Evaluation of Circulating MicroRNA Biomarkers in the Acute Pancreatic Injury Dog Model

Exocrine pancreatic inflammation in canine diabetes mellitus - An active offender?

The purpose of this review is to examine the current scientific literature regarding the interplay between the exocrine and endocrine pancreas, specifically the role of the exocrine pancreas in the pathogenesis of canine diabetes mellitus. β-cell death caused by exocrine pancreatic inflammation is thought to be an under-recognised contributor to diabetes mellitus in dogs, with up to 30 % of canine diabetic patients with concurrent evidence of pancreatitis at post-mortem examination. Current diagnostics for pancreatitis are imprecise, and treatments for both diseases individually have their own limitations: diabetes through daily insulin injections, which has both welfare and financial implications for the stakeholders, and pancreatitis through treatment of clinical signs, such as analgesia and anti-emetics, rather than targeted treatment of the underlying cause. This review will consider the evidence for exocrine pancreatic inflammation making an active contribution to pancreatic β-cell loss and insulin-deficiency diabetes in the dog and explore current and potential future diagnostic and treatment avenues to improve outcomes for these patients.

Candidate circulating microRNA biomarkers in dogs with chronic pancreatitis

BACKGROUND

Pancreatitis is an important cause of disease and death in dogs. Available circulating biomarkers are not sufficiently sensitive and specific for a definitive diagnosis.

HYPOTHESIS

Circulating microRNAs would be differentially expressed in dogs with chronic pancreatitis and could have potential as diagnostic biomarkers.

ANIMALS

Healthy controls (n = 19) and dogs with naturally occurring pancreatitis (n = 17).

METHODS

A retrospective case-control study. Dogs with pancreatitis were included if they satisfied diagnostic criteria for pancreatitis as adjudicated by 3 experts. MicroRNA was extracted from stored serum samples and sequenced. Reads were mapped to mature microRNA sequences in the canine, mouse, and human genomes. Differentially expressed microRNAs were identified and the potential mechanistic relevance explored using Qiagen Ingenuity Pathway Analysis (IPA).

RESULTS

Reads mapping to 196 mature microRNA sequences were detected. Eight circulating microRNAs were significantly differentially expressed in dogs with pancreatitis (≥2-fold change and false discovery rate <0.05). Four of these mapped to the canine genome (cfa-miR-221, cfa-miR-222, cfa-miR-23a, and cfa-miR-205). Three mapped to the murine genome (mmu-miR-484, mmu-miR-6240, mmu-miR-101a-3p) and 1 to the human genome (hsa-miR-1290). Expression in dogs with pancreatitis was higher for 7 microRNAs and lower for mmu-miR-101a-3p. Qiagen IPA demonstrated a number of the differently expressed microRNAs are involved in a common pancreatic inflammatory pathway.

CONCLUSIONS

The significantly differentially expressed microRNAs represent promising candidates for further validation as diagnostic biomarkers for canine pancreatitis.

The Use of Diets in the Diagnosis and Treatment of Common Gastrointestinal Diseases in Dogs and Cats

The nutritional health of dogs and cats is important to pet owners around the world. Nutrition is inextricably linked to the health of the gastrointestinal system and vice versa. Gastrointestinal signs, such as vomiting, diarrhea, anorexia, or weight loss, are one of the most common reasons that dog and cat owners make non-routine appointments with veterinarians. Those patients are evaluated systematically to identify and/or rule out the causes of the symptoms. Some causes of chronic diarrhea are within the gastrointestinal tract while others are secondary to pathogenic factors outside the digestive system. Some useful biomarkers of chronic intestinal disease (enteropathy) exist in serum and feces. After determination that the clinical signs are due to primary gastrointestinal disease and that there is no parasitism, specific diets are used for at least two weeks. There are several types of diets for pets with chronic enteropathies. There are limited ingredient diets and hydrolyzed protein diets with reduced levels of allergens. There are also highly digestible and fiber-enhanced diets. Some diets contain probiotics and/or prebiotics. If symptoms do not improve and the patient is stable, a diet from a different class may be tried. For chronic enteropathies, the prognosis is generally good for symptom resolution or at least improvement. However, if interventions with novel diets do not ameliorate the symptoms of chronic enteropathy, then antibiotic, anti-inflammatory, or immunosuppressant therapy or further, more invasive diagnostics such as taking an intestinal biopsy, may be indicated. Pancreatitis is a common gastrointestinal disease in dogs and cats and patients may present with mild to severe disease. Many patients with mild to moderate disease can be successfully treated with early supportive care, including feeding a low-fat diet. A novel pharmaceutical, fuzapladib (Panoquell-CA1) looks very promising for treating more severe forms of acute pancreatitis in dogs. Maintenance on a low-fat diet may prevent pancreatitis in at-risk dogs. Future advances in medicine will allow pet owners and veterinarians to use dietary management to maximize the health of their dogs and cats.

