Novel mechanism of Wnt signalling inhibition mediated by Dickkopf-1 interaction with LRP6/Arrow

Anticancer signal transduction pathways of selenium nanoparticles in mouse colorectal cancer model

Despite significant advances in the treatment of colon cancer, this disease is extremely common, often requiring serious surgery followed by long-term drug treatment. Colon and rectal cancer remain dangerous forms of cancer due to the high degree of metastasis. The development and study of the effectiveness of anticancer drugs based on nanoparticles is an urgent task of modern biomedicine. Of particular interest are attempts to move research from the in vitro level to the in vivo level of preclinical studies. In the presented study, mice were subcutaneously implanted with MC-38 cell line, a tumor was grown, and selenium nanoparticles (SeNPs) with a diameter of 100 nm obtained using the laser ablation method were administered intraperitoneally. Using morphometric measurements, it was found that injections of 1 μg/g or 10 μg/g SeNPs inhibited weight loss of mice during cancer development, reduced tumor size by 2-2.5 times, and suppressed metastasis by 1.5-3 times. Analysis of selenium levels in mouse blood, liver and tumor samples by atomic absorption spectrometry after the end of SeNPs treatment showed that the nanoparticles increased selenium levels in the blood and liver of mice without a significant dose-dependence, whereas in tumors a dose-dependent increase in selenium concentration was detected from the concentration of nanoparticles, with 10 μg/g SeNPs causing a more pronounced increase in selenium concentration. Using PCR and Western blot analysis, it was possible to establish that SeNPs injections led to an increase in the expression of genes encoding anti-inflammatory and anti-hypoxic proteins, but reduced the expression of antioxidant selenium-containing proteins and proteins responsible for the proliferation of cancer cells. Both concentrations of SeNPs led to similar effects, but increasing the concentration of nanoselenium to 10 μg/g affected the expression of a larger number of genes and the effects on expression were more "bright". Thus, the complex of presented experiments showed that injections of selenium nanoparticles in concentrations of 1 μg/g or 10 μg/g are capable to transport by the bloodstream and accumulating in the highest concentration in colon adenocarcinoma, compared with liver, which indicates the targeting of SeNPs in relation to tumors even without functionalization by specific molecules. As a result, there was a change in the expression patterns of genes and a number of proteins, and as a result, there was a decrease in tumor volume, normalization of mouse weight and maintenance of positive dynamics throughout the entire observation period.

Dickkopf-1 promotes tumor progression of gefitinib- resistant non-small cell lung cancer through cancer cell-fibroblast interactions

BACKGROUND

Cancer cell-secreted proteins play a critical role in tumor progression and chemoresistance by influencing intercellular interactions within the tumor microenvironment. Investigating the intratumoral functions of these secretory proteins may provide insights into understanding and treating chemoresistant cancers. This study aims to identify potential anticancer target(s) in gefitinib-resistant non-small cell lung cancer (NSCLC), with a focus on secretory proteins and their effects on intercellular interactions.

METHODS

Differentially expressed secretory proteins were identified in gefitinib-resistant human NSCLC cell lines (PC9-GR and HCC827-GR), revealing an elevation in Dickkopf-1 (DKK1) expression and secretion. To elucidate the role of DKK1 in gefitinib-resistant cancer, the anticancer effects of a neutralizing antibody against DKK1 were evaluated in tumors comprising either cancer cells alone or cancer cells co-injected with human lung fibroblasts (MRC-5). Following the confirmation of the importance of cancer cell-fibroblast interactions in the protumorigenic activity of DKK1, the fibroblast traits modulated by DKK1 were further analyzed.

RESULTS

Gefitinib-resistant NSCLC cells exhibited increased DKK1 protein expression. Although elevated DKK1 levels were linked to poor prognosis, DKK1 did not directly affect cancer cell proliferation. However, DKK1 blockade showed significant anticancer effects in gefitinib-resistant tumors containing lung fibroblasts, suggesting that DKK1's pro-tumorigenic roles are mediated through cancer cell-fibroblast interactions. DKK1 altered fibroblast characteristics, enhancing inflammatory fibroblast traits while diminishing myofibroblast traits in tumor microenvironment. These DKK1-induced changes were mediated via activation of the c-JUN pathway in fibroblasts. Moreover, DKK1 was identified as a potential anticancer target across various cancer types beyond gefitinib-resistant lung cancer.

CONCLUSIONS

This study clarifies that DKK1 mediates interactions between cancer cells and fibroblasts in gefitinib-resistant lung cancer, contributing to tumor progression. Therefore, we propose DKK1 as a promising anticancer target for the treatment of gefitinib-resistant NSCLC.

Wnt Signaling Inhibitors as Therapeutic Approach in Ischemic Heart Disease

Wnt (wingless-type MMTV integration site family) signaling is an evolutionary conserved system highly active during embryogenesis, but in adult hearts has low activities under normal conditions. It is essential for a variety of physiological processes including stem cell regeneration, proliferation, migration, cell polarity, and morphogenesis, thereby ensuring homeostasis and regeneration of cardiac tissue. Its dysregulation and excessive activation during pathological conditions leads to morphological and functional changes in the heart resulting in impaired myocardial regeneration under pathological conditions such as myocardial infarction, heart failure, and coronary artery disease. Several groups of Wnt inhibitors have demonstrated the ability to modulate the Wnt pathway and thereby significantly reduce fibrosis and improve cardiac function after myocardial ischemia. Their inhibitory effect can be realized at multiple levels, which include the inhibition of Wnt ligands, the inhibition of Frizzled receptors, the stabilization of the β-catenin destruction complex, and the disruption of nuclear β-catenin interactions. In this review, we overview the function of Wnt signaling in responses of cardiac cells to pathological conditions, especially ischemic heart disease, with an emphasis on the use of inhibitors of this signaling as a therapeutic approach. Finally, we summarize the current knowledge about the potential of the targeting of Wnt signaling in therapeutic applications.

Bone Disease in Primary Hyperparathyroidism-Changes Occurring in Bone Metabolism and New Potential Treatment Strategies

Primary hyperparathyroidism (PHPT) is a common endocrinopathy, predominantly caused by a single parathyroid adenoma that is responsible for the excessive secretion of parathyroid hormone (PTH)-the hallmark of disease. Excess of this hormone causes remarkable changes in bone metabolism, including an increased level of bone remodeling with a predominance of bone resorption. Those changes lead to deterioration of bone structure and density, especially in cortical bone. The main treatment for PHPT is surgical removal of the adenoma, which normalizes PTH levels and terminates the progression of bone disease and leads to its regeneration. However, because not all the patients are suitable candidates for surgery, alternative therapies are needed. Current non-surgical treatments targeting bone disease secondary to PHPT include bisphosphonates and denosumab. Those antiresorptives prevent further bone loss, but they lack the ability to regenerate already degraded bone. There is ongoing research to find targeted drugs capable of halting resorption alongside stimulating bone formation. This review presents the advancements in understanding the molecular mechanisms responsible for bone disease in PHPT and assesses the efficacy of new potential therapeutic approaches (e.g., allosteric inhibitors of the PTH receptor, V-ATPase, or cathepsin inhibitors) aimed at mitigating bone loss and enhancing bone regeneration in affected patients.

Dickkopf-related Protein 2 Promotes Hair Growth by Upregulating the Wnt/β-catenin Signaling Pathway in Human Dermal Papilla Cells

BACKGROUND

The Wnt/β-catenin signaling pathway is crucial for the development, initiation, and growth of hair follicles (HFs). The Dickkopf-related protein (DKK) gene family encodes secreted proteins modulating the Wnt/β-catenin signaling pathway. Studies have reported that DKK1 promotes the regression of HFs and serves as a pathogenic mediator in male pattern baldness. However, the role of DKK2 on human hair growth has not yet been explored.

OBJECTIVE

This study investigates direct effect of DKK2 on hair growth using human dermal papilla cell (DPC) cultures and ex vivo human HF organ cultures.

