteins responsible for regulation of cell viability and metabolism. The best known Sestrin targets are mTORC1 and mTORC2 kinases that control different cellular processes including growth, viability, autophagy, and mitochondrial metabolism. Inactivation of the single Sestrin gene in invertebrates has an adverse impact on their healthspan and longevity, whereas each of the three Sestrin genes in mammals and other vertebrate organisms has a different impact on maintenance of a particular tissue, affecting its stress tolerance, function and regenerative capability. As a result, Sestrins attenuate ageing and suppress development of many age-related diseases including myocardial infarction, muscle atrophy, diabetes, and immune dysfunction, but exacerbate development of chronic obstructive pulmonary disease. Moreover, Sestrins play opposite roles in carcinogenesis in different tissues. Stem cells support tissue remodelling that influences ageing, and Sestrins might suppress ageing and age-related pathologies through control of stem cell biology. In this review, we will discuss the potential link between Sestrins, stem cells, and ageing.

Steroid 5α-Reductase Type I Induces Cell Viability and Migration via Nuclear Factor-κB/Vascular Endothelial Growth Factor Signaling Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Steroid 5α-reductase type I (SRD5A1), as an important part of the steroid metabolism, converts testosterone to dihydrotestosterone and regulates sex hormone levels, which accommodates tumor occurrence or development. However, the underlying molecular mechanism of SRD5A1 in CRC remains unclear. We compared SRD5A1 expression in CRC tissues with normal controls by immunohistochemistry and found that elevated SRD5A1 in CRC was relevant for poor patient prognosis. Furthermore, inducible downregulation of SRD5A1 by small hairpin RNA reduced cell viability, promoted cell cycle arrest, and induced cell apoptosis and cellular senescence of CRC cells, as well as attenuated cell migration ability. In the following experiments, we used dutasteride (an inhibitor of SRD5A1/2) to explore its inhibitory effect on the biological processes of CRC cells, as mentioned earlier. Further mechanism study demonstrated that the repression of SRD5A1 abolished the expression of p65 and vascular endothelial growth factor, suggesting that SRD5A1 might regulate cell viability and migration through nuclear factor-κB/vascular endothelial growth factor signaling pathway. Collectively, these findings implicate SRD5A1 acting as a novel biomarker for CRC diagnosis and prognosis and provide compelling evidence for the future evaluation of dutasteride as a promising candidate for CRC treatment.

Cellular and Molecular Mechanisms of Environmental Pollutants on Hematopoiesis

Hematopoiesis is a complex and intricate process that aims to replenish blood components in a constant fashion. It is orchestrated mostly by hematopoietic progenitor cells (hematopoietic stem cells (HSCs)) that are capable of self-renewal and differentiation. These cells can originate other cell subtypes that are responsible for maintaining vital functions, mediate innate and adaptive immune responses, provide tissues with oxygen, and control coagulation. Hematopoiesis in adults takes place in the bone marrow, which is endowed with an extensive vasculature conferring an intense flow of cells. A myriad of cell subtypes can be found in the bone marrow at different levels of activation, being also under constant action of an extensive amount of diverse chemical mediators and enzymatic systems. Bone marrow platelets, mature erythrocytes and leukocytes are delivered into the bloodstream readily available to meet body demands. Leukocytes circulate and reach different tissues, returning or not returning to the bloodstream. Senescent leukocytes, specially granulocytes, return to the bone marrow to be phagocytized by macrophages, restarting granulopoiesis. The constant high production and delivery of cells into the bloodstream, alongside the fact that blood cells can also circulate between tissues, makes the hematopoietic system a prime target for toxic agents to act upon, making the understanding of the bone marrow microenvironment vital for both toxicological sciences and risk assessment. Environmental and occupational pollutants, therapeutic molecules, drugs of abuse, and even nutritional status can directly affect progenitor cells at their differentiation and maturation stages, altering behavior and function of blood compounds and resulting in impaired immune responses, anemias, leukemias, and blood coagulation disturbances. This review aims to describe the most recently investigated molecular and cellular toxicity mechanisms of current major environmental pollutants on hematopoiesis in the bone marrow.

Tsc1 Regulates the Proliferation Capacity of Bone-Marrow Derived Mesenchymal Stem Cells

TSC1 is a tumor suppressor that inhibits cell growth via negative regulation of the mammalian target of rapamycin complex (mTORC1). TSC1 mutations are associated with Tuberous Sclerosis Complex (TSC), characterized by multiple benign tumors of mesenchymal and epithelial origin. TSC1 modulates self-renewal and differentiation in hematopoietic stem cells; however, its effects on mesenchymal stem cells (MSCs) are unknown. We investigated the impact of Tsc1 inactivation in murine bone marrow (BM)-MSCs, using tissue-specific, transgelin (Tagln)-mediated cre-recombination, targeting both BM-MSCs and smooth muscle cells. Tsc1 mutants were viable, but homozygous inactivation led to a dwarfed appearance with TSC-like pathologies in multiple organs and reduced survival. In young (28 day old) mice, Tsc1 deficiency-induced significant cell expansion of non-hematopoietic BM in vivo, and MSC colony-forming potential in vitro, that was normalized upon treatment with the mTOR inhibitor, everolimus. The hyperproliferative BM-MSC phenotype was lost in aged (1.5 yr) mice, and Tsc1 inactivation was also accompanied by elevated ROS and increased senescence. ShRNA-mediated knockdown of Tsc1 in BM-MSCs replicated the hyperproliferative BM-MSC phenotype and led to impaired adipogenic and myogenic differentiation. Our data show that Tsc1 is a negative regulator of BM-MSC proliferation and support a pivotal role for the Tsc1-mTOR axis in the maintenance of the mesenchymal progenitor pool.