A review on microRNA detection and expression studies in dogs

MicroRNAs (miRNAs) are small non-coding RNAs that function by post-transcriptional regulation of gene expression. Their stability and abundance in tissue and body fluids makes them promising potential tools for both the diagnosis and prognosis of diseases and attractive therapeutic targets in humans and dogs. Studies of miRNA expression in normal and disease processes in dogs are scarce compared to studies published on miRNA expression in human disease. In this literature review, we identified 461 peer-reviewed papers from database searches using the terms "canine," "dog," "miRNA," and "microRNA"; we screened 244 for inclusion criteria and then included a total of 148 original research peer-reviewed publications relating to specific miRNA expression in canine samples. We found an overlap of miRNA expression changes between the four groups evaluated (normal processes, non-infectious and non-inflammatory conditions, infectious and/or inflammatory conditions, and neoplasia) in 39 miRNAs, 83 miRNAs in three of the four groups, 110 miRNAs in two of the three groups, where 158 miRNAs have only been reported in one of the groups. Additionally, the mechanism of action of these overlapping miRNAs varies depending on the disease process, elucidating a need for characterization of the mechanism of action of each miRNA in each disease process being evaluated. Herein we also draw attention to the lack of standardization of miRNA evaluation, consistency within a single evaluation method, and the need for standardized methods for a direct comparison.

The Role of MicroRNAs in Pancreatitis Development and Progression

Pancreatitis (acute and chronic) is an inflammatory disease associated with significant morbidity, including a high rate of hospitalization and mortality. MicroRNAs (miRs) are essential post-transcriptional modulators of gene expression. They are crucial in many diseases' development and progression. Recent studies have demonstrated aberrant miRs expression patterns in pancreatic tissues obtained from patients experiencing acute and chronic pancreatitis compared to tissues from unaffected individuals. Increasing evidence showed that miRs regulate multiple aspects of pancreatic acinar biology, such as autophagy, mitophagy, and migration, impact local and systemic inflammation and, thus, are involved in the disease development and progression. Notably, multiple miRs act on pancreatic acinar cells and regulate the transduction of signals between pancreatic acinar cells, pancreatic stellate cells, and immune cells, and provide a complex interaction network between these cells. Importantly, recent studies from various animal models and patients' data combined with advanced detection techniques support their importance in diagnosing and treating pancreatitis. In this review, we plan to provide an up-to-date summary of the role of miRs in the development and progression of pancreatitis.

Evaluation of serum miR-216a and miR-375 as biomarkers in dogs with acute pancreatitis

BACKGROUND

Serum microRNAs have emerged as biomarkers of various diseases. Overexpression of serum miR-216a and miR-375 occurs in dogs with experimentally induced acute pancreatitis (AP).

OBJECTIVES

To identify the possibility of using serum miR-216a and miR-375 as biomarkers for the diagnosis and evaluation of treatment response in dogs with naturally occurring AP.

ANIMALS

Twenty-one dogs with AP and 20 healthy dogs.

METHODS

Cross-sectional study. The relative expression of serum hsa-miR-216a-5p, cfa-miR-216a, and cfa-miR-375 were analyzed using reverse transcription and real-time PCR.

RESULTS

A significant difference in the serum expression of cfa-miR-375 was found between dogs with AP (median [interquartile range] 3.59 [1.55-24.52]-fold) and healthy dogs (0.81 [0.54-2.21]-fold, P < .001), and no significant differences were observed in hsa-miR-216a-5p and cfa-miR-216a (P > .05). The area under the receiver operating characteristic curve of serum cfa-miR-375 for differentiating between AP dogs and healthy dogs was 0.84 (95% confidence interval [CI]: 0.71-0.96). The expressions of hsa-miR-216a-5p and cfa-miR-375 were positively correlated with the concentrations of serum C-reactive protein (r_s  = .46, r_s  = .48, respectively), but not with the serum specific canine pancreatic lipase. The expression of cfa-miR-375 was significantly less after treatment in dogs with AP (P = .02).

