Therapeutic Effectiveness of Anti-RAGE Antibody Administration in a Rat Model of Crush Injury

Rosmarinic acid plus deferasirox inhibits ferroptosis to alleviate crush syndrome-related AKI via Nrf2/Keap1 pathway

BACKGROUND

Myoglobin (Mb) induced death of renal tubular epithelial cells (RTECs) is a major pathological factor in crush syndrome-related acute kidney injury (CS-AKI). It is unclear whether ferroptosis is involved and could be a target for treatment.

PURPOSE

This study aimed to evaluate the potential therapeutic effects of combining the natural small molecule rosemarinic acid (RA) and the iron chelator deferasirox (Dfe) on CS-AKI through inhibition of ferroptosis.

METHODS

Sequencing data were downloaded from the GEO database, and differential expression analysis was performed using the R software limma package. The CS-AKI mouse model was constructed by squeezing the bilateral thighs of mice for 16 h with 1.5 kg weight. TCMK1 and NRK-52E cells were induced with 200 μM Mb and then treated with RA combined with Dfe (Dfe + RA, both were 10 μM). Functional and pathological changes in mouse kidney were evaluated by glomerular filtration rate (GFR) and HE pathology. Immunofluorescence assay was used to detect Mb levels in kidney tissues. The expression levels of ACSL4, GPX4, Keap1, and Nrf2 were analyzed by WB.

RESULTS

We found that AKI mice in the GSE44925 cohort highly expressed the ferroptosis markers ACSL4 and PTGS2. CS-AKI mice showed a rapid decrease in GFR, up-regulation of ACSL4 expression in kidney tissue, and down-regulation of GPX4 expression, indicating activation of the ferroptosis pathway. Mb was found to deposit in renal tubules, and it has been proven to cause ferroptosis in TCMK1 and NRK-52E cells in vitro. We found that Dfe had a strong iron ion scavenging effect and inhibited ACSL4 expression. RA could disrupt the interaction between Keap1 andNrf2, stabilize Nrf2, and promote its nuclear translocation, thereby exerting antioxidant effects. The combination of Dfe and RA effectively reversed Mb induced ferroptosis in RTECs.

CONCLUSION

In conclusion, we found that RA combined with Dfe attenuated CS-AKI by inhibiting Mb-induced ferroptosis in RTECs via activating the Nrf2/Keap1 pathway.

Proteomic analysis of multiple organ dysfunction induced by rhabdomyolysis

Rhabdomyolysis (RM) leads to dysfunction in the core organs of kidney, lung and heart, which is an important reason for the high mortality and disability rate of this disease. However, there is a lack of systematic research on the characteristics of rhabdomyolysis-induced injury in various organs and the underlying pathogenetic mechanisms, and especially the interaction between organs. We established a rhabdomyolysis model, observed the structural and functional changes in kidney, heart, and lung. It is observed that rhabdomyolysis results in significant damage in kidney, lung and heart of rats, among which the pathological damage of kidney and lung was significant, and of heart was relatively light. Meanwhile, we analyzed the differentially expressed proteins (DEPs) in the kidney, heart and lung between the RM group and the sham group based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). In our study, Serpina3n was significantly up-regulated in the kidney, heart and lung. Serpina3n is a secreted protein and specifically inhibits a variety of proteases and participates in multiple physiological processes such as complement activation, inflammatory responses, apoptosis pathways, and extracellular matrix metabolism. It is inferred that Serpina3n may play an important role in multiple organ damage caused by rhabdomyolysis and could be used as a potential biomarker. This study comprehensively describes the functional and structural changes of kidney, heart and lung in rats after rhabdomyolysis, analyzes the DEPs of kidney, heart and lung, and determines the key role of Serpina3n in multiple organ injury caused by rhabdomyolysis. SIGNIFICANCE: This study comprehensively describes the functional and structural changes of kidney, heart and lung in rats after rhabdomyolysis, analyzes the DEPs of kidney, heart and lung, and determines the key role of Serpina3n in multiple organ injury caused by rhabdomyolysis.

