Elevation of Tear MMP-9 Concentration as a Biomarker of Inflammation in Ocular Pathology by Antibody Microarray Immunodetection Assays

Validation of a rapid collagenase activity detection technique based on fluorescent quenched gelatin with synovial fluid samples

BACKGROUND

Measuring collagenase activity is crucial in the field of joint health and disease management. Collagenases, enzymes responsible for collagen degradation, play a vital role in maintaining the balance between collagen synthesis and breakdown in joints. Dysregulation of collagenase activity leads to joint tissue degradation and diseases such as rheumatoid arthritis and osteoarthritis. The development of methods to measure collagenase activity is essential for diagnosis, disease severity assessment, treatment monitoring, and identification of therapeutic targets.

RESULTS

This study aimed to validate a rapid collagenase activity detection technique using synovial fluid samples. Antibody microarray analysis was initially performed to quantify the levels of matrix metalloproteinase-9 (MMP-9), a major collagenase in joints. Subsequently, the developed gelatin-based test utilizing fluorescence measurement was used to determine collagenase activity. There was a significant correlation between the presence of MMP-9 and collagenase activity. In addition, Lower Limit of Detection and Upper Limit of Detection can be preliminary estimated as 8 ng/mL and 48 ng/mL respectively.

CONCLUSIONS

The developed technique offers a potential point-of-care assessment of collagenase activity, providing real-time information for clinicians and researchers. By accurately quantifying collagenase activity, healthcare professionals can optimize patient care, improve treatment outcomes, and contribute to the understanding and management of joint-related disorders. Further research and validation are necessary to establish the full potential of this rapid collagenase activity detection method in clinical practice.

Inflammatory Bowel Disease: A Comprehensive Analysis of Molecular Bases, Predictive Biomarkers, Diagnostic Methods, and Therapeutic Options

In inflammatory bowel diseases (IBDs), such as Crohn's disease (CD) and ulcerative colitis (UC), the immune system relentlessly attacks intestinal cells, causing recurrent tissue damage over the lifetime of patients. The etiology of IBD is complex and multifactorial, involving environmental, microbiota, genetic, and immunological factors that alter the molecular basis of the organism. Among these, the microbiota and immune cells play pivotal roles; the microbiota generates antigens recognized by immune cells and antibodies, while autoantibodies target and attack the intestinal membrane, exacerbating inflammation and tissue damage. Given the altered molecular framework, the analysis of multiple molecular biomarkers in patients proves exceedingly valuable for diagnosing and prognosing IBD, including markers like C reactive protein and fecal calprotectin. Upon detection and classification of patients, specific treatments are administered, ranging from conventional drugs to new biological therapies, such as antibodies to neutralize inflammatory molecules like tumor necrosis factor (TNF) and integrin. This review delves into the molecular basis and targets, biomarkers, treatment options, monitoring techniques, and, ultimately, current challenges in IBD management.

Serological Antibodies against Kidney, Liver, and Spleen Membrane Antigens as Potential Biomarkers in Patients with Immune Disorders

Immune disorders arise from complex genetic and environmental factors, which lead to dysregulation at the cellular and inflammatory levels and cause tissue damage. Recent research highlights the crucial role of reactive antibodies in autoimmune diseases and graft rejection, but their complex determination poses challenges for clinical use. Therefore, our study aimed to ascertain whether the presence of reactive antibodies against membrane antigens in tissues from both animal models and humans could serve as biomarkers in patients with autoimmune disorders. To address this issue, we examined the binding profile of serological antibodies against a diverse panel of cell membranes from the spleen, liver, and kidney tissues of monkeys, rats, and humans. After developing the cell membrane microarrays, human sera were immunologically assayed. The study was first conducted on sera from two groups, healthy subjects and patients with inflammatory and autoimmune disorders, and then optimized for kidney transplant patient sera. A significant increase in antibody reactivity against specific monkey kidney and spleen membranes was observed in the serum of patients with lupus nephritis, while kidney transplant patients showed a significant enhancement against human tissues and human embryonic kidney 293 cells. These results show the potential importance for clinical and basic research purposes of studying the presence of specific IgG against membrane antigens in patients' serum as potential biomarkers of immune disorders. However, it is important to note that these results need to be verified in further studies with a larger sample size to confirm their relevance.