METHODS

To elucidate the effect of DKK2 on hair growth, we examined the effect of recombinant human DKK2 (rhDKK2) treatment on cell viability, expression of mRNA and protein related to the Wnt/β-catenin signaling pathway, and cell growth in cultured human DPCs. We also performed ex vivo organ culture of HFs with rhDKK2 and measured changes in hair shaft length for 8 days.

RESULTS

Treatment with rhDKK2 led to a dose-dependent rise in the proliferation of human DPCs (p<0.05), reaching levels comparable to those induced by 1 μM minoxidil. Moreover, rhDKK2 increased the expression of Wnt/β-catenin target genes, phosphorylated extracellular signal-regulated kinase, and cyclin-D1; it also increased the BAX-to-Bcl-2 ratio and downregulated the bone morphogenetic protein 2 gene. In human HF organ cultures, relative to the control treatment, rhDKK2 treatment significantly increased hair shaft elongation (p<0.01).

CONCLUSION

Our results indicate that rhDKK2 could promote hair growth by facilitating the proliferation of human DPCs through activation of the Wnt/β-catenin signaling pathway.

Identification of XD23 as a potent inhibitor of osteosarcoma via downregulation of DKK1 and activation of the WNT/β-catenin pathway

Osteosarcoma, the most prevalent malignant bone tumor, is notorious for its aggressive growth and invasiveness. The highly mutable genome of osteosarcoma has made identifying a key oncogene challenging, hindering the development of targeted treatments. Our study validates the effectiveness of XD23, an anti-cancer agent we previously identified, in curbing osteosarcoma proliferation, metastasis, EMT differentiation, and bone destruction and promoting osteosarcoma apoptosis. It further elucidated that XD23 thwarts osteosarcoma by suppressing DKK1 expression, which in turn activates the WNT-β/Catenin pathway. This research presents the concrete evidence of DKK1's involvement in osteosarcoma development, offering a foundation for the development of DKK1 inhibitors as novel treatments for this disease.

Functional Insights in PLS3-Mediated Osteogenic Regulation

Plastin-3 (PLS3) encodes T-plastin, an actin-bundling protein mediating the formation of actin filaments by which numerous cellular processes are regulated. Loss-of-function genetic defects in PLS3 are reported to cause X-linked osteoporosis and childhood-onset fractures. However, the molecular etiology of PLS3 remains elusive. Functional compensation by actin-bundling proteins ACTN1, ACTN4, and FSCN1 was investigated in zebrafish following morpholino-mediated pls3 knockdown. Primary dermal fibroblasts from six patients with a PLS3 variant were also used to examine expression of these proteins during osteogenic differentiation. In addition, Pls3 knockdown in the murine MLO-Y4 cell line was employed to provide insights in global gene expression. Our results showed that ACTN1 and ACTN4 can rescue the skeletal deformities in zebrafish after pls3 knockdown, but this was inadequate for FSCN1. Patients' fibroblasts showed the same osteogenic transdifferentiation ability as healthy donors. RNA-seq results showed differential expression in Wnt1, Nos1ap, and Myh3 after Pls3 knockdown in MLO-Y4 cells, which were also associated with the Wnt and Th17 cell differentiation pathways. Moreover, WNT2 was significantly increased in patient osteoblast-like cells compared to healthy donors. Altogether, our findings in different bone cell types indicate that the mechanism of PLS3-related pathology extends beyond actin-bundling proteins, implicating broader pathways of bone metabolism.

Why Is Wnt/β-Catenin Not Yet Targeted in Routine Cancer Care?

Despite significant progress in cancer prevention, screening, and treatment, the still limited number of therapeutic options is an obstacle towards increasing the cancer cure rate. In recent years, many efforts were put forth to develop therapeutics that selectively target different components of the oncogenic Wnt/β-catenin signaling pathway. These include small molecule inhibitors, antibodies, and more recently, gene-based approaches. Although some of them showed promising outcomes in clinical trials, the Wnt/β-catenin pathway is still not targeted in routine clinical practice for cancer management. As for most anticancer treatments, a critical limitation to the use of Wnt/β-catenin inhibitors is their therapeutic index, i.e., the difficulty of combining effective anticancer activity with acceptable toxicity. Protecting healthy tissues from the effects of Wnt/β-catenin inhibitors is a major issue due to the vital role of the Wnt/β-catenin signaling pathway in adult tissue homeostasis and regeneration. In this review, we provide an up-to-date summary of clinical trials on Wnt/β-catenin pathway inhibitors, examine their anti-tumor activity and associated adverse events, and explore strategies under development to improve the benefit/risk profile of this therapeutic approach.

Wnt/β-catenin signaling components and mechanisms in bone formation, homeostasis, and disease

Wnts are secreted, lipid-modified proteins that bind to different receptors on the cell surface to activate canonical or non-canonical Wnt signaling pathways, which control various biological processes throughout embryonic development and adult life. Aberrant Wnt signaling pathway underlies a wide range of human disease pathogeneses. In this review, we provide an update of Wnt/β-catenin signaling components and mechanisms in bone formation, homeostasis, and diseases. The Wnt proteins, receptors, activators, inhibitors, and the crosstalk of Wnt signaling pathways with other signaling pathways are summarized and discussed. We mainly review Wnt signaling functions in bone formation, homeostasis, and related diseases, and summarize mouse models carrying genetic modifications of Wnt signaling components. Moreover, the therapeutic strategies for treating bone diseases by targeting Wnt signaling, including the extracellular molecules, cytosol components, and nuclear components of Wnt signaling are reviewed. In summary, this paper reviews our current understanding of the mechanisms by which Wnt signaling regulates bone formation, homeostasis, and the efforts targeting Wnt signaling for treating bone diseases. Finally, the paper evaluates the important questions in Wnt signaling to be further explored based on the progress of new biological analytical technologies.

Design, synthesis and anti-osteosarcoma activity study of novel pyrido[2,3-d]pyrimidine derivatives by inhibiting DKK1-Wnt/β-catenin pathway

Osteosarcoma is a common primary malignant bone tumor in adolescents. Wnt/β-catenin has been proved to play a pro-oncogenic role and was overactivated in osteosarcoma. Therefore, this pathway has become an interesting therapeutic target for osteosarcoma. Herein we report the design, synthesis and biological activities of a series of novel pyrido[2,3-d]pyrimidine derivatives based on our previous work. Among these, the representative compound 2-{[1,3-dimethyl-7-(4-methylpiperazin-1-yl)-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-5-yl]amino}-N-[4-(trifluoromethoxy)phenyl]acetamide (7m) has exhibited good antiproliferative activity towards 143B and MG63 cells with good selectivity over non-cancerous HSF cells. In the assay of Ca2+ concentration, the compound 7m increased the intracellular Ca2+ concentration in 143B cells. In addition, the expression of DKK1 increased, and that of p-β-catenin decreased by 7m treatment. Finally, the Hoechst 33,342 staining, Annexin-FITC/PI staining and mitochondrial fluorescence staining have clearly demonstrated that compound 7m induced apoptosis in 143B cells.

17β-estradiol mitigates the inhibition of SH-SY5Y cell differentiation through WNT1 expression

17β-estradiol (E2) and canonical WNT-signaling represent crucial regulatory pathways for microtubule dynamics and synaptic formation. However, it is unclear yet whether E2-induced canonical WNT ligands have significant impact on neurogenic repair under inflammatory condition. In this study, first, we prepared the chronic activated-microglial-conditioned media, known to be comprised of neuro-inflammatory components. Long term exposure of microglial conditioned media to SH-SY5Y cells showed a negative impact on differentiation markers, microtubule associated protein-2 (MAP2) and synaptophysin (SYP), which was successfully rescued by pre and co-treatment of 10 nM 17β-estradiol. The inhibition of estrogen receptors, ERα and ERβ significantly blocked the E2-mediated recovery in the expression of differentiation marker, SYP. Furthermore, the inflammatory inhibition of canonical signaling ligand, WNT1 was also found to be rescued by E2. To our surprise, E2 was unable to replicate this success with β-catenin, which is considered to be the intracellular transducer of canonical WNT signaling. However, WNT antagonist - Dkk1 blocked the E2-mediated recovery in the expression of the differentiation marker, MAP2. Therefore, our data suggests that E2-mediated recovery in SH-SY5Y differentiation follows a divergent pathway from the conventional canonical WNT signaling pathway, which seems to regulate microtubule stability without the involvement of β-catenin. This mechanism provides fresh insight into how estradiol contributes to the restoration of differentiation marker proteins in the context of chronic neuroinflammation.