Tissue-resident macrophages exacerbate lung injury after remote sterile damage

Remote organ injury, which is a common secondary complication of sterile tissue damage, is a major cause of poor prognosis and is difficult to manage. Here, we report the critical role of tissue-resident macrophages in lung injury after trauma or stroke through the inflammatory response. We found that depleting tissue-resident macrophages rather than disrupting the recruitment of monocyte-derived macrophages attenuated lung injury after trauma or stroke. Our findings revealed that the release of circulating alarmins from sites of distant sterile tissue damage triggered an inflammatory response in lung-resident macrophages by binding to receptor for advanced glycation end products (RAGE) on the membrane, which activated epidermal growth factor receptor (EGFR). Mechanistically, ligand-activated RAGE triggered EGFR activation through an interaction, leading to Rab5-mediated RAGE internalization and EGFR phosphorylation, which subsequently recruited and activated P38; this, in turn, promoted RAGE translation and trafficking to the plasma membrane to increase the cellular response to RAGE ligands, consequently exacerbating inflammation. Our study also showed that the loss of RAGE or EGFR expression by adoptive transfer of macrophages, blocking the function of RAGE with a neutralizing antibody, or pharmacological inhibition of EGFR activation in macrophages could protect against trauma- or stroke-induced remote lung injury. Therefore, our study revealed that targeting the RAGE-EGFR signaling pathway in tissue-resident macrophages is a potential therapeutic approach for treating secondary complications of sterile damage.

Hydrogen gas treatment improves survival in a rat model of crush syndrome by ameliorating rhabdomyolysis

Objectives

Crush syndrome (CS) is characterized by a systemic manifestation of traumatic rhabdomyolysis, leading to multiple organ dysfunction and death. Ischemia-reperfusion (IR) injury is commonly responsible for systemic response. Extending studies have shown that hydrogen gas treatment ameliorated IR injury in numerous experimental models; however, its effect on CS has not been well examined. This study aimed to investigate the effects of hydrogen gas inhalation following crush injury in an experimental model of CS.

Methods

Male Sprague-Dawley rats were subjected to experimental CS by applying a total of 3.0 kg weight to both hindlimb under general anesthesia for 6 h. Immediately after decompression, the animals were randomly placed in a gas chamber filled with either air or 1.3% hydrogen gas. Animals were sacrificed 18 h or 24 h following gas exposure for non-survival studies or for survival study, respectively.

Results

The rats with hydrogen treatment ( n = 6) had a higher 24-h survival than the rats with air treatment ( n = 9) (100% vs. 44%, p = 0.035). Lactate concentrations (2.9 ± 0.2 vs. 2.2 ± 0.2 mmol/L, p = 0.040) and creatine kinase (34,178 ± 13,580 vs. 5005 ± 842 IU/L, p = 0.016) were lower in the hydrogen group compared with the air group 18 h after decompression ( n = 4 in the air group, and n = 5 in the H2 group). Histological analysis revealed that the damage to the rectus femoris muscle and kidney appeared to be ameliorated by hydrogen treatment.

Conclusion

Hydrogen gas inhalation may be a promising therapeutic approach in the treatment of CS.

RAGE inhibitor TTP488 (Azeliragon) suppresses metastasis in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic cancer subtype, which is generally untreatable once it metastasizes. We hypothesized that interfering with the Receptor for Advanced Glycation End-products (RAGE) signaling with the small molecule RAGE inhibitors (TTP488/Azeliragon and FPS-ZM1) would impair TNBC metastasis and impair fundamental mechanisms underlying tumor progression and metastasis. Both TTP488 and FPS-ZM1 impaired spontaneous and experimental metastasis of TNBC models, with TTP488 reducing metastasis to a greater degree than FPS-ZM1. Transcriptomic analysis of primary xenograft tumor and metastatic tissue revealed high concordance in gene and protein changes with both drugs, with TTP488 showing greater potency against metastatic driver pathways. Phenotypic validation of transcriptomic analysis by functional cell assays revealed that RAGE inhibition impaired TNBC cell adhesion to multiple extracellular matrix proteins (including collagens, laminins, and fibronectin), migration, and invasion. Neither RAGE inhibitor impaired cellular viability, proliferation, or cell cycle in vitro. Proteomic analysis of serum from tumor-bearing mice revealed RAGE inhibition affected metastatic driver mechanisms, including multiple cytokines and growth factors. Further mechanistic studies by phospho-proteomic analysis of tumors revealed RAGE inhibition led to decreased signaling through critical BC metastatic driver mechanisms, including Pyk2, STAT3, and Akt. These results show that TTP488 impairs metastasis of TNBC and further clarifies the signaling and cellular mechanisms through which RAGE mediates metastasis. Importantly, as TTP488 displays a favorable safety profile in human studies, our study provides the rationale for evaluating TTP488 in clinical trials to treat or prevent metastatic TNBC.