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum cfa-miR-375 could be a potential biomarker for the diagnosis and evaluation of treatment response of AP in dogs. In addition, miR-216a and miR-375 could be associated with inflammatory processes in dogs with AP.

Fighting Fire with Fire: Exosomes and Acute Pancreatitis-Associated Acute Lung Injury

Acute pancreatitis (AP) is a prevalent clinical condition of the digestive system, with a growing frequency each year. Approximately 20% of patients suffer from severe acute pancreatitis (SAP) with local consequences and multi-organ failure, putting a significant strain on patients' health insurance. According to reports, the lungs are particularly susceptible to SAP. Acute respiratory distress syndrome, a severe type of acute lung injury (ALI), is the primary cause of mortality among AP patients. Controlling the mortality associated with SAP requires an understanding of the etiology of AP-associated ALI, the discovery of biomarkers for the early detection of ALI, and the identification of potentially effective drug treatments. Exosomes are a class of extracellular vesicles with a diameter of 30-150 nm that are actively released into tissue fluids to mediate biological functions. Exosomes are laden with bioactive cargo, such as lipids, proteins, DNA, and RNA. During the initial stages of AP, acinar cell-derived exosomes suppress forkhead box protein O1 expression, resulting in M1 macrophage polarization. Similarly, macrophage-derived exosomes activate inflammatory pathways within endothelium or epithelial cells, promoting an inflammatory cascade response. On the other hand, a part of exosome cargo performs tissue repair and anti-inflammatory actions and inhibits the cytokine storm during AP. Other reviews have detailed the function of exosomes in the development of AP, chronic pancreatitis, and autoimmune pancreatitis. The discoveries involving exosomes at the intersection of AP and acute lung injury (ALI) are reviewed here. Furthermore, we discuss the therapeutic potential of exosomes in AP and associated ALI. With the continuous improvement of technological tools, the research on exosomes has gradually shifted from basic to clinical applications. Several exosome-specific non-coding RNAs and proteins can be used as novel molecular markers to assist in the diagnosis and prognosis of AP and associated ALI.

Advances in the diagnosis of acute pancreatitis in dogs

In the last 20 years, the diagnosis of pancreatitis has become more frequent as a result of improved diagnostic modalities such as abdominal ultrasound examination, advanced imaging, and immunoassays for the measurement of pancreatic lipase. Our aim is to provide a state‐of‐the‐art overview of the clinical diagnosis of acute pancreatitis (AP) in dogs with a particular focus on pancreatic lipase assay validation and clinical performance, in addition to advanced imaging modalities. We also discuss the potential indications for cytology and histopathology in dogs with suspected AP.

Regulation of Pancreatic Fibrosis by Acinar Cell-Derived Exosomal miR-130a-3p via Targeting of Stellate Cell PPAR-γ

Introduction

As endogenous miRNA carriers, exosomes play a role in the pathophysiological processes of various diseases. However, their functions and regulation mechanisms in pancreatic fibrosis remain unclear.

Methods

In this study, an RNA microarray was used to detect differentially expressed exosomal miR-130a-3p in AR42J cells before and after taurolithocholate (TLC) treatment. mRNA-seq was used to screen differentially expressed genes before and after pancreatic stellate cell (PSC) activation. We used the STRING database to construct a protein-protein interaction (PPI) network for differentially expressed genes, used CytoNCA to analyze the centrality of the PPI network, and identified 10 essential proteins in the biological network. Then, the TargetScan and miRanda databases were used to predict the target genes of miR-130a-3p. The intersections of the target genes and the mRNAs encoding the 10 essential proteins were identified to construct miR-130a-3p/peroxisome proliferator-activated receptor gamma (PPAR-γ) pairs. Fluorescence labeling of exosomes and dynamic tracing showed that exosomes can fuse with the cell membranes of PSCs and transport miR-130a-3p into PSCs. A luciferase reporter gene assay was used to confirm that miR-130a-3p can bind to PPAR-γ to inhibit PPAR-γ expression. In vitro and in vivo functional experiments were performed for gain-of-function studies and loss-of-function studies, respectively.