The Roles of WNT Signaling Pathways in Skin Development and Mechanical-Stretch-Induced Skin Regeneration

The WNT signaling pathway plays a critical role in a variety of biological processes, including development, adult tissue homeostasis maintenance, and stem cell regulation. Variations in skin conditions can influence the expression of the WNT signaling pathway. In light of the above, a deeper understanding of the specific mechanisms of the WNT signaling pathway in different physiological and pathological states of the skin holds the potential to significantly advance clinical treatments of skin-related diseases. In this review, we present a comprehensive analysis of the molecular and cellular mechanisms of the WNT signaling pathway in skin development, wound healing, and mechanical stretching. Our review sheds new light on the crucial role of the WNT signaling pathway in the regulation of skin physiology and pathology.

Deep Proteome of the Developing Chick Midbrain

The epithelial-to-mesenchymal transition (EMT) and migration of cranial neural crest cells within the midbrain are critical processes that permit proper craniofacial patterning in the early embryo. Disruptions in these processes not only impair development but also lead to various diseases, underscoring the need for their detailed understanding at the molecular level. The chick embryo has served historically as an excellent model for human embryonic development, including cranial neural crest cell EMT and migration. While these developmental events have been characterized transcriptionally, studies at the protein level have not been undertaken to date. Here, we applied mass spectrometry (MS)-based proteomics to establish a deep proteomics profile of the chick midbrain region during early embryonic development. Our proteomics method combines optimal lysis conditions, offline fractionation, separation on a nanopatterned stationary phase (μPAC) using nanoflow liquid chromatography, and detection using quadrupole-ion trap-Orbitrap tribrid high-resolution tandem MS. Identification of >5900 proteins and >450 phosphoproteins in this study marks the deepest coverage of the chick midbrain proteome to date. These proteins have known roles in pathways related to neural crest cell EMT and migration such as signaling, proteolysis/extracellular matrix remodeling, and transcriptional regulation. This study offers valuable insight into important developmental processes occurring in the midbrain region and demonstrates the utility of proteomics for characterization of tissue microenvironments during chick embryogenesis.

Molecular Evolution and Protein Structure Variation of Dkk Family

Dkks have inhibitory effects on the Wnt signaling pathway, which is involved in the development of skin and its appendages and the regulation of hair growth. The nucleotide sequences were compared and analyzed to further investigate the relationship between the structure and function of the Dkk gene family and vertebrate epidermal hair. The analysis of the molecular evolution of the Dkk family revealed that the evolution rate of the genes changed significantly after speciation, with the Aves and Reptilia branches showing accelerated evolution. Additionally, positive selection was observed at specific sites. The tertiary structure of the protein was also predicted. The analysis of the functional divergence of the Dkk family revealed that the functional divergence coefficient of each gene was greater than 0, with most of the functional divergence sites were located in the Cys-2 domain and a few in the Cys-1 domain. This suggests that the amino acid and functional divergence sites may play a role in regulating the binding of the Dkk family to LRP5/6, and thus affect the inhibition of Wnt signaling, leading to different functions of Dkk1, Dkk2, and Dkk4 in the development of skin hair follicles. In addition, the Dkk families of Aves and Reptilia may have undergone adaptive evolution and functional divergence.

Extremely hair follicle density is associated with a significantly different cecal microbiota in rex rabbits

It has become increasingly clear that gut microbiota and skin are interconnected since the discovery of the 'gut-brain-skin' axis. Hair follicles (HFs) are skin microorganisms, but few studies have investigated their relationship to gut microbiota. Hence, we hypothesize that HFs have a close relationship with the gut, similarly to what was reported for the skin. Using rex rabbits as an animal model, one hundred healthy half-sibling rex rabbits were selected for the experiment, and 16 s rRNA gene sequencing was performed on the cecal microbiota of nine rabbits with the extremely high (HS) and low (LS) hair density (n = 9 per group) to determine differences between the composition and function of these communities. In comparison with the LS group, several alpha diversity index values were significantly lower in the HS group, although the higher variation in species composition in the HS group. Additionally, species diversity and abundance differed significantly in the cecum microbiota of HS and LS rabbits. Further, primary and secondary HF density was significantly correlated with the families Muribaculaceae and Bacteroidaceae, and genera Blautia, Bacteroides and Desulfovibrio. In particular, Muribaculaceae, Bacteroidaceae, Blautia and Bacteroides may support the development of HFs. Moreover, the expression of WNT4, WNT10a, WNT10b, CTNNB1 (β-catenin) and LEF1 in the skin was significantly higher in the HS group compared with the LS group. Altogether, the results of this study suggest that the extremely high density of HF in rabbits is associated with a significantly different microbiota diversity and community structure, and the Wnt/β-catenin signalling pathway was activated in the HS group. Thus, key bacteria may promote the development of HF.

Expression of DKK1 in Endometrial Endometrioid Carcinoma and Its Correlation with Wnt/β-catenin Signalling Pathway

Objectives

Endometrial cancer is the most prevalent form of cancer affecting female reproductive organs. The most common histologic type, endometrioid carcinoma, accounts for 75-80% of all endometrial cancer cases. Studies on DKK1 expression profiles and their inhibitory role in the Wnt signalling pathway in the genesis and development of endometrial carcinoma are scarce. This study aimed to investigate DKK1 expression in endometrial carcinoma and its correlation with the Wnt/β-catenin pathway.

Methods

A total of 160 formalin-fixed paraffin-embedded samples were included in this study (50 cases of endometrial atypical hyperplasia, 50 cases of endometrioid endometrial carcinoma, 30 cases of proliferative endometrium and 30 cases of secretory endometrium). The expression patterns of DKK1, E-cadherin, β-catenin and c-Myc in endometrial atypical hyperplasia and carcinoma were investigated and compared with that of proliferative and secretory endometrium. Immunohistochemistry and analysis were performed from July 2018 to June 2020.

Results

A decreasing pattern of immunopositivity for DKK1, E-cadherin and β-catenin from proliferative/secretory endometrium to endometrial atypical hyperplasia and endometrioid carcinoma was found. Increasing c-Myc immunopositivity was noted from proliferative/secretory endometrium to endometrial atypical hyperplasia and endometrioid carcinoma. Moreover, decreasing DKK1 immunopositivity was well correlated with E-cadherin, β-catenin and c-Myc immunopositivity.

Conclusion

Decreasing DKK1 positivity from benign endometrium to endometrioid carcinoma suggests a negative regulatory function of DKK1 in endometrioid carcinoma. DKK1 is downregulated in the Wnt signalling pathway in endometrioid endometrial carcinoma. Therefore, DKK1 is promising as a biomarker for screening endometrioid carcinoma. Future studies should examine the reactivation of the DKK1 gene, which may be a valuable strategy for antagonising the Wnt signalling pathway.

Pediatric Type 1 Diabetes: Mechanisms and Impact of Technologies on Comorbidities and Life Expectancy

Type 1 diabetes (T1D) is one of the most common chronic diseases in childhood, with a progressively increasing incidence. T1D management requires lifelong insulin treatment and ongoing health care support. The main goal of treatment is to maintain blood glucose levels as close to the physiological range as possible, particularly to avoid blood glucose fluctuations, which have been linked to morbidity and mortality in patients with T1D. Indeed, the guidelines of the International Society for Pediatric and Adolescent Diabetes (ISPAD) recommend a glycated hemoglobin (HbA1c) level < 53 mmol/mol (<7.0%) for young people with T1D to avoid comorbidities. Moreover, diabetic disease strongly influences the quality of life of young patients who must undergo continuous monitoring of glycemic values and the administration of subcutaneous insulin. In recent decades, the development of automated insulin delivery (AID) systems improved the metabolic control and the quality of life of T1D patients. Continuous subcutaneous insulin infusion (CSII) combined with continuous glucose monitoring (CGM) devices connected to smartphones represent a good therapeutic option, especially in young children. In this literature review, we revised the mechanisms of the currently available technologies for T1D in pediatric age and explored their effect on short- and long-term diabetes-related comorbidities, quality of life, and life expectation.