Stabilization of telomere by the antioxidant property of polyphenols: Anti-aging potential

Aging is a form of a gradual loss of physiological integrity that results in impaired cellular function and ultimately increased vulnerability to disease and death. This process is a significant risk factor for critical age-related disorders such as cancer, diabetes, cardiovascular disease, and neurological conditions. Several mechanisms contribute to aging, most notably progressive telomeres shortening, which can be counteracted by telomerase enzyme activity and increasing in this enzyme activity associated with partly delaying the onset of aging. Individual behaviors and environmental factors such as nutrition affect the life-span by impact the telomerase activity rate. Healthy eating habits, including antioxidant intakes, such as polyphenols, can have a positive effect on telomere length by this mechanism. In this review, after studying the underlying mechanisms of aging and understanding the relationships between telomeres, telomerase, and aging, it has been attempted to explain the effect of polyphenols on reversing the oxidative stress and aging process.

Muscarinic acetylcholine receptor regulates self-renewal of early erythroid progenitors

Adult stem and progenitor cells are uniquely capable of self-renewal, and targeting this process represents a potential therapeutic opportunity. The early erythroid progenitor, burst-forming unit erythroid (BFU-E), has substantial self-renewal potential and serves as a key cell type for the treatment of anemias. However, our understanding of mechanisms underlying BFU-E self-renewal is extremely limited. Here, we found that the muscarinic acetylcholine receptor, cholinergic receptor, muscarinic 4 (CHRM4), pathway regulates BFU-E self-renewal and that pharmacological inhibition of CHRM4 corrects anemias of myelodysplastic syndrome (MDS), aging, and hemolysis. Genetic down-regulation of CHRM4 or pharmacologic inhibition of CHRM4 using the selective antagonist PD102807 promoted BFU-E self-renewal, whereas deletion of Chrm4 increased erythroid cell production under stress conditions in vivo. Moreover, muscarinic acetylcholine receptor antagonists corrected anemias in mouse models of MDS, aging, and hemolysis in vivo, extending the survival of mice with MDS relative to that of controls. The effects of muscarinic receptor antagonism on promoting expansion of BFU-Es were mediated by cyclic AMP induction of the transcription factor CREB, whose targets up-regulated key regulators of BFU-E self-renewal. On the basis of these data, we propose a model of hematopoietic progenitor self-renewal through a cholinergic-mediated "hematopoietic reflex" and identify muscarinic acetylcholine receptor antagonists as potential therapies for anemias associated with MDS, aging, and hemolysis.

The oncogenic potential of a mutant TP53 gene explored in two spontaneous lung cancer mice models

Background

Lung cancer is the number one cancer killer worldwide. A major drawback in the lung cancer treatment field is the lack of realistic mouse models that replicate the complexity of human malignancy and immune contexture within the tumor microenvironment. Such models are urgently needed. Mutations of the tumor protein p53 are among the most common alterations in human lung cancers.

Methods

Previously, we developed a line of lung cancer mouse model where mutant human TP53-273H is expressed in a lung specific manner in FVB/N background. To investigate whether the human TP53 mutant has a similar oncogenic potential when it is expressed in another strain of mouse, we crossed the FVB/N-SPC-TP53-273H mice to A/J strain and created A/J-SPC-TP53-273H transgenic mice. We then compared lung tumor formation between A/J-SPC-TP53-273H and FVB/N-SPC-TP53-273H.

Results

We found the TP53-273H mutant gene has a similar oncogenic potential in lung tumor formation in both mice strains, although A/J strain mice have been found to be a highly susceptible strain in terms of carcinogen-induced lung cancer. Both transgenic lines survived more than 18 months and developed age related lung adenocarcinomas. With micro CT imaging, we found the FVB-SPC-TP53-273H mice survived more than 8 weeks after initial detection of lung cancer, providing a sufficient window for evaluating new anti-cancer agents.

Conclusions

Oncogenic potential of the most common genetic mutation, TP53-273H, in human lung cancer is unique when it is expressed in different strains of mice. Our mouse models are useful tools for testing novel immune checkpoint inhibitors or other therapeutic strategies in the treatment of lung cancer.

