Midkine: A multifaceted driver of atherosclerosis

Targeting the CDK7-MDK axis to suppresses irinotecan resistance in colorectal cancer

AIMS

Colorectal cancer (CRC) remains a major global health issue, with metastatic cases presenting poor prognosis despite advances in chemotherapy and targeted therapy. Irinotecan, a key drug for advanced CRC treatment, faces challenges owing to the development of resistance. This study aimed to understand the mechanisms underlying irinotecan resistance in colorectal cancer.

MAIN METHODS

We created a cell line resistant to irinotecan using HT29 cells. These resistant cells were utilized to investigate the role of the CDK7-MDK axis. We employed bulk RNA sequencing, conducted in vivo experiments with mice, and analyzed patient tissues to examine the effects of the CDK7-MDK axis on the cellular response to irinotecan.

KEY FINDINGS

Our findings revealed that HT29 cells resistant to irinotecan, a crucial colorectal cancer medication, exhibited significant phenotypic and molecular alterations compared to their parental counterparts, including elevated stem cell characteristics and increased levels of cytokines and drug resistance proteins. Notably, CDK7 expression was substantially higher in these resistant cells, and targeting CDK7 effectively decreased their survival and tumor growth, enhancing irinotecan sensitivity. RNA-seq analysis indicated that suppression of CDK7 in irinotecan-resistant HT29 cells significantly reduced Midkine (MDK) expression. Decreased CDK7 and MDK levels, achieved through siRNA and the CDK7 inhibitor THZ1, enhanced the sensitivity of resistant HT29 cells to irinotecan.

SIGNIFICANCE

Our study sheds light on how CDK7 and MDK influence irinotecan resistance in colorectal and highlights the potential of MDK-targeted therapies. We hypothesized that irinotecan sensitivity and overall treatment efficacy would improve by inhibiting MDK. This finding encourages a careful yet proactive investigation of MDK as a therapeutic target to enhance outcomes in colorectal cancer patients.

Elucidation of pericholangitis and periductal fibrosis in cholestatic liver diseases via extracellular vesicles released by polarized biliary epithelial cells

Cholestatic liver diseases causes inflammation and fibrosis around bile ducts. However, the pathological mechanism has not been elucidated. Extracellular vesicles (EVs) are released from both the basolateral and apical sides of polarized biliary epithelial cells. We aimed to investigate the possibility that EVs released from the basolateral sides of biliary epithelial cells by bile acid stimulation induce inflammatory cells and fibrosis around bile ducts, and they may be involved in the pathogenesis of cholestatic liver disease. Human biliary epithelial cells (H69) were grown on cell culture inserts and stimulated with chenodeoxycholic acid + IFN-γ. Human THP-1-derived M1-macrophages, LX-2 cells, and KMST-6 cells were treated with the extracted basolateral EVs, and inflammatory cytokines and fibrosis markers were detected by RT-PCR. Highly expressed proteins from stimulated EVs were identified, and M1-macrophages, LX-2, KMST-6 were treated with these recombinant proteins. Stimulated EVs increased the expression of TNF, IL-1β, and IL-6 in M1-macrophages, TGF-β in LX-2 and KMST-6 compared with the corresponding expression levels in unstimulated EVs. Nucleophosmin, nucleolin, and midkine levels were increased in EVs from stimulated cells compared with protein expression in EVs from unstimulated cells. Leukocyte cell-derived chemotaxin-2 (LECT2) is highly expressed only in EVs from stimulated cells. Stimulation of M1-macrophages with recombinant nucleophosmin, nucleolin, and midkine significantly increased the expression of inflammatory cytokines. Stimulation of LX-2 and KMST-6 with recombinant LECT2 significantly increased the expression of fibrotic markers. These results suggest that basolateral EVs are related to the development of pericholangitis and periductal fibrosis in cholestatic liver diseases.NEW & NOTEWORTHY Our research elucidated that the composition of basolateral EVs from the biliary epithelial cells changed under bile acid exposure and the basolateral EVs contained the novel inflammation-inducing proteins NPM, NCL, and MK and the fibrosis-inducing protein LECT2. We report that these new results are possible to lead to the potential therapeutic target of cholestatic liver diseases in the future.