CDK9 inhibitors downregulate DKK1 expression to suppress the metastatic potential of HCC cells

BACKGROUND

Elevated expression of Dickkopf-1 (DKK1) is frequently observed in hepatocellular carcinoma (HCC) patients with poor clinical outcomes. Several reports indicating the functional involvement of DKK1 in HCC progression have suggested DKK1 as a promising therapeutic target for HCC.

OBJECTIVE

In this study, to develop an efficient way to target DKK1, we assessed the effect of CDK9 inhibitors on DKK1 expression linked to metastatic movement of HCC.

METHODS

The expression of DKK1 in CDK9 inhibitor-treated HCC cells was measured by western blot, ELISA and quantitative real-time reverse transcription PCR. Wound healing assay, migration assay, invasion assay and western blot were examined to evaluate the functional role of DKK1 in CDK9 inhibitors-treated HCC.

RESULTS

Inactivation of CDK9 either by a catalytic inhibitor being clinically evaluated or by a specific CDK9 protein degrader largely downregulated DKK1 expression at the transcript and protein levels. In addition, CDK9 inhibitors suppressed the migration and invasion of HCC cells. We observed that ectopic high expression of DKK1 at least partially reversed the defects in metastatic movement of HCC cells mediated by CDK9 inhibitors. We further discovered that the DKK1-nuclear β-catenin axis associated with the metastatic potential of HCC cells was impaired by CDK9 inhibitors.

CONCLUSION

Taken together, our findings suggest that CDK9 inhibitors are potent tools to target DKK1, which can suppress the metastatic progression of HCC.

Extracellular Vesicles Derived from Three-Dimensional-Cultured Human Umbilical Cord Blood Mesenchymal Stem Cells Prevent Inflammation and Dedifferentiation in Pancreatic Islets

It is unclear whether extracellular vesicles (EVs) from mesenchymal stem cells (MSCs) have a direct protective effect on pancreatic islets. In addition, whether culturing MSCs in three dimensions (3D) instead of a monolayer (2D) can induce changes in the cargo of EVs that facilitate the polarization of macrophages into an M2 phenotype has not been investigated. We sought to determine whether EVs from MSCs cultured in 3D can prevent inflammation and dedifferentiation in pancreatic islets and, if so, whether the protective effect is superior to that of EVs from 2D MSCs. Human umbilical cord blood- (hUCB-) MSCs cultured in 3D were optimized according to cell density, exposure to hypoxia, and cytokine treatment based on the ability of the hUCB-MSC-derived EVs to induce the M2 polarization of macrophages. Islets isolated from human islet amyloid polypeptide (hIAPP) heterozygote transgenic mice were cultured in serum-deprived conditions with hUCB-MSC-derived EVs. EVs derived from 3D hUCB-MSCs had more abundant microRNAs involved in M2 polarization of macrophages and had an enhanced M2 polarization ability on macrophages, which was optimized when the 3D culture condition was 2.5 × 10⁴ cells per spheroid without preconditioning with hypoxia and cytokine exposure. When islets isolated from hIAPP heterozygote transgenic mice were cultured in serum-deprived conditions with hUCB-MSC-derived EVs, the EVs derived from 3D hUCB-MSCs suppressed the expression of proinflammatory cytokines and caspase-1 in pancreatic islets and increased the proportion of M2-polarized islet-resident macrophages. They improved glucose-stimulated insulin secretion, reduced the expression of Oct4 and NGN3, and induced the expression of Pdx1 and FoxO1. The greater suppression of IL-1β, NLRP3 inflammasome, caspase-1, and Oct4 and induction of Pdx1 and FoxO1 were found in islets cultured with the EVs derived from 3D hUCB-MSCs. In conclusion, EVs derived from 3D hUCB-MSCs optimized for M2 polarization attenuated nonspecific inflammation and preserved β-cell identity of pancreatic islets.

Aging and Bone Metabolism

Changes in bone architecture and metabolism with aging increase the likelihood of osteoporosis and fracture. Age-onset osteoporosis is multifactorial, with contributory extrinsic and intrinsic factors including certain medical problems, specific prescription drugs, estrogen loss, secondary hyperparathyroidism, microenvironmental and cellular alterations in bone tissue, and mechanical unloading or immobilization. At the histological level, there are changes in trabecular and cortical bone as well as marrow cellularity, lineage switching of mesenchymal stem cells to an adipogenic fate, inadequate transduction of signals during skeletal loading, and predisposition toward senescent cell accumulation with production of a senescence-associated secretory phenotype. Cumulatively, these changes result in bone remodeling abnormalities that over time cause net bone loss typically seen in older adults. Age-related osteoporosis is a geriatric syndrome due to the multiple etiologies that converge upon the skeleton to produce the ultimate phenotypic changes that manifest as bone fragility. Bone tissue is dynamic but with tendencies toward poor osteoblastic bone formation and relative osteoclastic bone resorption with aging. Interactions with other aging physiologic systems, such as muscle, may also confer detrimental effects on the aging skeleton. Conversely, individuals who maintain their BMD experience a lower risk of fractures, disability, and mortality, suggesting that this phenotype may be a marker of successful aging. © 2023 American Physiological Society. Compr Physiol 13:4355-4386, 2023.

Updates in the chronic kidney disease-mineral bone disorder show the role of osteocytic proteins, a potential mechanism of the bone-Vascular paradox, a therapeutic target, and a biomarker

The chronic kidney disease-mineral bone disorder (CKD-MBD) is a complex multi-component syndrome occurring during kidney disease and its progression. Here, we update progress in the components of the syndrome, and synthesize recent investigations, which suggest a potential mechanism of the bone-vascular paradox. The discovery that calcified arteries in chronic kidney disease inhibit bone remodeling lead to the identification of factors produced by the vasculature that inhibit the skeleton, thus providing a potential explanation for the bone-vascular paradox. Among the factors produced by calcifying arteries, sclerostin secretion is especially enlightening. Sclerostin is a potent inhibitor of bone remodeling and an osteocyte specific protein. Its production by the vasculature in chronic kidney disease identifies the key role of vascular cell osteoblastic/osteocytic transdifferentiation in vascular calcification and renal osteodystrophy. Subsequent studies showing that inhibition of sclerostin activity by a monoclonal antibody improved bone remodeling as expected, but stimulated vascular calcification, demonstrate that vascular sclerostin functions to brake the Wnt stimulation of the calcification milieu. Thus, the target of therapy in the chronic kidney disease-mineral bone disorder is not inhibition of sclerostin function, which would intensify vascular calcification. Rather, decreasing sclerostin production by decreasing the vascular osteoblastic/osteocytic transdifferentiation is the goal. This might decrease vascular calcification, decrease vascular stiffness, decrease cardiac hypertrophy, decrease sclerostin production, reduce serum sclerostin and improve skeletal remodeling. Thus, the therapeutic target of the chronic kidney disease-mineral bone disorder may be vascular osteoblastic transdifferentiation, and sclerostin levels may be a useful biomarker for the diagnosis of the chronic kidney disease-mineral bone disorder and the progress of its therapy.

Advances in the Pathophysiology of Thrombosis in Antiphospholipid Syndrome: Molecular Mechanisms and Signaling through Lipid Rafts

The pathological features of antiphospholipid syndrome (APS) are related to the activity of circulating antiphospholipid antibodies (aPLs) associated with vascular thrombosis and obstetric complications. Indeed, aPLs are not only disease markers, but also play a determining pathogenetic role in APS and exert their effects through the activation of cells and coagulation factors and inflammatory mediators for the materialization of the thromboinflammatory pathogenetic mechanism. Cellular activation in APS necessarily involves the interaction of aPLs with target receptors on the cell membrane, capable of triggering the signal transduction pathway(s). This interaction occurs at specific microdomains of the cell plasma membrane called lipid rafts. In this review, we focus on the key role of lipid rafts as signaling platforms in the pathogenesis of APS, and propose this pathogenetic step as a strategic target of new therapies in order to improve classical anti-thrombotic approaches with "new" immunomodulatory drugs.