Results

The studies showed that acinar cell-derived exosomal miR-130a-3p promotes PSC activation and collagen formation through targeting of stellate cellular PPAR-γ. Knockdown of miR-130a-3p significantly improved pancreatic fibrosis. Notably, miR-130a-3p knockdown reduced serum levels of hyaluronic acid (HA) and β-amylase and increased the C-peptide level to protect endocrine and exocrine pancreatic functions and the function of endothelial cells.

Conclusion

This study revealed that the exosomal miR-130a-3p/PPAR-γ axis participates in PSC activation and the mechanism of chronic pancreatitis (CP) with fibrosis, thus providing a potential new target for the treatment of chronic pancreatic fibrosis.

Recent progress in the use of microRNAs as biomarkers for drug-induced toxicities in contrast to traditional biomarkers: A comparative review

microRNAs (miRNAs) are small non-coding RNAs with 18-25 nucleotides. They play key regulatory roles in versatile biological process including development and apoptosis, and in disease pathogenesis, for example carcinogenesis, by negatively regulating gene expression. miRNAs often exhibit characteristics suitable for biomarkers such as tissue-specific expression patterns, high stability in serum/plasma, and change in abundance in circulation immediately after toxic injury. Since the discovery of circulating miRNAs in extracellular biological fluids in 2008, there have been many reports on the use of miRNAs as biomarkers for various diseases including cancer and organ injury in humans and experimental animals. In this review article, we have summarized the utility and limitation of circulating miRNAs as safety/toxicology biomarkers for specific tissue injuries including liver, skeletal muscle, heart, retina, and pancreas, by comparing them with conventional protein biomarkers. We have also covered the discovery of miRNAs in serum/plasma and their stability, the knowledge of which is essential for understanding the kinetics of miRNA biomarkers. Since numerous studies have reported the use of these circulating miRNAs as safety biomarkers with high sensitivity and specificity, we believe that circulating miRNAs can promote pre-clinical drug development and improve the monitoring of tissue injuries in clinical pharmacotherapy.

MicroRNAs as systemic biomarkers to assess distress in animal models for gastrointestinal diseases

Severity assessment of animal experiments is mainly conducted by using subjective parameters. A widely applicable biomarker to assess animal distress could contribute to an objective severity assessment in different animal models. Here, the distress of three murine animal models for gastrointestinal diseases was assessed by multiple behavioral and physiological parameters. To identify possible new biomarkers for distress 750 highly conserved microRNAs were measured in the blood plasma of mice before and after the induction of pancreatitis. Deregulated miRNA candidates were identified and further quantified in additional animal models for pancreatic cancer and cholestasis. MiR-375 and miR-203 were upregulated during pancreatitis and down regulated during cholestasis, whereas miR-132 was upregulated in all models. Correlation between miR-132 and plasma corticosterone concentrations resulted in the highest correlation coefficient, when compared to the analysis of miR-375, miR-203 and miR-30b. These results indicate that miR-132 might function as a general biomarker for distress, whereas the other miRNAs were altered in a disease specific manner. In conclusion, plasma miRNA profiling may help to better characterize the level of distress in mouse models for gastrointestinal diseases.

MicroRNAs in acute pancreatitis: From pathogenesis to novel diagnosis and therapy

Acute pancreatitis (AP) is an inflammatory disorder initiated by activation of pancreatic zymogens, leading to pancreatic injury and systemic inflammatory response. MicroRNAs (miRNAs) have emerged as important regulators of gene expression and key players in human physiological and pathological processes. Discoveries over the past decade have confirmed that altered expression of miRNAs is implicated in the pathogenesis of AP. Indeed, a number of miRNAs have been found to be dysregulated in various cell types involved in AP such as acinar cells, macrophages, and lymphocytes. These aberrant miRNAs can regulate acinar cell necrosis and apoptosis, local and systemic inflammatory response, thereby contributing to the initiation and progression of AP. Moreover, patients with AP possess unique miRNA signatures when compared with healthy individuals or those with other diseases. In view of their stability and easy detection, therefore, miRNAs have the potential to act as biomarkers for the diagnosis and assessment of patients with AP. In this review, we provide an overview of the novel cellular and molecular mechanisms underlying the roles of miRNAs during the disease processes of AP, as well as the potential diagnosis and therapeutic biomarkers of miRNAs in patients with AP.