Wnt-induced, TRP53-mediated Cell Cycle Arrest of Precursors Underlies Interstitial Cell of Cajal Depletion During Aging

BACKGROUND & AIMS

Gastric dysfunction in the elderly may cause reduced food intake, frailty, and increased mortality. The pacemaker and neuromodulator cells interstitial cells of Cajal (ICC) decline with age in humans, and their loss contributes to gastric dysfunction in progeric klotho mice hypomorphic for the anti-aging Klotho protein. The mechanisms of ICC depletion remain unclear. Klotho attenuates Wnt (wingless-type MMTV integration site) signaling. Here, we examined whether unopposed Wnt signaling could underlie aging-associated ICC loss by up-regulating transformation related protein TRP53 in ICC stem cells (ICC-SC).

METHODS

Mice aged 1-107 weeks, klotho mice, APC^Δ468 mice with overactive Wnt signaling, mouse ICC-SC, and human gastric smooth muscles were studied by RNA sequencing, reverse transcription-polymerase chain reaction, immunoblots, immunofluorescence, histochemistry, flow cytometry, and methyltetrazolium, ethynyl/bromodeoxyuridine incorporation, and ex-vivo gastric compliance assays. Cells were manipulated pharmacologically and by gene overexpression and RNA interference.

RESULTS

The klotho and aged mice showed similar ICC loss and impaired gastric compliance. ICC-SC decline preceded ICC depletion. Canonical Wnt signaling and TRP53 increased in gastric muscles of klotho and aged mice and middle-aged humans. Overstimulated canonical Wnt signaling increased DNA damage response and TRP53 and reduced ICC-SC self-renewal and gastric ICC. TRP53 induction persistently inhibited G₁/S and G₂/M cell cycle phase transitions without activating apoptosis, autophagy, cellular quiescence, or canonical markers/mediators of senescence. G₁/S block reflected increased cyclin-dependent kinase inhibitor 1B and reduced cyclin D1 from reduced extracellular signal-regulated kinase activity.

CONCLUSIONS

Increased Wnt signaling causes age-related ICC loss by up-regulating TRP53, which induces persistent ICC-SC cell cycle arrest without up-regulating canonical senescence markers.

Mutation accumulation and developmental lineages in normal and Down syndrome human fetal haematopoiesis

Children show a higher incidence of leukemia compared to young adolescents, yet their cells have less age-related (oncogenic) somatic mutations. Newborns with Down syndrome have an even higher risk of developing leukemia, which is thought to be driven by mutations that accumulate during fetal development. To characterize mutation accumulation in individual stem and progenitor cells of Down syndrome and karyotypically normal fetuses, we clonally expanded single cells and performed whole-genome sequencing. We found a higher mutation rate in haematopoietic stem and progenitor cells during fetal development compared to the post-infant rate. In fetal trisomy 21 cells the number of somatic mutations is even further increased, which was already apparent during the first cell divisions of embryogenesis before gastrulation. The number and types of mutations in fetal trisomy 21 haematopoietic stem and progenitor cells were similar to those in Down syndrome-associated myeloid preleukemia and could be attributed to mutational processes that were active during normal fetal haematopoiesis. Finally, we found that the contribution of early embryonic cells to human fetal tissues can vary considerably between individuals. The increased mutation rates found in this study, may contribute to the increased risk of leukemia early during life and the higher incidence of leukemia in Down syndrome.

Recent advances in chronic lymphocytic leukemia therapy

Chronic lymphocytic leukemia is a genetically heterogeneous disease, and a complex set of genetic alterations is associated with its pathogenesis. CLL is the most common leukemia in the western countries, whereas it is rare in Asia, including Korea. The prognostic models integrate the traditional staging systems developed by Rai et al. and Binet et al. with biochemical and genetic markers. With the advent of molecular biology, a variety of targeted agents, including anti-CD20 antibodies, inhibitors of BCR signaling pathway, and BCL-2 inhibitors, have been introduced, which has changed the landscape of CLL treatment greatly. This review will focus on the risk stratification and the management of CLL in the era of novel small molecules.

Per2 Upregulation in Circulating Hematopoietic Progenitor Cells During Chronic HIV Infection

Chronic HIV infection accelerates immune aging and is associated with abnormal hemato-lymphopoiesis, but the relationship between HIV-induced aging and Hematopoietic Progenitor Cells (HPC) function is not well-defined. In the context of aging, it has been demonstrated using a murine model that Per2 (Period circadian clock 2) is a negative regulator of HPC survival and lineage potential. A possible involvement of Per2 modulation on hematopoietic failure during HIV infection has not yet been investigated. The aim of this study was to analyze whether Per2 is differently expressed and regulated on HPC during HIV infection, possibly providing a therapeutic target to restore lymphoid potential in the HPC compartment. To this purpose, Per2 expression in circulating HPC was compared in 69 chronic HIV infected patients under successful ART and in matched 30 uninfected healthy donors (HD). HPC aging was assessed by measuring relative telomere length (RTL), and HPC functionality was evaluated by Colony Forming Cell (CFC) assay from both ex vivo HIV+ patients and in vitro Per2 overexpressing donors. Our results showed a lower RTL in HPC and a decrease of white progenitor colonies from HIV+ patients with lower CD4 respect to those with higher CD4 T cell count (<500 respect to >500 CD4 T cell/mmc). Interestingly, we found that the frequency of Per2-expressing HPC is higher in HIV+ patients than in HD and correlated to RTL of CFC derived cells, highlighting a relationship between low proliferative rate and Per2 expression. Indeed, the in vitro overexpression of Per2 resulted in a significant decrease of white progenitor colonies respect to control cells. Finally, we showed that the deacetylase Sirtuin 1, a negative regulator of Per2, was downregulated in HPC from HIV+ patients, and the peripheral blood treatment with resveratrol (Sirtuin 1 inducer) determined a decrease of Per2 expressing HPC. Altogether, these results suggest that during HIV infection, Per2 is involved in the regulation of HPC expansion and differentiation and its overexpression may impair the immune reconstitution. These data support the rationale to explore the role of this regulatory mechanism during aged-associated hemato-lymphopoiesis impairment in HIV infection.

