Dickkopf1 fuels inflammatory cytokine responses

Bone-derived factors mediate crosstalk between skeletal and extra-skeletal organs

Bone has long been acknowledged as a fundamental structural entity that provides support and protection to the body's organs. However, emerging research indicates that bone plays a crucial role in the regulation of systemic metabolism. This is achieved through the secretion of a variety of hormones, cytokines, metal ions, extracellular vesicles, and other proteins/peptides, collectively referred to as bone-derived factors (BDFs). BDFs act as a medium through which bones can exert targeted regulatory functions upon various organs, thereby underscoring the profound and concrete implications of bone in human physiology. Nevertheless, there remains a pressing need for further investigations to elucidate the underlying mechanisms that inform the effects of bone on other body systems. This review aims to summarize the current findings related to the roles of these significant modulators across different organs and metabolic contexts by regulating critical genes and signaling pathways in vivo. It also addresses their involvement in the pathogenesis of various diseases affecting the musculoskeletal system, circulatory system, glucose and lipid metabolism, central nervous system, urinary system, and reproductive system. The insights gained from this review may contribute to the development of innovative therapeutic strategies through a focused approach to bone secretomes. Continued research into BDFs is expected to enhance our understanding of bone as a multifunctional organ with diverse regulatory roles in human health.

Plasma Dickkopf-1 Levels Are Associated with Chronic Kidney Disease

BACKGROUND

Wnt/β-catenin signaling is important in the development and repair of the kidney. Dickkopf-1 (DKK-1) is characterized as an inhibitor of the Wnt/β-catenin signaling pathway.

PURPOSE

We examined the relationship between plasma DKK-1 levels and the risk of chronic kidney disease (CKD).

METHODS

In this cross-sectional study, patients without known diabetes mellitus who were admitted for coronary angiography due to angina were enrolled. Fasting blood samples were collected at a predetermined outpatient visit.

RESULTS

Among 373 enrolled patients, 62 (16.6%) were in the CKD group, and 311 (83.4%) were in the nonCKD group. Plasma DKK-1 levels were significantly higher in the CKD group than in the nonCKD group (697.2 ± 174.7 vs. 589.0 ± 193.3 pg/mL; p < 0.001). Plasma DKK-1 levels were inversely correlated with the eGFR (Pearson's correlation coefficient = -0.265; p < 0.001). On the basis of multivariable logistic regression analyses, patients in the highest DKK-1 quartile had a significantly greater risk of CKD (OR = 4.188; 95% CI: 1.564, 11.212; p = 0.004) than did those in the lowest DKK-1 quartile.

CONCLUSIONS

Plasma DKK-1 levels are associated with the risk of CKD in patients with angina. Further studies investigating the underlying mechanisms involved in the relationship between DKK-1 and CKD are warranted.

Targeting RBM39 suppresses tumor growth and sensitizes osteosarcoma cells to cisplatin

Osteosarcoma is one of the most common malignant primary bone tumors and lacks effective therapeutic targets. Recent studies have reported that RNA binding proteins (RBPs) could serve as promising therapeutic targets for cancers, as their critical roles in transcriptional regulation and RNA splicing. Nevertheless, the potential of pharmacologically inhibiting RBPs as a therapeutic strategy for patients with osteosarcoma remains unclear. In this study, we identified the RNA-binding protein RBM39 as a promising therapeutic target for osteosarcoma. RBM39 is essential for cell viability, and a higher expression of RBM39 was associated with poor prognosis in osteosarcoma. Mechanistically, RBM39 served as a coactivator of c-Jun to transcriptionally upregulate DKK1, leading to the activation of the GSK3β-NF-κB pathway. Importantly, our results reveal that the pharmacological depletion of RBM39 by using the anti-cancer aryl sulfonamide (E7820), a drug known for its oral bioavailability and safe administration, effectively represses osteosarcoma growth and sensitizes osteosarcoma cells to cisplatin treatment both in vitro and in vivo. Our findings unveil the crucial role of RBM39 in modulating tumor growth and cisplatin sensitivity in osteosarcoma cells, suggesting that the combination of aryl sulfonamides with cisplatin may benefit patients with osteosarcoma.