CCL3 in the bone marrow microenvironment causes bone loss and bone marrow adiposity in aged mice

The central physiological role of the bone marrow renders bone marrow stromal cells (BMSCs) particularly sensitive to aging. With bone aging, BMSCs acquire a differentiation potential bias in favor of adipogenesis over osteogenesis, and the underlying molecular mechanisms remain unclear. Herein, we investigated the factors underlying age-related changes in the bone marrow and their roles in BMSCs' differentiation. Antibody array revealed that CC chemokine ligand 3 (CCL3) accumulation occurred in the serum of naturally aged mice along with bone aging phenotypes, including bone loss, bone marrow adiposity, and imbalanced BMSC differentiation. In vivo Ccl3 deletion could rescue these phenotypes in aged mice. CCL3 improved the adipogenic differentiation potential of BMSCs, with a positive feedback loop between CCL3 and C/EBPα. CCL3 activated C/EBPα expression via STAT3, while C/EBPα activated CCL3 expression through direct promoter binding, facilitated by DNA hypomethylation. Moreover, CCL3 inhibited BMSCs' osteogenic differentiation potential by blocking β-catenin activity mediated by ERK-activated Dickkopf-related protein 1 upregulation. Blocking CCL3 in vivo via neutralizing antibodies ameliorated trabecular bone loss and bone marrow adiposity in aged mice. This study provides insights regarding age-related bone loss and bone marrow adiposity pathogenesis and lays a foundation for the identification of new targets for senile osteoporosis treatment.

A Causal-Pathway Phenotype of Chronic Fatigue Syndrome due to Hemodialysis in Patients with End-Stage Renal Disease

BACKGROUND

End-stage renal disease (ESRD) is associated with fatigue and physiosomatic symptoms.

OBJECTIVE

The objective of this study is to delineate the associations between severity of fatigue and physio-somatic symptoms and glomerular filtration rate, inflammatory biomarkers, and Wnt/cateninpathway proteins.

METHODS

The Wnt-pathway related proteins β-catenin, Dickkopf-related protein 1 (DKK1), R-spondin- 1, and sclerostin were measured by ELISA technique in 60 ESRD patients and 30 controls. The Fibromyalgia and Chronic Fatigue Syndrome (FF) Rating Scale was used to assess the severity of FF symptoms.

RESULTS

ESRD is characterized by a significant increase in the total FF score, muscle tension, fatigue, sadness, sleep disorders, gastro-intestinal (GI) symptoms, and a flu-like malaise. The total-FF score was significantly correlated with serum levels of urea, creatinine, and copper (positively), and β-catenin, eGFR, hemoglobin, albumin, and zinc (inversely). The total-FF score was associated with the number of total dialysis and weekly dialysis sessions, and these dialysis characteristics were more important in predicting FF scores than eGFR measurements. Partial Least Squares analysis showed that the FF score comprised two factors that are differently associated with biomarkers: a) 43.0% of the variance in fatigue, GI symptoms, muscle tension, sadness, and insomnia is explained by hemoglobin, albumin, zinc, β-catenin, and R-spondin-1; and b) 22.3% of the variance in irritability, concentration and memory impairments by increased copper and cations/chloride ratio, and male sex.

CONCLUSION

ESRD patients show high levels of fatigue and physio-somatic symptoms associated with hemodialysis and mediated by dialysis-induced changes in inflammatory pathways, the Wnt/catenin pathway, and copper.

Microglial Expression of the Wnt Signaling Modulator DKK2 Differs between Human Alzheimer's Disease Brains and Mouse Neurodegeneration Models

Wnt signaling is crucial for synapse and cognitive function. Indeed, deficient Wnt signaling is causally related to increased expression of DKK1, an endogenous negative Wnt regulator, and synapse loss, both of which likely contribute to cognitive decline in Alzheimer's disease (AD). Increasingly, AD research efforts have probed the neuroinflammatory role of microglia, the resident immune cells of the CNS, which have furthermore been shown to be modulated by Wnt signaling. The DKK1 homolog DKK2 has been previously identified as an activated response and/or disease-associated microglia (DAM/ARM) gene in a mouse model of AD. Here, we performed a detailed analysis of DKK2 in mouse models of neurodegeneration, and in human AD brain. In APP/PS1 and APP^NL-G-F AD mouse model brains as well as in SOD1^G93A ALS mouse model spinal cords, but not in control littermates, we demonstrated significant microgliosis and microglial Dkk2 mRNA upregulation in a disease-stage-dependent manner. In the AD models, these DAM/ARM Dkk2⁺ microglia preferentially accumulated close to βAmyloid plaques. Furthermore, recombinant DKK2 treatment of rat hippocampal primary neurons blocked WNT7a-induced dendritic spine and synapse formation, indicative of an anti-synaptic effect similar to that of DKK1. In stark contrast, no such microglial DKK2 upregulation was detected in the postmortem human frontal cortex from individuals diagnosed with AD or pathologic aging. In summary, the difference in microglial expression of the DAM/ARM gene DKK2 between mouse models and human AD brain highlights the increasingly recognized limitations of using mouse models to recapitulate facets of human neurodegenerative disease.

Differentiation of hPSCs to Study PRC2 Role in Cell-Fate Specification and Neurodevelopment

Several studies highlighted the importance of the polycomb repressive complex 2 (PRC2) already at the beginning of development. Although the crucial function of PRC2 in regulating lineage commitment and cell-fate specification has been well-established, the in vitro study of the exact mechanisms for which H3K27me3 is indispensable for proper differentiation is still challenging. In this chapter, we report a well-established and reproducible differentiation protocol to generate striatal medium spiny neurons as a tool to explore PRC2 role in brain development.

Wnt signaling and the regulation of pluripotency

The role of Wnt signaling in stem cells has been mired in seemingly contradictory findings. On one hand, Wnt has been heralded as a self-renewal factor. On the other hand, Wnt's association with differentiation and lineage commitment is indisputable. This apparent contradiction is particularly evident in pluripotent stem cells, where Wnt promotes self-renewal as well as differentiation. To resolve this discrepancy one must delve into fundamental principles of pluripotency and gain an appreciation for the concept of pluripotency states, which exist in a continuum with intermediate metastable states, some of which have been stabilized in vitro. Wnt signaling is a critical regulator of transitions between pluripotent states. Here, we will discuss Wnt's roles in maintaining pluripotency, promoting differentiation, as well as stimulating reprogramming of somatic cells to an induced pluripotent state.

The role of Wnt signaling in Xenopus neural induction

Development of the central nervous system in amphibians has called attention from scientists for over a century. Interested in the matter of embryonic inductions, Hans Spemann and Hilde Mangold found out that the dorsal blastopore lip of the salamander's embryo has organizer properties. Such an ectopic graft could induce structures in the host embryo, including a neural tube overlying the notochord of a perfect secondary body axis. A couple of decades later, the frog Xenopus laevis emerged as an excellent embryological experimental model and seminal concepts involving embryonic inductions began to be revealed. The so-called primary induction is, in fact, a composition of signaling and inductive events that are triggered as soon as fertilization takes place. In this regard, since early 1990s an intricate network of signaling pathways has been built. The Wnt pathway, which began to be uncovered in cancer biology studies, is crucial during the establishment of two signaling centers in Xenopus embryogenesis: Nieuwkoop center and the blastula chordin noggin expression center (BCNE). Here we will discuss the historical events that led to the discovery of those centers, as well as the molecular mechanisms by which they operate. This chapter highlights the cooperation of both signaling centers with potential to be further explored in the future. We aim to address the essential morphological transformation during gastrulation and neurulation as well as the role of Wnt signaling in patterning the organizer and the neural plate.