Neuroinflammation in the Evolution of Motor Function in Stroke and Trauma Patients: Treatment and Potential Biomarkers

Neuroinflammation has a significant impact on different pathologies, such as stroke or spinal cord injury, intervening in their pathophysiology: expansion, progression, and resolution. Neuroinflammation involves oxidative stress, damage, and cell death, playing an important role in neuroplasticity and motor dysfunction by affecting the neuronal connection responsible for motor control. The diagnosis of this pathology is performed using neuroimaging techniques and molecular diagnostics based on identifying and measuring signaling molecules or specific markers. In parallel, new therapeutic targets are being investigated via the use of bionanomaterials and electrostimulation to modulate the neuroinflammatory response. These novel diagnostic and therapeutic strategies have the potential to facilitate the development of anticipatory patterns and deliver the most beneficial treatment to improve patients' quality of life and directly impact their motor skills. However, important challenges remain to be solved. Hence, the goal of this study was to review the implication of neuroinflammation in the evolution of motor function in stroke and trauma patients, with a particular focus on novel methods and potential biomarkers to aid clinicians in diagnosis, treatment, and therapy. A specific analysis of the strengths, weaknesses, threats, and opportunities was conducted, highlighting the key challenges to be faced in the coming years.

Amphiregulin blockade decreases the levodopa-induced dyskinesia in a 6-hydroxydopamine Parkinson's disease mouse model

BACKGROUND

Levodopa (L-DOPA) is considered the most reliable drug for treating Parkinson's disease (PD) clinical symptoms. Regrettably, long-term L-DOPA therapy results in the emergence of drug-induced abnormal involuntary movements (AIMs) in most PD patients. The mechanisms underlying motor fluctuations and dyskinesia induced by L-DOPA (LID) are still perplexing.

METHODS

Here, we first performed the analysis on the microarray data set (GSE55096) from the gene expression omnibus (GEO) repository and identified the differentially expressed genes (DEGs) using linear models for microarray analysis (Limma) R packages from the Bioconductor project. 12 genes (Nr4a2, Areg, Tinf2, Ptgs2, Pdlim1, Tes, Irf6, Tgfb1, Serpinb2, Lipg, Creb3l1, Lypd1) were found to be upregulated. Six genes were validated on quantitative polymerase chain reaction and subsequently, Amphiregulin (Areg) was selected (based on log2 fold change) for further experiments to unravel its involvement in LID. Areg LV_shRNA was used to knock down Areg to explore its therapeutic role in the LID model.

RESULTS

Western blotting and immunofluorescence results show that AREG is significantly expressed in the LID group relative to the control. Dyskinetic movements in LID mice were alleviated by Areg knockdown, and the protein expression of delta FOSB, the commonly attributable protein in LID, was decreased. Moreover, Areg knockdown reduced the protein expression of P-ERK. In order to ascertain whether the inhibition of the ERK pathway (a common pathway known to mediate levodopa-induced dyskinesia) could also impede Areg, the animals were injected with an ERK inhibitor (PD98059). Afterward, the AIMs, AREG, and ERK protein expression were measured relative to the control group. A group treated with ERK inhibitor had a significant decrease of AREG and phosphorylated ERK protein expression relative to the control group.

CONCLUSION

Taken together, our results indicate unequivocal involvement of Areg in levodopa-induced dyskinesia, thus a target for therapy development.

Lactobacillus fermentum HY7302 Improves Dry Eye Symptoms in a Mouse Model of Benzalkonium Chloride-Induced Eye Dysfunction and Human Conjunctiva Epithelial Cells

(1) We investigated the effects of the Lactobacillus fermentum HY7302 (HY7302) in a mouse model of benzalkonium chloride (BAC)-induced dry eye, and the possibility of using HY7302 as a food supplement for preventing dry eye. (2) The ocular surface of Balb/c mice was exposed to 0.2% BAC for 14 days to induce dry eye (n = 8), and the control group was treated with the same amount of saline (n = 8). HY7302 (1 × 10⁹ CFU/kg/day, 14 days, n = 8) was orally administered daily to the mice, and omega-3 (200 mg/kg/day) was used as a positive control. To understand the mechanisms by which HY7302 inhibits BAC-induced dry eye, we performed an in vitro study using a human conjunctival cell line (clone-1-5c-4). (3) The probiotic HY7302 improved the BAC-induced decreases in the corneal fluorescein score and tear break-up time. In addition, the lactic acid bacteria increased tear production and improved the detached epithelium. Moreover, HY7302 lowered the BAC-induced increases in reactive oxygen species production in a conjunctival cell line and regulated the expression of several apoptosis-related factors, including phosphorylated protein kinase B (AKT), B-cell lymphoma protein 2 (Bcl-2), and activated caspase 3. Also, HY7302 alleviated the expression of pro-inflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, and IL-8, and also regulated the matrix metallopeptidase-9 production in the conjunctival cell line. (4) In this study, we showed that L. fermentum HY7302 helps prevent dry eye disease by regulating the expression of pro-inflammatory and apoptotic factors, and could be used as a new functional food composition to prevent dry eye disease.

