Statins influence epithelial expression of the anti-microbial peptide LL-37/hCAP-18 independently of the mevalonate pathway

Cathelicidin in Urinary Tract Diseases: Diagnostic, Prognostic and Therapeutic Potential of an Evolutionary Conserved Antimicrobial Protein

Despite being one of the most common infectious diseases, urinary tract infections (UTIs) still represent a challenge for clinicians to diagnose and treat, especially in the era of growing antibiotic resistance among uropathogenic bacteria. Recent studies investigating the pathophysiology of UTIs have discovered the prominent role of antimicrobial peptides in the urinary tract defense system. Cathelicidin is an evolutionary conserved antimicrobial peptide encoded by one single gene in humans. Except for being stored in neutrophil cytoplasmic granules, cathelicidin is produced by uroepithelial cells rapidly upon contact with a uropathogen, even before leukocytes invade the urinary tract. In addition to its bactericidal effect, cathelicidin acts as a chemoattractant for multiple immune cells and a potent inductor of numerous cytokine synthesis. Such a crucial role in the initial pathogenesis of a UTI makes cathelicidin a potential biomarker for an early UTI diagnosis. Indeed, multiple studies over the last two decades have proved the potential clinical utility of cathelicidin as a UTI diagnostic biomarker. Furthermore, since patients after the resolution of a UTI have been found to express a lower urinary cathelicidin level than healthy controls, decreased cathelicidin levels have been suggested as a risk factor for developing UTI recurrence. Therefore, measuring cathelicidin levels in urine might help in distinguishing patients with a higher risk for a recurrent UTI. Interestingly, except in UTIs, cathelicidin has also been evaluated in other urinary tract diseases and proposed as a biomarker for diagnosing severe vesicoureteral reflux (VUR) and for recognizing renal scar development in patients with VUR. Finally, a prominent role in UTI pathogenesis also makes cathelicidin an attractive therapeutic target for treating UTIs and, lately, different therapeutic agents up-regulating cathelicidin expression have been investigated in this matter. Therefore, the present review aims to summarize the current body of knowledge on the diagnostic, prognostic and therapeutic potential of cathelicidin in urinary tract diseases. For this purpose, three databases (Scopus, Medline and Web of Science) were extensively searched to cover all the published articles. This exhaustive review will update clinicians on the contemporary state of knowledge about the potential clinical utility of cathelicidin in urinary tract diseases and hopefully encourage further research, resulting in improvement in the current management of urinary tract diseases.

Prognostic Impacts of LL-37 in Relation to Lipid Profiles of Patients with Myocardial Infarction: A Prospective Cohort Study

Background. In vivo studies show that LL-37 inhibits the progression of atherosclerosis and predicts a lower risk of recurrent ischemia in patients with acute myocardial infarction (AMI), which could be mediated by the modulation of lipid metabolism. The current study aimed to investigate the effects of various lipid contents on the prognostic impacts of LL-37 in patients with AMI. Methods. A total of 1567 consecutive AMI patients were prospectively recruited from March 2017 to January 2020. Patients were firstly stratified into two groups by the median level of LL-37 and then stratified by levels of various lipid contents and proprotein convertase subtilisin/kexin type 9 (PCSK9). Cox regression with multiple adjustments was performed to analyze associations between LL-37, lipid profiles, PCSK9, and various outcomes. The primary outcome was major adverse cardiovascular event (MACE), a composite of all-cause death, recurrent MI, and ischemic stroke. Results. During a median follow-up of 786 (726−1107) days, a total of 252 MACEs occurred. A high level of LL-37 was associated with lower risk of MACE in patients with elevated lipoprotein(a) (≥300 mg/L, hazard ratio (HR): 0.49, 95% confidence interval (CI): 0.29−0.86, p = 0.012) or PCSK9 levels above the median (≥47.4 ng/mL, HR: 0.57, 95% CI: 0.39−0.82, p < 0.001), which was not observed for those without elevated lp(a) (<300 mg/L, HR: 0.96, 95% CI: 0.70−1.31, p = 0.781, pinteraction = 0.035) or PCSK9 (<47.4 ng/mL, HR: 1.02, 95% CI: 0.68−1.54, p = 0.905, pinteraction = 0.032). Conclusions. For patients with AMI, a high level of LL-37 was associated with lower ischemic risk among patients with elevated lp(a) and PCSK9.