The Ban on US Government Funding Research Using Human Fetal Tissues: How Does This Fit with the NIH Mission to Advance Medical Science for the Benefit of the Citizenry?

Some have argued that human fetal tissue research is unnecessary and/or immoral. Recently, the Trump administration has taken the drastic––and we believe misguided––step to effectively ban government-funded research on fetal tissue altogether. In this article, we show that entire lines of research and their clinical outcomes would not have progressed had fetal tissue been unavailable. We argue that this research has been carried out in a manner that is ethical and legal, and that it has provided knowledge that has saved lives, particularly those of pregnant women, their unborn fetuses, and newborns. We believe that those who support a ban on the use of fetal tissue are halting medical progress and therefore endangering the health and lives of many, and for this they should accept responsibility. At the very least, we challenge them to be true to their beliefs: if they wish to short-circuit a scientific process that has led to medical advances, they should pledge to not accept for themselves the health benefits that such advances provide.

Persistent DNA damage-induced NLRP12 improves hematopoietic stem cell function

NOD-like receptor 12 (NLRP12) is a member of the nucleotide-binding domain and leucine-rich repeat containing receptor inflammasome family that plays a central role in innate immunity. We previously showed that DNA damage upregulated NLRP12 in hematopoietic stem cells (HSCs) of mice deficient in the DNA repair gene Fanca. However, the role of NLRP12 in HSC maintenance is not known. Here, we show that persistent DNA damage-induced NLRP12 improves HSC function in both mouse and human models of DNA repair deficiency and aging. Specifically, treatment of Fanca-/- mice with the DNA cross-linker mitomycin C or ionizing radiation induces NLRP12 upregulation in phenotypic HSCs. NLRP12 expression is specifically induced by persistent DNA damage. Functionally, knockdown of NLRP12 exacerbates the repopulation defect of Fanca-/- HSCs. Persistent DNA damage-induced NLRP12 was also observed in the HSCs from aged mice, and depletion of NLRP12 in these aged HSCs compromised their self-renewal and hematopoietic recovery. Consistently, overexpression of NLRP12 substantially improved the long-term repopulating function of Fanca-/- and aged HSCs. Finally, persistent DNA damage-induced NLRP12 maintains the function of HSCs from patients with FA or aged donors. These results reveal a potentially novel role of NLRP12 in HSC maintenance and suggest that NLRP12 targeting has therapeutic potential in DNA repair disorders and aging.

The mitochondrial metabolic checkpoint in stem cell aging and rejuvenation

Stem cell aging contributes to aging-associated tissue degeneration and dysfunction. Recent studies reveal a mitochondrial metabolic checkpoint that regulates stem cell quiescence and maintenance, and dysregulation of the checkpoint leads to functional deterioration of aged stem cells. Here, we present the evidence supporting the mitochondrial metabolic checkpoint regulating stem cell aging and demonstrating the feasibility to target this checkpoint to reverse stem cell aging. We discuss the mechanisms by which mitochondrial stress leads to stem cell deterioration. We speculate the therapeutic potential of targeting the mitochondrial metabolic checkpoint for rejuvenating aged stem cells and improving aging tissue functions.

Muscle stem cell aging: identifying ways to induce tissue rejuvenation

Aging is characterized by the functional and regenerative decline of tissues and organs. This regenerative decline is a consequence of the numerical and functional loss of adult stem cells, which are the corner stone of tissue homeostasis and repair. A palpable example of this decline is provided by skeletal muscle, a specialized tissue composed of postmitotic myofibers that contract to generate force. Skeletal muscle stem cells (satellite cells) are long-lived and support muscle regeneration throughout life, but at advanced age they fail for largely undefined reasons. Here, we discuss recent advances in the understanding of how satellite cells integrate diverse intrinsic and extrinsic processes to ensure optimal homeostatic function and how this integration is perturbed during aging, causing regenerative failure. With this increased understanding, it is now feasible to design and test interventions that delay satellite cell aging. We discuss the exciting new therapeutic potential of integrating and combining distinct anti-aging strategies for regenerative medicine.