Beyond the Alveolar Epithelium: Plasma Soluble Receptor for Advanced Glycation End Products Is Associated With Oxygenation Impairment, Mortality, and Extrapulmonary Organ Failure in Children With Acute Respiratory Distress Syndrome

OBJECTIVES

Soluble receptor for advanced glycation end products is a known plasma marker of alveolar epithelial injury. However, RAGE is also expressed on cell types beyond the lung, and its activation leads to up-regulation of pro-inflammatory mediators. We sought to examine the relationship between plasma soluble receptor for advanced glycation end products and primary pulmonary dysfunction, extrapulmonary organ dysfunction, and mortality in pediatric acute respiratory distress syndrome patients at two early time points following acute respiratory distress syndrome diagnosis and compare these results to plasma surfactant protein-D, a marker of pure alveolar epithelial injury.

DESIGN

Prospective observational study.

SETTING

Five academic PICUs.

PATIENTS

Two hundred fifty-eight pediatric patients 30 days to 18 years old meeting Berlin Criteria for acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma was collected for soluble receptor for advanced glycation end products and surfactant protein-D measurements within 24 hours (day 1) and 48 to 72 hours (day 3) after acute respiratory distress syndrome diagnosis. Similar to surfactant protein-D, plasma soluble receptor for advanced glycation end products was associated with a higher oxygenation index (p < 0.01) and worse lung injury score (p < 0.001) at the time of acute respiratory distress syndrome diagnosis. However, unlike surfactant protein-D, plasma soluble receptor for advanced glycation end products was associated with worse extrapulmonary Pediatric Logistic Organ Dysfunction score during ICU stay (day 3; p < 0.01) and positively correlated with plasma levels of interleukin-6 (p < 0.01), tumor necrosis factor-α (p < 0.01), and angiopoietin-2 (p < 0.01). Among children with indirect lung injury, plasma soluble receptor for advanced glycation end products was associated with mortality independent of age, sex, race, cancer/bone marrow transplant, and Pediatric Risk of Mortality score (day 3; odds ratio, 3.14; 95% CI, 1.46-6.75; p < 0.01).

CONCLUSIONS

Unlike surfactant protein-D, which is primarily localized to the alveolar epithelium plasma soluble receptor for advanced glycation end products is systemically expressed and correlates with markers of inflammation, extrapulmonary multiple organ dysfunction, and death in pediatric acute respiratory distress syndrome with indirect lung injury. This suggests that unlike surfactant protein-D, soluble receptor for advanced glycation end products is a multifaceted marker of alveolar injury and increased inflammation and that receptor for advanced glycation end products activation may contribute to the pathogenesis of multiple organ failure among children with indirect acute respiratory distress syndrome.

On-Site Laser Photobiomodulation Treatment of Crushed Muscle Due to Prolonged Pressure in Rats

BACKGROUND AND OBJECTIVES

Crush injuries and prolonged pressure on muscles lead to bruises and sprains and, in most of the cases, cause distraction of the muscle and release of particles into the blood stream, causing renal and systemic complications in severe cases. Laser photobiomodulation treatment (i.e., laser phototherapy) is a method suggested to decrease the pressure damage in the first 24-48 hours after muscle injury, allowing a faster and more complete physical rehabilitation. We studied the efficacy of non-invasive laser photobiomodulation treatment as an on-site treatment for crush-injured gastrocnemius muscles, developing a moderate muscle crush injury model and aiming at decreasing damage extent while regaining physical competence faster.