Atorvastatin inhibits the proliferation of MKN45-derived gastric cancer stem cells in a mevalonate pathway-independent manner

Gastric cancer stem cells (GCSCs) are a major cause of radioresistance and chemoresistance in gastric cancer (GC). Therefore, targeting GCSCs is regarded as a powerful strategy for the effective treatment of GC. Atorvastatin is a widely prescribed cholesterol-lowering drug that inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a rate-limiting enzyme in the mevalonate pathway. The anticancer activity of atorvastatin, a repurposed drug, is being investigated; however, its therapeutic effect and molecular mechanism of action against GCSCs remain unknown. In this study, we evaluated the anticancer effects of atorvastatin on MKN45-derived GCSCs. Atorvastatin significantly inhibited the proliferative and tumorsphere-forming abilities of MKN45 GCSCs in a mevalonate pathway-independent manner. Atorvastatin induced cell cycle arrest at the G0/G1 phase and promoted apoptosis by activating the caspase cascade. Furthermore, atorvastatin exerted an antiproliferative effect against MKN45 GCSCs by inhibiting the expression of cancer stemness markers, such as CD133, CD44, integrin α6, aldehyde dehydrogenase 1A1, Oct4, Sox2, and Nanog, through the downregulation of β-catenin, signal transducer and activator of transcription 3, and protein kinase B activities. Additionally, the combined treatment of atorvastatin and sorafenib, a multi-kinase targeted anticancer drug, synergistically suppressed not only the proliferation and tumorsphere formation of MKN45 GCSCs but also the in vivo tumor growth in a chick chorioallantoic membrane model implanted with MKN45 GCSCs. These findings suggest that atorvastatin can therapeutically eliminate GCSCs.

Metformin strengthens uroepithelial immunity against E. coli infection

Urinary tract infection frequently caused by E. coli is one of the most common bacterial infections. Increasing antibiotic resistance jeopardizes successful treatment and alternative treatment strategies are therefore mandatory. Metformin, an oral antidiabetic drug, has been shown to activate macrophages in the protection against certain infecting microorganisms. Since epithelial cells often form the first line of defense, we here investigated the effect on uroepithelial cells during E. coli infection. Metformin upregulated the human antimicrobial peptides cathelicidin LL-37 and RNase7 via modulation of the TRPA1 channel and AMPK pathway. Interestingly, metformin stimulation enriched both LL-37 and TRPA1 in lysosomes. In addition, metformin specifically increased nitric oxide and mitochondrial, but not cytosolic ROS. Moreover, metformin also triggered mRNA expression of the proinflammatory cytokines IL1B, CXCL8 and growth factor GDF15 in human uroepithelial cells. The GDF15 peptide stimulated macrophages increased LL-37 expression, with increased bacterial killing. In conclusion, metformin stimulation strengthened the innate immunity of uroepithelial cells inducing enhanced extracellular and intracellular bacterial killing suggesting a favorable role of metformin in the host defense.

Statins: Epidrugs with effects on endothelial health?

BACKGROUND

Epigenetic events involving the methylation of CpG cites in DNA, histone modifications and noncoding RNAs correlated with many essential processes in human cells and diseases, such as cancer and cardiovascular diseases. HMG-CoA reductase inhibitors (statins)-the LDL cholesterol-lowering drugs-are broadly used in cardio- and cerebro-vascular diseases. It is well established that statins exert pleiotropic functions, but how they exert effects on epigenetic modifications independently of HMG-CoA reductase inhibition is not yet clear. Thereby, understanding these mechanisms may pave the way for further clinical application of statin therapy.

DESIGN

Following and electronic database search, studies reporting substantial effects of statins on epigenetic reprogramming in both cultured cells and in vivo models were retrieved and reviewed.

RESULTS

Epigenetic mechanisms play an essential role in cellular development and function, and data collected in the past few years have revealed that many of the pleiotropic properties of statins are mediated by epigenetic mechanisms. Furthermore, those 'nonclassical' effects are not limited to CV field but they would extend to other conditions such as malignancies.

CONCLUSION

This review suggests that the epigenetic effects of statins mediate, at least in part, the pleiotropic actions of these drugs but further validation of such effects in clinical studies is yet to be provided.

Significance of LL-37 on Immunomodulation and Disease Outcome

LL-37, also called cathelicidin, is an important part of the human immune system, which can resist various pathogens. A plethora of experiments have demonstrated that it has the multifunctional effects of immune regulation, in addition to antimicrobial activity. Recently, there have been increasing interest in its immune function. It was found that LL-37 can have two distinct functions in different tissues and different microenvironments. Thus, it is necessary to investigate LL-37 immune functions from the two sides of the same coin. On the one side, LL-37 promotes inflammation and immune response and exerts its anti-infective and antitumor effects; on the other side, it has the ability to inhibit inflammation and promote carcinogenesis. This review presents a brief summary of its expression, structure, and immunomodulatory effects as well as brief discussions on the role of this small peptide as a key factor in the development and treatment of various inflammation-related diseases and cancers.