Iron overload inhibits self-renewal of human pluripotent stem cells via DNA damage and generation of reactive oxygen species

Iron overload affects the cell cycle of various cell types, but the effect of iron overload on human pluripotent stem cells has not yet been reported. Here, we show that the proliferation capacities of human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) were significantly inhibited by ferric ammonium citrate (FAC) in a concentration‐dependent manner. In addition, deferoxamine protected hESCs/hiPSCs against FAC‐induced cell‐cycle arrest. However, iron overload did not affect pluripotency in hESCs/hiPSCs. Further, treatment of hiPSCs with FAC resulted in excess reactive oxygen species production and DNA damage. Collectively, our findings provide new insights into the role of iron homeostasis in the maintenance of self‐renewal in human pluripotent stem cells.

Highly dispersive Pt-Pd nanoparticles on graphene oxide sheathed carbon fiber microelectrodes for electrochemical detection of H2O2 released from living cells

We report a facile strategy for the synthesis of surfactant-free, small and highly dispersive Pt-Pd nanoparticles on graphene oxide (Pt-Pd NPs/GO) by an electroless deposition method, which is sheathed on carbon fiber microelectrodes (CFMs) as an electrochemical sensing platform for highly sensitive and selective detection of hydrogen peroxide (H₂O₂) released from the living cells. GO serves as the reducing agent and stabilizer for electroless deposition of Pd NPs on the surface of GO owing to its low work function (4.38 eV) and highly conjugated electronic structure. The obtained Pd NPs/GO have a relatively high work function (4.64 eV), and thereby could be used as stabilizer for synthesis of surfactant-free, small and highly dispersive Pt-Pd NPs/GO by chemical reduction of K₂PtCl₄. The obtained Pt-Pd NPs have a uniform size of 4.0 ± 0.6 nm on the surface of GO. Moreover, the Pt-Pd NPs/GO sheathed CFMs exhibit an excellent electrocatalytic activity for the reduction of H₂O₂ with a low detection limit of 0.3 μM and good selectivity. These good properties enable the modified microelectrode to detect the H₂O₂ released from living cells.

AMPK Regulates Developmental Plasticity through an Endogenous Small RNA Pathway in Caenorhabditis elegans

Caenorhabditis elegans larvae can undergo developmental arrest upon entry into the dauer stage in response to suboptimal growth conditions. Dauer larvae can exit this stage in replete conditions with no reproductive consequence. During this diapause stage, the metabolic regulator AMP-activated protein kinase (AMPK) ensures that the germ line becomes quiescent to maintain germ cell integrity. Animals that lack all AMPK signalling undergo germline hyperplasia upon entering dauer, while those that recover from this stage become sterile. Neuronal AMPK expression in otherwise AMPK-deficient animals is sufficient for germline quiescence and germ cell integrity and its effects are likely mediated through an endogenous small RNA pathway. Upon impairing small RNA biosynthesis, the post-dauer fertility is restored in AMPK mutants. These data suggest that AMPK may function in neurons to relay a message through small RNAs to the germ cells to alter their quiescence in the dauer stage, thus challenging the permeability of the Weismann barrier.

Somatic selection of poorly differentiating variant stem cell clones could be a key to human ageing

Any replicating system in which heritable variants with differing replicative potentials can arise is subject to a Darwinian evolutionary process. The continually replicating adult tissue stem cells that control the integrity of many tissues of long-lived, multicellular, complex vertebrate organisms, including humans, constitute such a replicating system. Our suggestion is that somatic selection for mutations (or stable epigenetic changes) that cause an increased rate of adult tissue stem cell proliferation, and their long-term persistence, at the expense of normal differentiation, is a major key to the ageing process. Once an organism has passed the reproductive age, there is no longer any significant counterselection at the organismal level to this inevitable cellular level Darwinian process.

Mitochondrial Stress-Initiated Aberrant Activation of the NLRP3 Inflammasome Regulates the Functional Deterioration of Hematopoietic Stem Cell Aging

Aging-associated defects in hematopoietic stem cells (HSCs) can manifest in their progeny, leading to aberrant activation of the NLRP3 inflammasome in macrophages and affecting distant tissues and organismal health span. Whether the NLRP3 inflammasome is aberrantly activated in HSCs during physiological aging is unknown. We show here that SIRT2, a cytosolic NAD⁺-dependent deacetylase, is required for HSC maintenance and regenerative capacity at an old age by repressing the activation of the NLRP3 inflammasome in HSCs cell autonomously. With age, reduced SIRT2 expression and increased mitochondrial stress lead to aberrant activation of the NLRP3 inflammasome in HSCs. SIRT2 overexpression, NLRP3 inactivation, or caspase 1 inactivation improves the maintenance and regenerative capacity of aged HSCs. These results suggest that mitochondrial stress-initiated aberrant activation of the NLRP3 inflammasome is a reversible driver of the functional decline of HSC aging and highlight the importance of inflammatory signaling in regulating HSC aging.