STUDY DESIGN/MATERIALS AND METHODS

Muscle crush injury was performed on 30 female Wistar rats using direct pressure for 10 minutes on the gastrocnemius muscle in both left and right hindlimbs. Immediately after the injury, only the left hindlimb were irradiated for 16 minutes (with 780 nm laser with a power of 250 mW, the energy at the target was 240 J, and the fluence was 1019 J/cm² ) for 1, 3, or 7 consecutive days, and sacrificed accordingly. During the follow-up period, 1, 3, or 7 days, both gastrocnemius muscles (of the treated and untreated hindlimbs) were evaluated for electrophysiology and functionality.

RESULTS

The laser photobiomodulation treatment showed a significant electrophysiological and functional recovery of the gastrocnemius muscle during the first 3 days after injury, in comparison with the untreated hindlimb.

CONCLUSIONS

These preliminary results are promising, showing a significant effect of the laser photobiomodulation treatment during the first 3 days after the induction of the muscle crush injury, which is the most critical period in the clinical aspect. These findings suggest a therapeutic approach, which may help restore the muscle after crush injury.

Emerging medical therapies in crush syndrome - progress report from basic sciences and potential future avenues

Crush injury is a disease that is commonly found in victims of earthquakes, debris flows, mine disasters, explosions, terrorist attacks, local wars, and other accidents. The complications that arise due to the crush injury inflicted on victims give rise to crush syndrome (CS). If not treated in time, the mortality rate of CS is very high. The most important measure that can be taken to reduce mortality in such situations is to immediately start treatment. However, the traditional treatment methods such as fluid resuscitation, diuresis, and hemodialysis are not feasible enough to be carried out at the disaster scene. So there is a need for developing new treatments that are efficient and convenient. Because it is difficult to diagnose in the disaster area and reach the treatment equipment and treat on time. It has become a new research needs to be directed into identifying new medical treatment targets and methods using the etiology and pathophysiological mechanisms of CS. In recent years, a large number of new anti-oxidant and anti-inflammatory drug therapies have been shown to be highly efficacious in CS rat/mouse models. Some of them are expected to become specific drugs for the emergency treatment of a large number of patients who may develop CS in the aftermath of earthquakes, wars, and other disasters in the future. Hence, we have reviewed the latest research on the medical therapy of CS as a source for anyone wishing to pursue research in this direction.

Targeting RAGE to prevent SARS-CoV-2-mediated multiple organ failure: Hypotheses and perspectives

A novel infectious disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was detected in December 2019 and declared as a global pandemic by the World Health. Approximately 15% of patients with COVID-19 progress to severe pneumonia and eventually develop acute respiratory distress syndrome (ARDS), septic shock and/or multiple organ failure with high morbidity and mortality. Evidence points towards a determinant pathogenic role of members of the renin-angiotensin system (RAS) in mediating the susceptibility, infection, inflammatory response and parenchymal injury in lungs and other organs of COVID-19 patients. The receptor for advanced glycation end-products (RAGE), a member of the immunoglobulin superfamily, has important roles in pulmonary pathological states, including fibrosis, pneumonia and ARDS. RAGE overexpression/hyperactivation is essential to the deleterious effects of RAS in several pathological processes, including hypertension, chronic kidney and cardiovascular diseases, and diabetes, all of which are major comorbidities of SARS-CoV-2 infection. We propose RAGE as an additional molecular target in COVID-19 patients for ameliorating the multi-organ pathology induced by the virus and improving survival, also in the perspective of future infections by other coronaviruses.