Evaluation of serum midkine levels and metabolic parameters in patients with hidradenitis suppurativa

The exact pathogenesis of Hidradenitis suppurativa (HS) has not been known yet. Midkine (MK) is a heparin-binding protein that has crucial roles in many processes such as cell proliferation, cell survival, cell migration, anti-apoptotic activity, and also inflammation and angiogenesis. No data exists in the literature on the evaluation of MK in patients with HS. The present study aimed to determine the serum levels of MK and metabolic parameters in patients with HS and to compare them with healthy subjects. Forty-five patients with HS and 45 healthy controls were included. The severity of the disease was assessed with Hurley staging system in the patient group. Levels of MK, C-reactive protein (CRP), lipids, and fasting glucose were measured with the enzyme-linked immunosorbent assay (ELISA) method. MK levels were significantly higher in the patient group (p < 0.05). Moreover, smoking habit, total cholesterol, triglyceride (TG), low-density lipoprotein (LDL) and CRP were significantly higher in the patient group (for all p < 0.05). Correlation analyses revealed that MK value was correlated positively with waist circumference, TG, total cholesterol level and diastolic blood pressure (for all p < 0.05), while negatively correlated with high-density lipoprotein (HDL) level (p = 0.046, r = - 0.219). There was no difference in the MK levels according to the severity of the disease among patients. This is the first preliminary study showing that these patients with HS have higher serum MK levels, which may also be related to autoinflammation, angiogenesis, atherosclerosis and metabolic syndrome risk.

Novel Biomarkers for Atherosclerotic Disease: Advances in Cardiovascular Risk Assessment

Atherosclerosis is a significant health concern with a growing incidence worldwide. It is directly linked to an increased cardiovascular risk and to major adverse cardiovascular events, such as acute coronary syndromes. In this review, we try to assess the potential diagnostic role of biomarkers in the early identification of patients susceptible to the development of atherosclerosis and other adverse cardiovascular events. We have collected publications concerning already established parameters, such as low-density lipoprotein cholesterol (LDL-C), as well as newer markers, e.g., apolipoprotein B (apoB) and the ratio between apoB and apoA. Additionally, given the inflammatory nature of the development of atherosclerosis, high-sensitivity c-reactive protein (hs-CRP) or interleukin-6 (IL-6) are also discussed. Additionally, newer publications on other emerging components linked to atherosclerosis were considered in the context of patient evaluation. Apart from the already in-use markers (e.g., LDL-C), emerging research highlights the potential of newer molecules in optimizing the diagnosis of atherosclerotic disease in earlier stages. After further studies, they might be fully implemented in the screening protocols.

Role of Midkine in Cancer Drug Resistance: Regulators of Its Expression and Its Molecular Targeting

Molecules involved in drug resistance can be targeted for better therapeutic efficacies. Research on midkine (MDK) has escalated in the last few decades, which affirms a positive correlation between disease progression and MDK expression in most cancers and indicates its association with multi-drug resistance in cancer. MDK, a secretory cytokine found in blood, can be exploited as a potent biomarker for the non-invasive detection of drug resistance expressed in various cancers and, thereby, can be targeted. We summarize the current information on the involvement of MDK in drug resistance, and transcriptional regulators of its expression and highlight its potential as a cancer therapeutic target.

Secreted proteins MDK, WFDC2, and CXCL14 as candidate biomarkers for early diagnosis of lung adenocarcinoma

BACKGROUND

Early diagnosis of lung adenocarcinoma (LUAD), one of the most common types of lung cancer, is very important to improve the prognosis of patients. The current methods can't meet the requirements of early diagnosis. There is a pressing need to identify novel diagnostic biomarkers. Secretory proteins are the richest source for biomarker research. This study aimed to identify candidate secretory protein biomarkers for early diagnosis of LUAD by integrated bioinformatics analysis and clinical validation.

METHODS

Differentially expressed genes (DEGs) of GSE31210, gene expression data of early stage of LUAD, were analyzed by GEO2R. Upregulated DEGs predicted to encode secreted proteins were obtained by taking the intersection of the DEGs list with the list of genes encoding secreted proteins predicted by the majority decision-based method (MDSEC). The expressions of the identified secreted proteins in the lung tissues of early-stage LUAD patients were further compared with the healthy control group in mRNA and protein levels by using the UALCAN database (TCGA and CPTAC). The selected proteins expressed in plasma were further validated by using Luminex technology. The diagnostic value of the screened proteins was evaluated by receiver operating characteristic (ROC) analysis. Cell counting kit-8 assay was carried out to investigate the proliferative effects of these screened proteins.

RESULTS

A total of 2183 DEGs, including 1240 downregulated genes and 943 upregulated genes, were identified in the GSE31210. Of the upregulated genes, 199 genes were predicted to encode secreted proteins. After analysis using the UALCAN database, 16 molecules were selected for further clinical validation. Plasma concentrations of three proteins, Midkine (MDK), WAP four-disulfide core domain 2 (WFDC2), and C-X-C motif chemokine ligand 14 (CXCL14), were significantly higher in LUAD patients than in healthy donors. The area under the curve values was 0.944, 0.881, and 0.809 for MDK, WFDC2, and CXCL14, 0.962 when combined them. Overexpression of the three proteins enhanced the proliferation activity of A549 cells.