Antisense mediated blockade of Dickkopf 1 attenuates tumor survival, metastases and bone damage in experimental osteosarcoma

Osteosarcoma (OS) is the most common primary bone malignancy. The canonical Wnt inhibitor Dickkopf-1 (Dkk-1) has been implicated in bone destruction, tumor survival and metastases during OS. We examined the role of Dkk-1 in OS disease progression and explored strategies for targeting its activity. Dkk-1 enhances OS survival by amplifying a non-canonical Wnt pathway that upregulates aldehyde dehydrogenase 1A1. Targeting of Dkk-1 transcription with a vivo morpholino (DkkMo) reduced OS survival and enhanced osteogenic activity of OS in vitro. DkkMo as a single agent slowed tumor expansion, increased tumor necrosis, inhibited metastases and preserved bone in a PDX model of OS. DkkMo also reduced the frequency of dividing tumor cells and reinitiated a regenerative osteogenic phenotype in tumors and stroma while reducing infiltration of inflammatory cells. These findings indicate that DkkMo has the potential to safely target osteosarcoma growth, survival, metastases and bone destruction.

Time-series single-cell transcriptomic profiling of luteal-phase endometrium uncovers dynamic characteristics and its dysregulation in recurrent implantation failures

Understanding human endometrial dynamics in the establishment of endometrial receptivity remains a challenge, which limits early diagnosis and treatment of endometrial-factor infertility. Here, we decode the endometrial dynamics of fertile women across the window of implantation and characterize the endometrial deficiency in women with recurrent implantation failure. A computational model capable of both temporal prediction and pattern discovery is used to analyze single-cell transcriptomic data from over 220,000 endometrial cells. The time-series atlas highlights a two-stage stromal decidualization process and a gradual transitional process of the luminal epithelial cells across the window of implantation. In addition, a time-varying gene set regulating epithelium receptivity is identified, based on which the recurrent implantation failure endometria are stratified into two classes of deficiencies. Further investigation uncovers a hyper-inflammatory microenvironment for the dysfunctional endometrial epithelial cells of recurrent implantation failure. The holistic characterization of the physiological and pathophysiological window of implantation and a computational tool trained on this temporal atlas provide a platform for future therapeutic developments.

Curcumin alleviated dextran sulfate sodium-induced ulcerative colitis via inhibition of the Wnt/β-catenin signaling pathway and regulation of the differentiation of intestinal stem cells

In this study, we investigated the regulatory role of curcumin in the differentiation of intestinal stem cells (ISCs) in dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) model mice and explored whether this effect was mediated by the Wnt/β-catenin signaling pathway. We conducted experiments in DSS-induced UC model mice to observe changes in intestinal morphology through HE staining and detect the expression of key proteins in the Wnt/β-catenin signaling pathway. According to these findings, curcumin was found to have a significant impact on the differentiation of ISCs. These results indicated that curcumin inhibited the Wnt/β-catenin signaling pathway and restored ISC differentiation. The effects of curcumin on the Wnt/β-catenin signaling pathway were further confirmed using Wnt/β-catenin agonists. These findings provide a new perspective for understanding the behavior of ISCs in the context of inflammation and offer new insights into the development of novel therapeutic strategies and drugs for UC.

Circulating DKK1 levels are significantly elevated in obese individuals and are associated with insulin resistance and oxidative stress

Dickkopf-1 (DKK1) is reportedly involved in various biological functions of the human body. However, the relationship between DKK1 and obesity in humans remains unknown. Bioinformatics analysis was performed to investigate the associations between DKK1 and metabolism-related genes and signaling pathways. EHC and OGTT were performed on all individuals. Serum DKK1 concentrations were measured by an ELISA kit. DKK1 expression was measured by qRT-PCR and Western blotting. We found that circulating DKK1 levels in overweight/obese (OW/OB) individuals were significantly elevated and were associated with parameters of glucose/lipid metabolism and IR, including BMI, WHR, fat%, TC, TG, FBG, 2 h-BG, FIns, 2 h-Ins, LDL-C, HbA1c, HOMA-IR, AUCi, AUCg, BAI, and VAI. The circulating DKK1 concentration was not affected by blood glucose or serum insulin levels. Bioinformatics analysis suggested that DKK1 may be associated with glucose/lipid metabolism and oxidative stress. At the cellular level, we found that DKK1 promoted oxidative stress and inhibited insulin signaling. Circulating DKK1 may be a biomarker for obesity and IR.