The aging skin microenvironment dictates stem cell behavior

Aging manifests with architectural alteration and functional decline of multiple organs throughout an organism. In mammals, aged skin is accompanied by a marked reduction in hair cycling and appearance of bald patches, leading researchers to propose that hair follicle stem cells (HFSCs) are either lost, differentiate, or change to an epidermal fate during aging. Here, we employed single-cell RNA-sequencing to interrogate aging-related changes in the HFSCs. Surprisingly, although numbers declined, aging HFSCs were present, maintained their identity, and showed no overt signs of shifting to an epidermal fate. However, they did exhibit prevalent transcriptional changes particularly in extracellular matrix genes, and this was accompanied by profound structural perturbations in the aging SC niche. Moreover, marked age-related changes occurred in many nonepithelial cell types, including resident immune cells, sensory neurons, and arrector pili muscles. Each of these SC niche components has been shown to influence HF regeneration. When we performed skin injuries that are known to mobilize young HFSCs to exit their niche and regenerate HFs, we discovered that aged skin is defective at doing so. Interestingly, however, in transplantation assays in vivo, aged HFSCs regenerated HFs when supported with young dermis, while young HFSCs failed to regenerate HFs when combined with aged dermis. Together, our findings highlight the importance of SC:niche interactions and favor a model where youthfulness of the niche microenvironment plays a dominant role in dictating the properties of its SCs and tissue health and fitness.

Heme oxygenase-1 deficiency triggers exhaustion of hematopoietic stem cells

While intrinsic changes in aging hematopoietic stem cells (HSCs) are well characterized, it remains unclear how extrinsic factors affect HSC aging. Here, we demonstrate that cells in the niche-endothelial cells (ECs) and CXCL12-abundant reticular cells (CARs)-highly express the heme-degrading enzyme, heme oxygenase 1 (HO-1), but then decrease its expression with age. HO-1-deficient animals (HO-1-/- ) have altered numbers of ECs and CARs that produce less hematopoietic factors. HSCs co-cultured in vitro with HO-1-/- mesenchymal stromal cells expand, but have altered kinetic of growth and differentiation of derived colonies. HSCs from young HO-1-/- animals have reduced quiescence and regenerative potential. Young HO-1-/- HSCs exhibit features of premature exhaustion on the transcriptional and functional level. HO-1+/+ HSCs transplanted into HO-1-/- recipients exhaust their regenerative potential early and do not reconstitute secondary recipients. In turn, transplantation of HO-1-/- HSCs to the HO-1+/+ recipients recovers the regenerative potential of HO-1-/- HSCs and reverses their transcriptional alterations. Thus, HSC-extrinsic activity of HO-1 prevents HSCs from premature exhaustion and may restore the function of aged HSCs.

Poor old pores-The challenge of making and maintaining nuclear pore complexes in aging

The nuclear pore complex (NPC) is the sole gateway to the nuclear interior, and its function is essential to all eukaryotic life. Controlling the functionality of NPCs is a tremendous challenge for cells. Firstly, NPCs are large structures, and their complex assembly does occasionally go awry. Secondly, once assembled, some components of the NPC persist for an extremely long time and, as a result, are susceptible to accumulate damage. Lastly, a significant proportion of the NPC is composed of intrinsically disordered proteins that are prone to aggregation. In this review, we summarize how the quality of NPCs is guarded in young cells and discuss the current knowledge on the fate of NPCs during normal aging in different tissues and organisms. We discuss the extent to which current data supports a hypothesis that NPCs are poorly maintained during aging of nondividing cells, while in dividing cells the main challenge is related to the assembly of new NPCs. Our survey of current knowledge points toward NPC quality control as an important node in aging of both dividing and nondividing cells. Here, the loss of protein homeostasis during aging is central and the NPC appears to both be impacted by, and to drive, this process.

Targeting Immunophenotypic Markers on Leukemic Stem Cells: How Lessons from Current Approaches and Advances in the Leukemia Stem Cell (LSC) Model Can Inform Better Strategies for Treating Acute Myeloid Leukemia (AML)

Therapies targeting cell-surface antigens in acute myeloid leukemia (AML) have been tested over the past 20 years with limited improvement in overall survival. Recent advances in the understanding of AML pathogenesis support therapeutic targeting of leukemia stem cells as the most promising avenue toward a cure. In this review, we provide an overview of the evolving leukemia stem cell (LSC) model, including evidence of the cell of origin, cellular and molecular disease architecture, and source of relapse in AML. In addition, we explore limitations of current targeted strategies utilized in AML and describe the various immunophenotypic antigens that have been proposed as LSC-directed therapeutic targets. We draw lessons from current approaches as well as from the (pre)-LSC model to suggest criteria that immunophenotypic targets should meet for more specific and effective elimination of disease-initiating clones, highlighting in detail a few targets that we suggest fit these criteria most completely.

Gold Nanoparticles as a Computed Tomography Marker for Stem Cell Tracking

Stem cell tracking is an essential prerequisite for effective stem cell therapy. Computed tomography (CT) imaging technique is an emerging quantitative tool to detect real time distribution of transplanted cells. Most of CT labels based on the high atomic number (Z) materials have concern over biocompatibility. The present book chapter describes a protocol for the use of biocompatible gold nanoparticles as a CT marker for efficient labeling of mesenchymal stem cells (MSCs) and subsequent cell tracking in rodent models.