The Molecular Mechanism of Natural Products Activating Wnt/β-Catenin Signaling Pathway for Improving Hair Loss

Hair loss, or alopecia, is a dermatological disorder that causes psychological stress and poor quality of life. Drug-based therapeutics such as finasteride and minoxidil have been clinically used to treat hair loss, but they have limitations due to their several side effects in patients. To solve this problem, there has been meaningful progress in elucidating the molecular mechanisms of hair growth and finding novel targets to develop therapeutics to treat it. Among various signaling pathways, Wnt/β-catenin plays an essential role in hair follicle development, the hair cycle, and regeneration. Thus, much research has demonstrated that various natural products worldwide promote hair growth by stimulating Wnt/β-catenin signaling. This review discusses the functional role of the Wnt/β-catenin pathway and its related signaling molecules. We also review the molecular mechanism of the natural products or compounds that activate Wnt/β-catenin signaling and provide insights into developing therapeutics or cosmeceuticals that treat hair loss.

Regulatory role of miRNAs in Wnt signaling pathway linked with cardiovascular diseases

MicroRNAs (miRNAs) are discovered in science about 23 years ago. These are short, a series of non-coding, single-stranded and evolutionary conserved RNA molecules found in eukaryotic cells. It involved post-transcriptional fine-tune protein expression and repressing the target of mRNA in different biological processes. These miRNAs binds with the 3'-UTR region of specific mRNAs to phosphorylate the mRNA degradation and inhibit the translation process in various tissues. Therefore, aberrant expression in miRNAs induces numerous cardiovascular diseases and developmental defects. Subsequently, the miRNAs and Wnt singling pathway are regulating a cellular process in cardiac development and regeneration, maintain the homeostasis and associated heart diseases. In Wnt signaling pathway majority of the signaling components are expressed and regulated by miRNAs, whereas the inhibition or dysfunction of the Wnt signaling pathway induces cardiovascular diseases. Moreover, inadequate studies about the important role of miRNAs in heart development and diseases through Wnt signaling pathway has been exist still now. For this reason in present review we summarize and update the involvement of miRNAs and the role of Wnt signaling in cardiovascular diseases. We have discussed the mechanism of miRNA functions which regulates the Wnt components in cellular signaling pathway. The fundamental understanding of Wnt signaling regulation and mechanisms of miRNAs is quite essential for study of heart development and related diseases. This approach definitely enlighten the future research to provide a new strategy for formulation of novel therapeutic approaches against cardiovascular diseases.

The Hair Growth-Promoting Effect of Gardenia florida Fruit Extract and Its Molecular Regulation

As a herbal medicine, the extract from the fruits of Gardenia florida has been widely used for its antioxidative, hypoglycemic, and anti-inflammatory properties. However, whether G. florida fruit extract (GFFE) regulates hair growth has been rarely studied. This study was the first application of GFFE on hair growth both in vitro (human dermal papilla cells, hDPCs) and in vivo (C57BL/6 mice). The effects of GFFE on cell proliferation and hair growth-associated gene expression in hDPCs were examined. Moreover, GFFE was applied topically on the hair-shaved skin of male C57BL/6 mice, the hair length was measured, and the skin histological profile was investigated. GFFE promoted the proliferation of hDPCs and significantly stimulated hair growth-promoting genes, including vascular endothelial growth factor (VEGF) and Wnt/β-catenin signals, but suppressed the expression of the hair loss-related gene transforming growth factor-β1 (TGF-β). Furthermore, GFFE treatment resulted in a significant increase in the number, size, and depth of cultured hair follicles and stimulated the growth of hair with local effects in mice. In summary, the results provided the preclinical data to support the much potential use of the natural product GFFE as a promising agent for hair growth.

Antiosteoporosis and bone protective effect of nimbolide in steroid-induced osteoporosis rats

BACKGROUND

Osteoporosis is a metabolic, hereditary, progressive disease characterized by unusual bone production across the skeleton and a loss the bone tissue microstructure and mass. In this experimental study, we scrutinized the antiosteoporosis effect of nimbolide against glucocorticoid (GCs) induced osteoporosis in rats.

METHODS

Swiss albino female rats were employed for the current experiment study and the rats were divided into different groups. Dexamethasone (0.1 mg/kg/day) was used for induction the osteoporosis and the rats were received the different doses of nimbolide (2.5, 5, and 7.5 mg/kg) for the estimation of bone protective effects. The body weight was estimated (initially and finally). Hormones, bone metabolic markers, bone turnover markers, bone structure, biomechanical, histomorphometric dynamic, biochemical markers, and histomorphometric static parameters were analyzed.

RESULTS

The body weight of GCs group rats considerably suppressed and nimbolide treatment remarkably improved the body weight. Nimbolide treated group exhibited the enhancement of bone metabolic, bone structure markers, and histomophometric dynamic markers, which was suppressed during the GCs-induced osteoporosis. GCs-induced osteoporosis rats exhibited the enhancement of procollagen type 1 C-terminal propeptide (P1CP), carboxy-terminal crosslinked telopeptide of type 1 collagen (CTX-1), Dickkopf-1 (DKK1), tartrate-resistant acid phosphatase 5b (TRACP 5b), and suppressed the level of bone alkaline phosphatase (BAP), which was reversed by the nimbolide treatment. Nimbolide treatment remarkably improved the level of estradiol and suppressed the level of parathyroid hormone (PTH), which was altered during the osteoporosis. Nimbolide treatment significantly (p < 0.001) improved the level of calcium, magnesium, and phosphorus in the serum and bone tissue. Nimbolide treatment also altered the level of bone metabolic markers and suppressed the level of inflammatory cytokines.

CONCLUSION

Based on the findings, we may conclude that nimbolide has antiosteoporosis properties via balancing the bone mass and improving vitamin and hormone levels.

The RSPO-LGR4/5-ZNRF3/RNF43 module in liver homeostasis, regeneration, and disease

WNT/β-catenin signaling plays pivotal roles during liver development, homeostasis, and regeneration. Likewise, its deregulation disturbs metabolic liver zonation and is responsible for the development of a large number of hepatic tumors. Liver fibrosis, which has become a major health burden for society and a hallmark of NASH, can also be promoted by WNT/β-catenin signaling. Upstream regulatory mechanisms controlling hepatic WNT/β-catenin activity may constitute targets for the development of novel therapies addressing these life-threatening conditions. The R-spondin (RSPO)-leucine-rich repeat-containing G protein-coupled receptor (LGR) 4/5-zinc and ring finger (ZNRF) 3/ring finger 43 (RNF43) module is fine-tuning WNT/β-catenin signaling in several tissues and is essential for hepatic WNT/β-catenin activity. In this review article, we recapitulate the role of the RSPO-LGR4/5-ZNRF3/RNF43 module during liver development, homeostasis, metabolic zonation, regeneration, and disease. We further discuss the controversy around LGR5 as a liver stem cell marker.

Combined targeting of pathways regulating synaptic formation and autophagy attenuates Alzheimer’s disease pathology in mice

All drug trials completed to date have fallen short of meeting the clinical endpoint of significantly slowing cognitive decline in Alzheimer’s disease (AD) patients. In this study, we repurposed two FDA-approved drugs, Fasudil and Lonafarnib, targeting synaptic formation (i.e., Wnt signaling) and cellular clearance (i.e., autophagic) pathways respectively, to test their therapeutic potential for attenuating AD-related pathology. We characterized our 3xTg AD mouse colony to select timepoints for separate and combinatorial treatment of both drugs while collecting cerebrospinal fluid (CSF) using an optimized microdialysis method. We found that treatment with Fasudil reduced Aβ at early and later stages of AD, whereas administration of Lonafarnib had no effect on Aβ, but did reduce tau, at early stages of the disease. Induction of autophagy led to increased size of amyloid plaques when administered at late phases of the disease. We show that combinatorial treatment with both drugs was effective at reducing intraneuronal Aβ and led to improved cognitive performance in mice. These findings lend support to regulating Wnt and autophagic pathways in order to attenuate AD-related pathology.