A Pilot Study of a Panel of Ocular Inflammation Biomarkers in Patients with Primary Sjögren’s Syndrome

Ocular diseases have a strong impact on individuals, the effects of which extend from milder visual impairment to blindness. Due to this and to their prevalence, these conditions constitute important health, social and economic challenges. Thus, improvements in their early detection and diagnosis will help dampen the impact of these conditions, both on patients and on healthcare systems alike. In this sense, identifying tear biomarkers could establish better non-invasive approaches to diagnose these diseases and to monitor responses to therapy. With this in mind, we developed a solid phase capture assay, based on antibody microarrays, to quantify S100A6, MMP-9 and CST4 in human tear samples, and we used these arrays to study tear samples from healthy controls and patients with Sjögren’s Syndrome, at times concomitant with rheumatoid arthritis. Our results point out that the detection of S100A6 in tear samples seems to be positively correlated to rheumatoid arthritis, consistent with the systemic nature of this autoinflammatory pathology. Thus, we provide evidence that antibody microarrays may potentially help diagnose certain pathologies, possibly paving the way for significant improvements in the future care of these patients.

The Ability of Antibody against Truncated Matrix Metalloproteinase 9 Peptide to Evaluate the Native Protein on Tear Drops of Dry Eye Disease Patients by a Point-of-Care Diagnostic System

Purpose

To obtain a reactive and specific antibody against truncated matrix metalloproteinase 9 (MMP-9), that has reactivity toward the native protein. Precision, accuracy, specificity, and sensitivity were evaluated using a point-of-care test.

Methods

An in silico study was used to confirm the anti peptide truncated MMP-9 is against native MMP-9. After an antibody titer assessment, purification, and characterization, the anti MMP-9 was assessed. The cut-off value was determined using the purified gelatinases of the supernatant HCT 116 cell line. The supernatant was purified by preparative native-polyacrylamide gel electrophoresis based on charge and size of the proteins. Furthermore, quality control (QC) of the results were performed following standard densitometry methods.

Results

A truncated MMP-9 is the major epitope peptide that can trigger the immune system to scavenge for a specific and reactive antibody against the native MMP-9. The MMP-9 native protein is purified from the supernatant of the HCT 116 cell line and the commercially available, full-length MMP-9. The cut-off value was estimated at 30 μg/mL. QC results indicated that the specificity was 80%, sensitivity was 96.7%, accuracy was 91%, and precision was 91.66%. The area under curve was 0.827 (P < 0.001). The positive predictive value was 83%, and the negative predictive value was 96%.

Conclusions

The antibody against the synthetic epitope peptide can detect the native MMP-9. Native MMP-9 is considered the main biomarker in an immunoassay POCT and is used to diagnose dry eye disease (DED). In accordance with QC results, MMP-9 point of care test can be utilized for screening patients suffering from DED.

Enzymes and Enzyme Inhibitors—Applications in Medicine and Diagnosis

This is the first part of a Special Issue on enzymes and enzymes inhibitors and their applications in medicine and diagnosis [...]

Clinical Tear Fluid Proteomics—A Novel Tool in Glaucoma Research

Tear fluid forms the outermost layer of the ocular surface and its characteristics and composition have been connected to various ocular surface diseases. As tear proteomics enables the non-invasive investigation of protein levels in the tear fluid, it has become an increasingly popular approach in ocular surface and systemic disease studies. Glaucoma, which is a set of multifactorial diseases affecting mainly the optic nerve and retinal ganglion cells, has also been studied using tear proteomics. In this condition, the complete set of pathophysiological changes occurring in the eye is not yet fully understood, and biomarkers for early diagnosis and accurate treatment selection are needed. More in-depth analyses of glaucoma tear proteomics have started to emerge only more recently with the implementation of LC-MS/MS and other modern technologies. The aim of this review was to examine the published data of the tear protein changes occurring during glaucoma, its topical treatment, and surgical interventions.