Activation of RAGE-dependent endoplasmic reticulum stress associates with exacerbated postmyocardial infarction ventricular arrhythmias in diabetes

Association between receptor for advanced glycation end products (RAGE) and postmyocardial infarction (MI) ventricular arrhythmias (VAs) in diabetes was investigated. Correlation between premature ventricular contractions (PVCs) and serum advanced glycation end products (AGEs) content was analyzed in a cohort consisting of 101 patients with ST-segment elevated MI (STEMI). MI diabetic rats were treated with anti-receptor for AGE (RAGE) antibody. Electrocardiography was used to record VAs. Myocytes were isolated from adjacent area around infracted region. Immunofluorescent stains were used to evaluate the association between FKBP12.6 (FK506-bindingprotein 12.6) and ryanodine receptor 2 (RyR2). Calcium sparks were evaluated by confocal microscope. Protein expression and phosphorylation were assessed by Western blotting. Calcineurin (CaN) enzymatic activity and RyR2 channel activity were also determined. In the cohort study, significantly increased amount of PVC was found in STEMI patients with diabetes (P < 0.05). Serum AGE concentration was significantly positively correlated with PVC amount in patients with STEMI (r = 0.416, P < 0.001). Multivariate analysis showed that serum AGE concentration was independently and positively related to frequent PVCs (adjusted hazard ratio, 1.86; 95% CI, 1.09-3.18, P = 0.022). In the animal study, increased glucose-regulated protein 78 (GRP78) expression, protein kinase RNA-like ER kinase (PERK) phosphorylation, CaN enzymatic activity, FKBP12.6-RyR2 disassociation, RyR2 channel opening, and endoplasmic reticulum (ER) calcium releasing were found in diabetic MI animals, which were attenuated by anti-RAGE antibody treatment. This RAGE blocking also significantly lowered the VA amount in diabetic MI animals. Activation of RAGE-dependent ER stress-mediated PERK/CaN/RyR2 signaling participated in post-MI VAs in diabetes.NEW & NOTEWORTHY In this study, we proposed a possible mechanism interpreting the clinical scenario that after myocardial infarction (MI) patients were more vulnerable to ventricular arrhythmias (VAs) when complicated with diabetes. A cohort study revealed that advanced glycation end products (AGEs) accumulated in patients with diabetes and closely associated post-MI VAs. In vivo and in vitro studies indicated that receptor for AGEs (RAGE)-dependent endoplasmic reticulum (ER) stress protein kinase RNA-like ER kinase (PERK) pathway triggered VAs, via ER calcium releasing, through calcineurin/RyR2 mechanism.

β1-Blocker improves survival and ventricular remodelling in rats with lethal crush injury

BACKGROUND

Crush injury/crush syndrome (CI/CS) is the second most common cause of death during earthquakes. Most studies of CI/CS have mainly focused on kidney injury after decompression. Few studies have focused on myocardial injury caused by crush injury and its potential mechanisms.

METHODS

We first verified cardiomyocyte injury during compression in rats with a crush injury. The survival rate, electrocardiographic results, histological results, catecholamine changes and cardiac β1-AR expression were evaluated. Next, we explored the effects of pretreatment with a selective β1-blocker (bisoprolol) with or without fluid resuscitation on rats with a crush injury. In addition to evaluating the survival rates, biochemical and histological analyses and echocardiographic measurements were also performed.

RESULTS

Reduced heart rates, elevated ST segments, and tall-peaked T waves were observed in the rats with a crush injury. The changes in the myocardial enzymes and pathological results demonstrated that myocardial damage occurred during compression in rats with a crush injury. The levels of the catecholamine norepinephrine in both the serum and myocardial tissue were elevated during compression. Pretreatment with a selective β1-blocker combined with fluid resuscitation significantly improved the survival rates of the rats with lethal crush injury. The myocardial enzymes and pathological results showed that the combined therapy decreased myocardial damage. The echocardiography measurements showed that the rats that received the combined therapy exhibited decreased left ventricular mass (LVM), left ventricular volume at end-systole (LVVs) and left ventricular internal diameter (LVID) compared with the rats with a crush injury.

CONCLUSIONS

Our findings demonstrated the presence of myocardial injury in the early stage of compression in rats with a crush injury. Pretreatment with a β1-blocker (bisoprolol) with fluid resuscitation significantly reduced mortality, decreased myocardial tissue damage, and improved ventricular remodelling in rats with a lethal crush injury.