Crystallographic mining of ASK1 regulators to unravel the intricate PPI interfaces for the discovery of small molecule

Protein seldom performs biological activities in isolation. Understanding the protein–protein interactions’ physical rewiring in response to pathological conditions or pathogen infection can help advance our comprehension of disease etiology, progression, and pathogenesis, which allow us to explore the alternate route to control the regulation of key target interactions, timely and effectively. Nonalcoholic steatohepatitis (NASH) is now a global public health problem exacerbated due to the lack of appropriate treatments. The most advanced anti-NASH lead compound (selonsertib) is withdrawn, though it is able to inhibit its target Apoptosis signal-regulating kinase 1 (ASK1) completely, indicating the necessity to explore alternate routes rather than complete inhibition. Understanding the interaction fingerprints of endogenous regulators at the molecular level that underpin disease formation and progression may spur the rationale of designing therapeutic strategies. Based on our analysis and thorough literature survey of the various key regulators and PTMs, the current review emphasizes PPI-based drug discovery’s relevance for NASH conditions. The lack of structural detail (interface sites) of ASK1 and its regulators makes it challenging to characterize the PPI interfaces. This review summarizes key regulators interaction fingerprinting of ASK1, which can be explored further to restore the homeostasis from its hyperactive states for therapeutics intervention against NASH.

Di-(2-ethylhexyl) phthalate exposure links to inflammation and low bone mass in premenopausal and postmenopausal females: Evidence from ovariectomized mice and humans

OBJECTIVE

Phthalates induce inflammation and are ubiquitously used in daily life. We aim to study the impact of di-(2-ethylhexyl) phthalate (DEHP) exposure on inflammation and osteoporosis in premenopausal and postmenopausal females.

METHODS

Female 8-week-old C57BL/6JNarl mice received an ovariectomy (OVX) or a sham operation and were fed with DEHP or vehicle by oral gavage for 4 or 8 weeks. Their femurs were isolated for micro-computed tomography, and their serum was collected for inflammatory cytokine assays. Correlations between urinary phthalate metabolites and the lumbar spine bone mineral density (BMD) in premenopausal and postmenopausal volunteers were performed.

RESULTS

Among the OVX mice treated for 4 weeks, significant lower bone volume, bone volume/tissue volume, and trabecular number but significant higher trabecular bone pattern factor and structure model index were identified in the mice treated with DEHP than with vehicle. The OVX mice treated with DEHP for 4 weeks had significantly higher serum interleukin (IL)-1β, IL-10, IL-17A, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and Dickkopf-1 levels than those treated with vehicle. The sham mice treated with DEHP for 8 weeks showed an impaired femur trabecular microstructure and had significantly higher serum IL-1β, IL-6, IL-10, IL-17A, IFN-γ, and TNF-α than those treated with vehicle. DEHP metabolites were inversely correlated with the BMD of premenopausal women and the T-score of postmenopausal women.

CONCLUSION

DEHP treatment in OVX and sham mice results in osteoporosis and impairs the microstructure of the femur trabecula through inflammation. Phthalate exposure negatively affects the bone mass in both premenopausal and postmenopausal women. Thus, long-term avoidance is suggested.

WNT/β-catenin Pathway: a Possible Link Between Hypertension and Alzheimer's Disease

PURPOSE OF REVIEW

Recent research has shown that older people with high blood pressure (BP), or hypertension, are more likely to have biomarkers of Alzheimer's disease (AD). Essential hypertension represents the most common cardiovascular disease worldwide and is thought to be responsible for about 13% of all deaths. People with essential hypertension who regularly take prescribed BP medications are half as likely to develop AD as those who do not take them. What then is the connection?

RECENT FINDINGS

We know that high BP can damage small blood vessels in the brain, affecting those parts that are responsible for memory and thinking. However, the link between AD and hypertension remains unclear. Recent advances in the field of molecular and cellular biology have revealed a downregulation of the canonical WNT/β-catenin pathway in both hypertension and AD. In AD, the glutamate transport function is decreased, a decrease that is associated with a loss of synapse and neuronal death. β-catenin signaling appears to act as a major regulator of glutamate transporters (EAAT and GS) expression and can be harnessed to remove excess glutamate in AD. This review focuses on the possible link between hypertension and AD through the decreased WNT/β-catenin which interacts with the glutamatergic pathway.

Differential Protein Expression of the Marginal Transitional Zone in Foals with Osteochondrosis

The marginal transitional zone is peripherally located within the diarthrodial joint, and represents the interface of articular cartilage, periosteum, and the fibrous joint capsule. The purpose of this study is to characterize the protein expression of matrix and molecular regulators in the marginal transitional zone of foals having osteochondrosis (OC) compared to normal foals. Several families of proteins with known roles in cartilage and bone development are investigated, including matrix molecules, Wnt signaling, apoptotic factors and paracrine cell signaling molecules. Our results demonstrate differential protein expression in the marginal transitional zone from the lateral femoral trochlear ridge of foals affected by osteochondrosis. Alterations in protein expression of OC-affected foals mainly involve components of extracellular matrix homeostasis and canonical Wnt signaling. Matrix expression of collagen type IIB and lubricin are decreased and matrix metalloproteinase-3 expression is increased in OC-affected marginal transitional zone samples. Canonical Wnt signaling is inhibited in OC-affected marginal transitional zone samples, based on increased Dickkopf-1 and decreased β-catenin protein expression. Most apoptotic and paracrine signaling proteins are not altered in OC-affected marginal transitional zone samples.

Chondroitin Sulfates Control Invasiveness of the Basal-Like Breast Cancer Cell Line MDA-MB-231 Through ROR1

Extracellular and cell surface chondroitin sulfates (CSs) regulate cancer cell properties, including proliferation and invasion. Thus, it is necessary to understand the mechanisms underlying their roles in cancer. Although we have shown that CS has an inherent ability to enhance the invasive activity of the human triple-negative breast cancer cell line MDA-MB-231, its molecular mechanism remains elusive. Here, we focused on receptor tyrosine kinase-like orphan receptor 1 (ROR1) and dickkopf WNT signaling pathway inhibitor 1 (DKK1). MDA-MB-231 cells express high levels of ROR1; their invasive potential depends on ROR1 signaling. Although accumulating evidence has demonstrated that ROR1 is associated with aggressive breast-cancer phenotypes, the whole picture of its biological function remains poorly understood. In this study, we examined whether CS controls ROR1 function. Surface plasmon resonance analysis indicated that CSs were bound to ROR1 in the presence of WNT5A. The invasive activity of MDA-MB-231 cells enhanced by CSs was completely suppressed by ROR1 knockdown. In addition, knockdown of the CS biosynthetic enzymes CHST11 and CHST15 inhibited invasive activity, even in the presence of ROR1. These results suggest that CS is required to induce an ROR1-dependent, aggressive MDA-MB-231 phenotype. ROR1 signaling in MDA-MB-231 cells activated c-Jun N-terminal kinase (JNK), leading to increased invasive potential; moreover, exogenous CSs activated JNK. MDA-MB-231 cells express DKK1, a tumor suppressor factor that binds to CS, at high levels. Knockdown of DKK1 enhanced CS-stimulated tumor invasion activity of MDA-MB-231 cells, suggesting that DKK1 sequesters CS to block ROR1/JNK signaling. These results showed that CSs promotes cancer aggressiveness through the ROR1−JNK axis in MDA-MB-231 cells.