CONCLUSIONS

MDK, WFDC2, and CXCL14 were identified as candidate diagnostic biomarkers for early-stage LUAD and might also play vital roles in tumorigenesis.

Long noncoding RNA THRIL promotes foam cell formation and inflammation in macrophages

Tumor necrosis factor-α (TNF-α) and heterogenous nuclear ribonucleoprotein L (hnRNPL)-related immunoregulatory lincRNA (THRIL) is a long noncoding RNA (lncRNA) involved in various inflammatory diseases. However, its role in atherosclerosis is not known. In this study, we aimed to investigate the function of THRIL in mediating macrophage inflammation and foam cell formation. The expression of THRIL was quantified in THP-1 macrophages after treatment with oxidized low-density lipoprotein (oxLDL). The effect of THRIL overexpression and knockdown on oxLDL-induced inflammatory responses and lipid accumulation was determined. THRIL-associated protein partners were identified by RNA pull-down and RNA immunoprecipitation assays. We show that THRIL is upregulated in macrophages after oxLDL treatment. Knockdown of THRIL blocks oxLDL-induced expression of interleukin-1β (IL-1β), IL-6, and TNF-α and lipid accumulation. Conversely, ectopic expression of THRIL enhances inflammatory gene expression and lipid deposition in oxLDL-treated macrophages. Moreover, THRIL depletion increases cholesterol efflux from macrophages and the expression of ATP-binding cassette transporter (ABC) A1 and ABCG1. FOXO1 is identified as a protein partner of THRIL and promotes macrophage inflammation and lipid accumulation. Furthermore, overexpression of FOXO1 restores lipid accumulation and inflammatory cytokine production in THRIL-depleted macrophages. In conclusion, our data suggest a model where THRIL interacts with FOXO1 to promote macrophage inflammation and foam cell formation. THRIL may represent a therapeutic target for atherosclerosis.

Small Molecule BRD4 Inhibitors Apabetalone and JQ1 Rescues Endothelial Cells Dysfunction, Protects Monolayer Integrity and Reduces Midkine Expression

NF-κB signaling is a key regulator of inflammation and atherosclerosis. NF-κB cooperates with bromodomain-containing protein 4 (BRD4), a transcriptional and epigenetic regulator, in endothelial inflammation. This study aimed to investigate whether BRD4 inhibition would prevent the proinflammatory response towards TNF-α in endothelial cells. We used TNF-α treatment of human umbilical cord-derived vascular endothelial cells to create an in vitro inflammatory model system. Two small molecule inhibitors of BRD4—namely, RVX208 (Apabetalone), which is in clinical trials for the treatment of atherosclerosis, and JQ1—were used to analyze the effect of BRD4 inhibition on endothelial inflammation and barrier integrity. BRD4 inhibition reduced the expression of proinflammatory markers such as SELE, VCAM-I, and IL6 in endothelial cells and prevented TNF-α-induced endothelial tight junction hyperpermeability. Endothelial inflammation was associated with increased expression of the heparin-binding growth factor midkine. BRD4 inhibition reduced midkine expression and normalized endothelial permeability upon TNF-α treatment. In conclusion, we identified that TNF-α increased midkine expression and compromised tight junction integrity in endothelial cells, which was preventable by pharmacological BRD4 inhibition.

Targeting of midkine alleviates cardiac hypertrophy via attenuation of oxidative stress and autophagy

Midkine levels are related to various diseases, including cardiovascular disease, renal disease and autoimmune disease. The research aimed to investigate the mitigation influence of downregulation of intermediate factors on myocardial hypertrophy induced by angiotensin Ⅱ (Ang), and whether downregulation of midkine could attenuate oxidative stress and autophagy. Induced myocardial hypertrophy of the mice model and treated HL-1 cells with Ang Ⅱ in vitro. The expressions of midkine were increased in the model and HL-1 cells with Ang II treatment. Midkine silence alleviated cardiac hypertrophy induced by Ang II, and inhibited the increases of atrial natriuretic peptide (ANP), Brain natriuretic peptide (BNP) and beta-myosin heavy chain (β-MHC) in the heart of mice. The raises of ANP, BNP and β-MHC in Ang II-induced HL-1 cells were also suppressed after midkine downregulation. Downregulating of midkine inhibited the increases of oxidative stress markers 8-OHdG, superoxide anions and MDA in the heart of mice or in the Ang II-treated HL-1 cells. The raises of LC3B, Atg3, Atg5 and Beclin1 in mice heart and in the Ang II.-induced HL-1 cells were attenuated after midkine silence. These outcomes showed that midkine was upregulated in myocardial hypertrophy mice. Targeting of midkine could alleviate cardiac hypertrophy via attenuation of oxidative stress and autophagy.