Targeting the receptor for advanced glycation end products (RAGE) in type 1 diabetes

Type 1 diabetes (T1D) is one of the most common chronic diseases manifesting in early life, with the prevalence increasing worldwide at a rate of approximately 3% per annum. The prolonged hyperglycaemia characteristic of T1D upregulates the receptor for advanced glycation end products (RAGE) and accelerates the formation of RAGE ligands, including advanced glycation end products, high-mobility group protein B1, S100 calcium-binding proteins, and amyloid-beta. Interestingly, changes in the expression of RAGE and these ligands are evident in patients before the onset of T1D. RAGE signals via various proinflammatory cascades, resulting in the production of reactive oxygen species and cytokines. A large number of proinflammatory ligands that can signal via RAGE have been implicated in several chronic diseases, including T1D. Therefore, it is unsurprising that RAGE has become a potential therapeutic target for the treatment and prevention of disease. In this review, we will explore how RAGE might be targeted to prevent the development of T1D.

Surfen-mediated blockade of extratumoral chondroitin sulfate glycosaminoglycans inhibits glioblastoma invasion

Invasive spread of glioblastoma (GBM) is linked to changes in chondroitin sulfate (CS) proteoglycan (CSPG)-associated sulfated glycosaminoglycans (GAGs) that are selectively up-regulated in the tumor microenvironment (TME). We hypothesized that inhibiting CS-GAG signaling in the TME would stem GBM invasion. Rat F98 GBM cells demonstrated enhanced preferential cell invasion into oversulfated 3-dimensional composite of CS-A and CS-E [4- and 4,6-sulfated CS-GAG (COMP)] matrices compared with monosulfated (4-sulfated) and unsulfated hyaluronic acid matrices in microfluidics-based choice assays, which is likely influenced by differential GAG receptor binding specificities. Both F98 and human patient-derived glioma stem cells (GSCs) demonstrated a high degree of colocalization of the GSC marker CD133 and CSPGs. The small molecule sulfated GAG antagonist bis-2-methyl-4-amino-quinolyl-6-carbamide (surfen) reduced invasion and focal adhesions in F98 cells encapsulated in COMP matrices and blocked CD133 and antichondroitin sulfate antibody (CS-56) detection of respective antigens in F98 cells and human GSCs. Surfen-treated F98 cells down-regulated CSPG-binding receptor transcripts and protein, as well as total and activated ERK and protein kinase B. Lastly, rats induced with frontal lobe tumors and treated with a single intratumoral dose of surfen demonstrated reduced tumor burden and spread compared with untreated controls. These results present a first demonstration of surfen as an inhibitor of sulfated GAG signaling to stem GBM invasion.-Logun, M. T., Wynens, K. E., Simchick, G., Zhao, W., Mao, L., Zhao, Q., Mukherjee, S., Brat, D. J., Karumbaiah, L. Surfen-mediated blockade of extratumoral chondroitin sulfate glycosaminoglycans inhibits glioblastoma invasion.

The RAGE signaling pathway is involved in intestinal inflammation and represents a promising therapeutic target for Inflammatory Bowel Diseases

Inflammatory Bowel Diseases (IBD) are chronic inflammatory conditions of the intestinal tract. IBD are believed to result from an inappropriate immune response against the intestinal flora in genetically predisposed patients. The precise etiology of these diseases is not fully understood, therefore treatments rely on the dampening of symptoms, essentially inflammation, rather than on the cure of the disease. Despite the availability of biologics, such as anti-TNF antibodies, some patients remain in therapeutic failure and new treatments are thus needed. The multiligand receptor for advanced glycation end-products (RAGE) is a pattern recognition receptor implicated in inflammatory reactions and immune system activation. Here, we investigated the role of RAGE in intestinal inflammation and its potential as a therapeutic target in IBD. We showed that RAGE was upregulated in inflamed tissues from IBD patients compared to controls. Rage^-/- mice were less susceptible to intestinal and colonic inflammation development than WT mice. WT mice treated with the RAGE-specific inhibitor FPS-ZM1 experienced less severe enteritis and colitis. We demonstrated that RAGE could induce intestinal inflammation by promoting oxidative stress and endothelial activation which were diminished by FPS-ZM1 treatment. Our results revealed the RAGE signaling pathway as a promising therapeutic target for IBD patients.