Anti-β2-GPI Antibodies Induce Endothelial Cell Expression of Tissue Factor by LRP6 Signal Transduction Pathway Involving Lipid Rafts

In this study we analyzed whether anti-β2-GPI antibodies from patients with APS induce the endothelial cell expression of Tissue Factor (TF) by a LRP6 signal transduction pathway involving lipid rafts. HUVEC were stimulated with affinity purified anti-β2-GPI antibodies. Both LRP6 and β-catenin phosphorylation, as well as TF expression, were evaluated by western blot. Results demonstrated that triggering with affinity purified anti-β2-GPI antibodies induced LRP6 phosphorylation with consequent β-catenin activation, leading to TF expression on the cell surface. Interestingly, the lipid rafts affecting agent methyl-β-cyclodextrin as well as the LRP6 inhibitor Dickkopf 1 (DKK1) partially reduced the anti-β2-GPI antibodies effect, indicating that the anti-β2-GPI effects on TF expression may depend on a signalling transduction pathway involving both lipid rafts and LRP6. An interaction between β2-GPI, LRP6 and PAR-2 within these microdomains was demonstrated by gradient fractionation and coimmunoprecipitation experiments. Thus, anti-β2-GPI antibodies react with their target antigen likely associated to LRP6 and PAR-2 within plasma membrane lipid rafts of the endothelial cell. Anti-β2-GPI binding triggers β-catenin phosphorylation, leading to a procoagulant phenotype characterized by TF expression. These findings deal with a novel signal transduction pathway which provides new insight in the APS pathogenesis, improving the knowledge of valuable therapeutic target(s).

miR‑148a‑3p facilitates osteogenic differentiation of fibroblasts in ankylosing spondylitis by activating the Wnt pathway and targeting DKK1

Ankylosing spondylitis (AS) is a chronic inflammatory form of arthritis. MicroRNAs (miRNAs) have been identified to serve as therapeutic targets in various inflammatory diseases. The aim of the present study was to determine the functional mechanism of miR-148a-3p on AS. Specimens were collected from AS patients and non-AS patients. Fibroblasts were delivered with the aid of miR-148a-3p inhibitor. Cell staining was performed to observe the morphological changes, calcified nodules, and mineralization degree. The binding sites of miR-148a-3p and DKK1 were predicted on the Starbase website and subsequently verified by means of dual-luciferase reporter assay. AS fibroblasts with silenced miR-148a-3p were transfected with si-DKK1. Levels of RUNX2 and Osteocalcin, DKK1 and Wnt1 protein and phosphorylation level of β-catenin were detected by means of western blot analysis. Results of the present study denoted that AS upregulated miR-148a-3p in fibroblasts to exacerbate osteogenic differentiation, resulting in increased calcified nodules and mineralization degree. Silencing miR-148a-3p could reverse the upregulation of RUNX2 and Osteocalcin in AS fibroblasts and reduce the calcified nodules and mineralization degree. miR-148a-3p targeted DKK1. DKK1 knockdown averted the effect of silencing miR-148a-3p in AS fibroblasts. In addition, silencing miR-148a-3p reversed the upregulation of Wnt1 and β-catenin proteins in AS fibroblasts. To conclude, miR-148a-3p exacerbated the osteogenic differentiation of AS fibroblasts by inhibiting DKK1 expression and activating the Wnt pathway.

Intestinal Wnt in the transition from physiology to oncology

Adult stem cells are necessary for self-renewal tissues and regeneration after damage. Especially in the intestine, which self-renews every few days, they play a key role in tissue homeostasis. Therefore, complex regulatory mechanisms are needed to prevent hyperproliferation, which can lead in the worst case to carcinogenesis or under-activation of stem cells, which can result in dysfunctional epithelial. One main regulatory signaling pathway is the Wnt/β-catenin signaling pathway. It is a highly conserved pathway, with β-catenin, a transcription factor, as target protein. Translocation of β-catenin from cytoplasm to nucleus activates the transcription of numerous genes involved in regulating stem cell pluripo-tency, proliferation, cell differentiation and regulation of cell death. This review presents a brief overview of the Wnt/β-catenin signaling pathway, the regulatory mechanism of this pathway and its role in intestinal homeostasis. Additionally, this review highlights the molecular mechanisms and the histomorphological features of Wnt hyperactivation. Furthermore, the central role of the Wnt signaling pathway in intestinal carcinogenesis as well as its clinical relevance in colorectal carcinoma are discussed.

The Wnt Pathway: From Signaling Mechanisms to Synthetic Modulators

The Wnt pathway is central to a host of developmental and disease-related processes. The remarkable conservation of this intercellular signaling cascade throughout metazoan lineages indicates that it coevolved with multicellularity to regulate the generation and spatial arrangement of distinct cell types. By regulating cell fate specification, mitotic activity, and cell polarity, Wnt signaling orchestrates development and tissue homeostasis, and its dysregulation is implicated in developmental defects, cancer, and degenerative disorders. We review advances in our understanding of this key pathway, from Wnt protein production and secretion to relay of the signal in the cytoplasm of the receiving cell. We discuss the evolutionary history of this pathway as well as endogenous and synthetic modulators of its activity. Finally, we highlight remaining gaps in our knowledge of Wnt signal transduction and avenues for future research. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Circulating cytokines present in multiple myeloma patients inhibit the osteoblastic differentiation of adipose stem cells

Myeloma is characterized by bone lesions, which are related to both an increased osteoclast activity and a defect in the differentiation of medullary mesenchymal stem cells (MSCs) into osteoblasts. Outside the medullary environment, adipocyte-derived MSCs (ASCs) could represent a source of functional osteoblasts. However, we recently found a defect in the osteoblastic differentiation of ASCs from myeloma patients (MM-ASCs). We examined the effects of plasma from myeloma patients at diagnosis (MM-plasmas) and in complete remission (CR-plasmas) and from healthy donors on the osteoblastic differentiation of healthy donor-derived ASCs (HD-ASCs). Osteoblastogenesis in HD-ASCs was suppressed by MM-plasmas. Seven cytokines (ANG1, ENA-78, EGF, PDGF-AA/AB/BB, and TARC) were increased in MM-plasmas and separately inhibited the osteoblastic differentiation of HD-ASCs. Comparison of MM-ASCs and HD-ASCs by RNA sequencing showed that two master genes characterizing adipocyte differentiation, CD36 and PPARγ, were upregulated in MM-ASCs as compared to HD-ASCs. Finally, we demonstrated a significant increase in CD36 and PPARγ expression in HD-ASCs in the presence of MM-plasmas or the seven cytokines individually, similarly as in MM-ASCs. We conclude that specific cytokines in MM-plasmas, besides the well-known DKK1, inhibit the osteoblastic differentiation of MM- and HD-ASCs with a skewing towards adipocyte differentiation.

Wnt Pathway Extracellular Components and Their Essential Roles in Bone Homeostasis

The Wnt pathway is involved in several processes essential for bone development and homeostasis. For proper functioning, the Wnt pathway is tightly regulated by numerous extracellular elements that act by both activating and inhibiting the pathway at different moments. This review aims to describe, summarize and update the findings regarding the extracellular modulators of the Wnt pathway, including co-receptors, ligands and inhibitors, in relation to bone homeostasis, with an emphasis on the animal models generated, the diseases associated with each gene and the bone processes in which each member is involved. The precise knowledge of all these elements will help us to identify possible targets that can be used as a therapeutic target for the treatment of bone diseases such as osteoporosis.

MicroRNA-217: a therapeutic and diagnostic tumor marker

INTRODUCTION

Cancer as one of the most common causes of death has always been one of the major health challenges globally. Since, the identification of tumors in the early tumor stages can significantly reduce mortality rates; it is required to introduce novel early detection tumor markers. MicroRNAs (miRNAs) have pivotal roles in regulation of cell proliferation, migration, apoptosis, and tumor progression. Moreover, due to the higher stability of miRNAs than mRNAs in body fluids, they can be considered as non-invasive diagnostic or prognostic markers in cancer patients.

AREAS COVERED

In the present review we have summarized the role of miR-217 during tumor progressions. The miR-217 functions were categorized based on its target molecular mechanisms and signaling pathways.

EXPERT OPINION

It was observed that miR-217 mainly exerts its function by regulation of the transcription factors during tumor progressions. The WNT, MAPK, and PI3K/AKT signaling pathways were also important molecular targets of miR-217 in different cancers. The present review clarifies the molecular biology of miR-217 and paves the way of introducing miR-217 as a non-invasive diagnostic marker and therapeutic target in cancer therapy.