Effects of miR-7a-5p expression on proliferation and apoptosis of acinar cells in acute pancreatitis

BACKGROUND

Pancreatic acinar cell proliferation and apoptosis are closely related to the development of acute pancreatitis (AP). MicroRMAs (miRNAs) participate in cell proliferation and apoptosis by regulating target gene expression, and identification of miRNA molecules related to pancreatic acinar cell proliferation and apoptosis is important for clinical diagnosis and treatment of AP.

AIM

To investigate the effect of miRNA-7a-5p on the proliferation and apoptosis of acinar cells in AP and the underlying mechanism.

METHODS

A caerulin-induced AP model was constructed using pancreatitis acinar AR42J cells. qRT-PCR and Western blot were used to detect the expression of miR-7a-5p and protein inhibitor of activated signal transducer and activator of transcription 1 (PIAS1) in control AR42J cells and cerulein induced AR42J cells. After anti-miR-7a-5p and pcDNA-PIAS1 were transfected into AR42J cells, the proliferation of AR42J cells was detected by MTT assay, and the apoptosis of AR42J cells was detected by flow cytometry. The luciferase reporter system was used to detect the targeted regulation of PIAS1 gene by miR-7a-5p, and Western blot was used to detect the regulation of PIAS1 protein expression by miR-7a-5p. To silence PIAS1 expression by RNA interference, si-PIAS1 and its negative control plasmid were transfected into anti-miR-7a-5p treated AR42J cells, and the proliferation and apoptosis of AR42J cells were detected.

RESULTS

Compared with control AR42J cells, the expression level of miR-7a-5p was significantly increased in cerulein induced AR42J cells (P < 0.05), and the expression of PIAS1 protein was significantly decreased (P < 0.05). Inhibition of miR-7a-5p expression promoted proliferation and inhibited apoptosis of AR42J cells. MiR-7a-5p could negatively regulate the expression of its target gene PIAS1. Overexpression of PIAS1 promoted proliferation and inhibited apoptosis of AR42J cells. Compared with the anti-miR-7a-5p + si-NC group, the activity of AR42J cells in the anti-miR-7a-5p + si-PIAS1 group was significantly decreased (P < 0.05), and the apoptosis rate was significantly increased (P < 0.05).

CONCLUSION

MiR-7a-5p can promote the apoptosis of acinar cells and reduce the proliferation of cells in AP by inhibiting the expression of PIAS1.

Evaluation of the Relative Performance of Pancreas-Specific MicroRNAs in Rat Plasma as Biomarkers of Pancreas Injury

Drug-induced pancreatic injury (DIPI) has become linked in recent years to many commonly prescribed medications from several pharmacological classes. Diagnosis is currently most often focused on identification of acute pancreatitis and generally based on subjective clinical assessment and serum amylase and lipase enzymatic activity, which have been criticized as being insufficiently sensitive and specific. The lack of novel noninvasive biomarkers of DIPI can impede the advancement of drug candidates through nonclinical development and translation into clinical settings. Pancreas-specific microRNAs (miRNAs) are currently being evaluated as biomarkers of DIPI that may outperform and/or add value to the interpretation of amylase and lipase. To assess the relative performance of these novel miRNAs, a comprehensive evaluation was conducted to determine the sensitivity and specificity of detecting DIPI in rats. Four miRNAs were evaluated (miR-216a-5p, miR-216b-5p, miR-217-5p, and miR-375-3p) in plasma from 10 studies in which rats were treated with known pancreatic toxicants to assess sensitivity, and from 10 different studies in which toxicity was evident in tissues other than pancreas to assess specificity. The candidate miRNA biomarker performance was compared with amylase and lipase, and receiver operator characteristics (ROC) were determined. Analysis of ROCs demonstrated that all four miRNAs outperformed amylase and lipase in monitoring acute pancreatic injury defined as acinar cell degeneration/necrosis. Specifically, miR-217-5p had the highest performance among all biomarkers assessed. The increased sensitivity and specificity of these miRNAs support their use as biomarkers of DIPI, thereby adding value to the interpretation of amylase and lipase measurements in nonclinical studies. The potential for miRNAs to serve as translational biomarkers in the clinic for the monitoring of DIPI is also supported by this investigation.