Acute Myeloid Leukemia: Aging and Epigenetics

Acute myeloid leukemia (AML) is an aggressive hematological disorder mainly affecting people of older age. AML initiation is primarily attributed to mutations in crucial cellular regulators such as epigenetic factors, transcription factors, and signaling genes. AML’s aggressiveness and responsiveness to treatment depends on the specific cell type where leukemia first arose. Aged hematopoietic cells are often genetically and/or epigenetically altered and, therefore, present with a completely different cellular context for AML development compared to young cells. In this review, we summarize key aspects of AML development, and we focus, in particular, on the contribution of cellular aging to leukemogenesis and on current treatment options for elderly AML patients. Hematological disorders and leukemia grow exponentially with age. So far, with conventional induction therapy, many elderly patients experience a very poor overall survival rate requiring substantial social and medical costs during the relatively few remaining months of life. The global population’s age is increasing rapidly without an acceptable equal growth in therapeutic management of AML in the elderly; this is in sharp contrast to the increase in successful therapies for leukemia in younger patients. Therefore, a focus on the understanding of the biology of aging in the hematopoietic system, the development of appropriate research models, and new therapeutic approaches are urged.

Somatic Mutations Reveal Lineage Relationships and Age-Related Mutagenesis in Human Hematopoiesis

Mutation accumulation during life can contribute to hematopoietic dysfunction; however, the underlying dynamics are unknown. Somatic mutations in blood progenitors can provide insight into the rate and processes underlying this accumulation, as well as the developmental lineage tree and stem cell division numbers. Here, we catalog mutations in the genomes of human-bone-marrow-derived and umbilical-cord-blood-derived hematopoietic stem and progenitor cells (HSPCs). We find that mutations accumulate gradually during life with approximately 14 base substitutions per year. The majority of mutations were acquired after birth and could be explained by the constant activity of various endogenous mutagenic processes, which also explains the mutation load in acute myeloid leukemia (AML). Using these mutations, we construct a developmental lineage tree of human hematopoiesis, revealing a polyclonal architecture and providing evidence that developmental clones exhibit multipotency. Our approach highlights features of human native hematopoiesis and its implications for leukemogenesis.

The role of cellular senescence in diabetes mellitus and osteoporosis: molecular pathways and potential interventions

The improving effectiveness of health care leads inevitably to a rapid increase in the elderly population worldwide. At advanced ages, however, people experience chronic disabilities, which significantly increase the social and economic burden while curtailing survival, independence, and quality of life of the aging population. As aging is a multifactorial process, apart from genetic predisposition, other environmental factors, such as chronic sterile inflammation and cellular senescence, contribute as crucial participants and have been targeted to reverse their deleterious effects on tissue homeostasis and functional integrity. Cellular senescence refers to the essentially irreversible inhibition of cellular proliferation when cells are subjected to extrinsic or endogenous stress. Although the process of cellular senescence has long been known, recent evidence demonstrated that it characterizes many aging phenotypes and that elimination of senescent cells at the tissue level can improve age-related tissue dysfunction. These observations have renewed scientific interest in possible therapeutic interventions. Two major chronic diseases associated with aging that impose an enormous burden on global health systems are type 2 diabetes and osteoporosis. This review presents current data on (i) the underlying molecular mechanisms of cellular senescence, (ii) its relationship to these two endocrine diseases that are today prevalent worldwide, and (iii) future prospects of targeted intervention with the aim of simultaneously improving the progression and prognosis of these serious problems of aging.

Replicative cellular age distributions in compartmentalized tissues

The cellular age distribution of hierarchically organized tissues can reveal important insights into the dynamics of cell differentiation and self-renewal and associated cancer risks. Here, we examine the effect of progenitor compartments with varying differentiation and self-renewal capacities on the resulting observable distributions of replicative cellular ages. We find that strongly amplifying progenitor compartments, i.e. compartments with high self-renewal capacities, substantially broaden the age distributions which become skewed towards younger cells with a long tail of few old cells. For several of these strongly amplifying compartments, the age distribution becomes virtually independent of the influx from the stem cell compartment. By contrast, if tissues are organized into many downstream compartments with low self-renewal capacity, the shape of the replicative cell distribution in more differentiated compartments is dominated by stem cell dynamics with little added variation. In the limiting case of a strict binary differentiation tree without self-renewal, the shape of the output distribution becomes indistinguishable from that of the input distribution. Our results suggest that a comparison of cellular age distributions between healthy and cancerous tissues may inform about dynamical changes within the hierarchical tissue structure, i.e. an acquired increased self-renewal capacity in certain tumours. Furthermore, we compare our theoretical results to telomere length distributions in granulocyte populations of 10 healthy individuals across different ages, highlighting that our theoretical expectations agree with experimental observations.