Midkine promotes kidney injury in diabetic kidney disease by increasing neutrophil extracellular traps formation

Background

We sought to investigate the role of midkine (MK) on neutrophil extracellular trap formation (NETosis) and diabetic kidney disease (DKD) progression.

Methods

The expression of MK and NETosis in the renal tissue of DKD patients was examined by immunohistochemistry and immunofluorescence, respectively. Neutrophils extracted from mouse bone marrow by gradient centrifugation were treated with MK for this in-vitro study. A mouse diabetes model was induced by a high-fat diet combined with an intraperitoneal injection of streptozocin (STZ). Antisense oligodeoxynucleotide (ODN) for MK inhibition was administered via tail vein injection.

Results

We found that the expression of MK was increased in the kidney tissue of DKD patients. Additionally, a greater number of neutrophils were primed toward NETosis in the kidney tissue of DKD patients, which was manifested by the increased expression of NETosis biomarkers citrullinated histone H3 (H3Cit) and myeloperoxidase (MPO). In vitro, MK treatment concentration-dependently increased neutrophil proliferation (cell counting kit-8). Further, western blot and enzyme-linked immunosorbent assays showed that MK (100 ng/mL) significantly promoted NETosis and the expression of inflammatory factors interleukin (IL)-1 and IL-6 secretion in high-glucose treated neutrophils. In the mouse diabetes model, MK promoted the pathological damage and fibrosis of kidney tissue, as demonstrated by the reversion of the pathological damage and fibrosis by the MK antisense ODN [diabetes mellitus (DM) + MK – ODN] treatment. Additionally, the inhibition of MK reduced the formation of NETs.

Conclusions

MK promotes DKD progression by increasing NETosis.

Novel Biomarkers of Atherosclerotic Vascular Disease-Latest Insights in the Research Field

The atherosclerotic vascular disease is a cardiovascular continuum in which the main role is attributed to atherosclerosis, from its appearance to its associated complications. The increasing prevalence of cardiovascular risk factors, population ageing, and burden on both the economy and the healthcare system have led to the development of new diagnostic and therapeutic strategies in the field. The better understanding or discovery of new pathophysiological mechanisms and molecules modulating various signaling pathways involved in atherosclerosis have led to the development of potential new biomarkers, with key role in early, subclinical diagnosis. The evolution of technological processes in medicine has shifted the attention of researchers from the profiling of classical risk factors to the identification of new biomarkers such as midregional pro-adrenomedullin, midkine, stromelysin-2, pentraxin 3, inflammasomes, or endothelial cell-derived extracellular vesicles. These molecules are seen as future therapeutic targets associated with decreased morbidity and mortality through early diagnosis of atherosclerotic lesions and future research directions.

Biomarkers for Detecting Kidney Dysfunction in Type-2 Diabetics and Diabetic Nephropathy Subjects: A Case-Control Study to Identify Potential Biomarkers of DN to Stratify Risk of Progression in T2D Patients

INTRODUCTION

Currently there are no biomarkers that are predictive of when patients with type-2 diabetes (T2D) will progress to more serious kidney disease i.e., diabetic nephropathy (DN). Biomarkers that could identify patients at risk of progression would allow earlier, more aggressive treatment intervention and management, reducing patient morbidity and mortality.

MATERIALS AND METHODS

Study participants (N=88; control n=26; T2D n=32; DN n=30) were recruited from the renal unit at Antrim Area Hospital, Antrim, UK; Whiteabbey Hospital Diabetic Clinic, Newtownabbey, UK; Ulster University (UU), Belfast, UK; and the University of the Third Age (U3A), Belfast, UK; between 2019 and 2020. Venous blood and urine were collected with a detailed clinical history for each study participant.

RESULTS

In total, 13/25 (52.0%) biomarkers measured in urine and 25/34 (73.5%) biomarkers measured in serum were identified as significantly different between control, T2D and DN participants. DN patients, were older, smoked more, had higher systolic blood pressure and higher serum creatinine levels and lower eGFR function. Serum biomarkers significantly inversely correlated with eGFR.

CONCLUSION

This pilot-study identified several serum biomarkers that could be used to predict progression of T2D to more serious kidney disease: namely, midkine, sTNFR1 and 2, H-FABP and Cystatin C. Our results warrant confirmation in a longitudinal study using a larger patient cohort.