Enhancing motor functional recovery in spinal cord injury through pharmacological inhibition of Dickkopf-1 with BHQ880 antibody

BACKGROUND

Mounting experimental evidence has underscored the remarkable role played by the Wnt family of proteins in the spinal cord functioning and therapeutic potential in spinal cord injury (SCI). We aim to provide a therapeutic prospect associated with the modulation of canonical Wnt signaling, examining the spatio-temporal expression pattern of Dickkopf-1 (Dkk1) and its neutralization after SCI. We employ an intraparenchymal injection of the clinically validated Dkk1-blocking antibody, BHQ880, to elucidate its effects in SCI.

METHODS

A rat model of contusion SCI was used. Histological analyses were performed, wherein Dkk1 protein was sought, and ELISA analyses were employed for Dkk1 detection in cerebrospinal fluid and serum. To ascertain the BHQ880 therapeutic effect, rats were subjected to SCI and then injected with the antibody in the lesion epicenter 24 hours post-injury (hpi). Subsequent evaluation of motor functional recovery extended up to 56 days post-injury (dpi). qRT-PCR and histological analyses were conducted.

RESULTS

We demonstrate the presence of Dkk1 in the healthy rat spinal cord, with pronounced alterations observed following injury, primarily concentrated in the epicenter regions. Notably, a significative upregulation of Dkk1 was detected at 24 hpi, peaking at 3 dpi and remaining elevated until 42 dpi. Moreover, we revealed that early administration of BHQ880 considerably improved motor functional recovery, promoted preservation of myelinated tissue, and reduced astroglial and microglia/macrophage reactivity. Furthermore, there was a decrease in the acute expression of different inflammatory genes.

CONCLUSIONS

Collectively, our findings highlight the therapeutic potential of BHQ880 treatment in the context of SCI.

A Protective Role of Canonical Wnt/β-Catenin Pathway in Pathogenic Bacteria-Induced Inflammatory Responses

Inflammation is a complex host defensive response against various disease-associated pathogens. A baseline extent of inflammation is supposed to be tightly associated with a sequence of immune-modulated processes, resulting in the protection of the host organism against pathogen invasion; however, as a matter of fact is that an uncontrolled inflammatory cascade is the main factor responsible for the host damage, accordingly suggesting a significant and indispensable involvement of negative feedback mechanism in modulation of inflammation. Evidence accumulated so far has supported a repressive effect of the canonical Wnt/β-catenin pathway on microbial-triggered inflammation via diverse mechanisms, although that consequence is dependent on the cellular context, types of stimuli, and cytokine environment. It is of particular interest and importance to comprehend the precise way in which the Wnt/β-catenin pathway is activated, due to its essential anti-inflammatory properties. It is assumed that an inflammatory milieu is necessary for initiating and activating this signaling, implying that Wnt activity is responsible for shielding tissues from overwhelming inflammation, thus sustaining a balanced physiological condition against bacterial infection. This review gathers the recent efforts to elucidate the mechanistic details through how Wnt/β-catenin signaling modulates anti-inflammatory responses in response to bacterial infection and its interactions with other inflammatory signals, which warrants further study for the development of specific interventions for the treatment of inflammatory diseases. Further clinical trials from different disease settings are required.

Small-molecule CBP/p300 histone acetyltransferase inhibition mobilizes leukocytes from the bone marrow via the endocrine stress response

Mutations of the CBP/p300 histone acetyltransferase (HAT) domain can be linked to leukemic transformation in humans, suggestive of a checkpoint of leukocyte compartment sizes. Here, we examined the impact of reversible inhibition of this domain by the small-molecule A485. We found that A485 triggered acute and transient mobilization of leukocytes from the bone marrow into the blood. Leukocyte mobilization by A485 was equally potent as, but mechanistically distinct from, granulocyte colony-stimulating factor (G-CSF), which allowed for additive neutrophil mobilization when both compounds were combined. These effects were maintained in models of leukopenia and conferred augmented host defenses. Mechanistically, activation of the hypothalamus-pituitary-adrenal gland (HPA) axis by A485 relayed shifts in leukocyte distribution through corticotropin-releasing hormone receptor 1 (CRHR1) and adrenocorticotropic hormone (ACTH), but independently of glucocorticoids. Our findings identify a strategy for rapid expansion of the blood leukocyte compartment via a neuroendocrine loop, with implications for the treatment of human pathologies.