Transferrin receptor 1-mediated iron uptake plays an essential role in hematopoiesis

Transferrin receptor 1 (Tfr1) mediates the endocytosis of diferric transferrin in order to transport iron, and Tfr1 has been suggested to play an important role in hematopoiesis. To study the role of Tfr1 in hematopoiesis, we generated hematopoietic stem cell (HSC) specific Tfr1 knockout mice. We found that Tfr1 conditional knockout mice reached full term but died within one week of birth. Further analyses revealed that Tfr1-deficient HSC had impaired development of all hematopoietic progenitors except thrombocytes and B lymphocytes. In addition, Tfr1-deficient cells had cellular iron deficiency, which blocked the proliferation and differentiation of hematopoietic precursor cells, attenuated the commitment of hematopoietic lineages, and reduced the regeneration potential of HSC. Notably, hemin rescued the colony-forming capacity of Tfr1-deficient HSC, whereas expressing a mutant Tfr1 that lacks the protein's iron-transporting capacity failed to rescue hematopoiesis. These findings provide direct evidence that Tfr1 is essential for hematopoiesis through binding diferric transferrin to supply iron to cells.

The paradox of metabolism in quiescent stem cells

The shift between a proliferating and a nonproliferating state is associated with significant changes in metabolic needs. Proliferating cells tend to have higher metabolic rates, and their metabolic profiles facilitate biosynthesis, as compared to those of nondividing cells of the same sort. Recent studies have elucidated specific molecules that control metabolic changes while cells shift between proliferation and quiescence. Embryonic stem cells, which are rapidly proliferating, tend to have metabolic patterns that are similar to those of nonstem cells in a proliferative state. Moreover, although adult stem cells tend to be quiescent, their metabolic profiles have been reported in multiple organs to more closely resemble those of proliferating than those of nondividing cells in some respects. The findings raise questions about whether there are metabolic profiles that are required for stemness, and whether these profiles relate to the metabolic properties that may be required for quiescence. Here, we review the literature on how metabolism changes upon commitment to proliferation and compare the proliferating and nonproliferating metabolic states of differentiated cells and embryonic and adult stem cells.

Implications of TERT promoter mutations and telomerase activity in urothelial carcinogenesis

Telomerase activity imparts eukaryotic cells with unlimited proliferation capacity, one of the cancer hallmarks. Over 90% of human urothelial carcinoma of the bladder (UCB) tumours are positive for telomerase activity. Telomerase activation can occur through several mechanisms. Mutations in the core promoter region of the human telomerase reverse transcriptase gene (TERT) cause telomerase reactivation in 60-80% of UCBs, whereas the prevalence of these mutations is lower in urothelial cancers of other origins. TERT promoter mutations are the most frequent genetic alteration across all stages of UCB, indicating a strong selection pressure during neoplastic transformation. TERT promoter mutations could arise during regeneration of normal urothelium and, owing to consequential telomerase reactivation, might be the basis of UCB initiation, which represents a new model of urothelial cancer origination. In the future, TERT promoter mutations and telomerase activity might have diagnostic and therapeutic applications in UCB.

Immunohistological staining of unknown chemokine RANTES/CCL5 expression in jawbone marrow defects-osteoimmunology and disruption of bone remodeling in clinical case studies targeting on predictive preventive personalized medicine

Background

Fatty degenerative osteonecrosis in the medullary spaces of the jawbone (FDOJ) may be identified as a lesser known source of RANTES/CCL5 (R/C) overexpression. The chemokine R/C also interferes with bone metabolism leading to osteolysis in areas affected by FDOJ. Many dental surgeries require functioning repair mechanisms and these may be disrupted by R/C overexpression.

Objective

To clarify the way in which R/C expression from adipocytes in FDOJ causes a disturbance in osteogenesis and impacts on medullary stem cells by investigating the detection of R/C expression with immunochemical staining.

Materials and methods

We examined the tissue samples of 449 patients with FDOJ to assess the level of the chemokine R/C using bead-based Luminex® analysis. In six clinical case studies of FDOJ, we compared bone density, histological findings, R/C expression, and immunohistochemical staining.

Results

R/C is overexpressed by up to 30-fold in the 449 FDOJ cases when compared with healthy jawbone samples. The comparison of the six clinical cases consistently shows greatly reduced bone density, (i.e., osteolysis), but varies in terms of the level of agreement across the other three parameters.

Discussion

R/C from FDOJ sources may be implicated in several immune responses and considered a key pathogenetic pathway for increased adipogenesis rather than desirable osteogenesis. Adipocytes pathogenetically act via R/C expression in local FDOJ and systemically on the immune system.

Conclusion

R/C may be regarded as an important trigger for possible pathological developments in the fate of hematopoietic stem cells. FDOJ is not a rigidly uniform process but reflects changing stages of development. The absence of correlating findings should not be interpreted as a misdiagnosis. It seems appropriate to direct further research in the field of “maxillo–mandibular osteoimmunology” focusing on R/C overexpression in FDOJ areas. This may contribute to the development of personalized strategies in preventive medicine.