Induction of two independent immunological cell death signaling following hemoglobinuria -induced acute kidney injury: In vivo study

Bibliometric analysis of ferroptosis in acute kidney injury from 2014 to 2022

INTRODUCTION

Acute kidney injury (AKI) is a global disease with high morbidity and mortality. At present, the treatment of AKI still lacks targeted measures. Ferroptosis, a form of regulated cell death, plays an essential role in the initiation and progression of AKI. Current evidence proves that targeting ferroptosis is supposed to be a novel potential strategy to cure AKI. In this study, we aim to use bibliometric analysis to identify research trends and hotspots in the field of "ferroptosis in AKI".

METHODS

We chose the Science Citation Index Expanded (SCI-EXPANDED) index of the Web of Science Core Collection (WoSCC) as the source database for data retrieval. Data were retrieved from the WoSCC on May 24, 2022. Full records and cited references of all the documents in WoSCC were collected. The R software and the Online Analysis Platform of Literature Metrology were used for data analysis and visual analysis.

RESULTS

There were 120 documents on "ferroptosis in AKI" in the WOSCC from 2014 to 2022 (May 24, 2022). There was a clear upward trend each year in the number of documents published. According to WoS report, China, the United States, and Germany were the top three countries involved in this research area, the majority of publications were included in the subject area "Cell Biology". Technical University of Dresden contributed the most publications, followed by Central South University and University of Pittsburgh. The Journal of Cell Death and Disease had the highest H-index and contributed the most publications. Linkermann A authored 16 articles and had the highest H-index. Multifactorial analysis of the keywords show that the research field is divided into two clusters. The most contributing publications and the most cited publications were also determined by factorial analysis.

CONCLUSION

This bibliometric analysis provides a comprehensive analysis of research trends and hot spots on the topic of "ferroptosis in AKI". The study of ferroptosis-related AKI research remains in its early stages. There will be a dramatically increasing number of publications on this field. Further research should focus on exploring the mechanisms of crosstalk between ferroptosis and other programmed cell deaths, and improves clinical applications and therapeutic effects against AKI.

Isolation of the Anticoagulant and Procoagulant Fractions of the Venom of Iranian Endemic Echis carinatus

Background

The venom of Echis carinatus contains both procoagulant and anticoagulant components that can either promote or block the blood coagulation cascade, and some of these components affect platelet function in different ways.

Objectives

The present study focuses on setting up a procedure for the purification of crude venom and designing appropriate clotting tests in order to characterize the procoagulant and anticoagulant fractions of E. carinatus venom.

Methods

Chromatographic methods, including gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (HPLC), were applied for purifying these fractions. Coagulant activity testing, prothrombin time (PT), and activated partial thromboplastin time (APTT) were used to determine procoagulant and anticoagulant properties. For measuring molecular weight, 15% SDS-PAGE electrophoresis with a molecular weight standard ranging from 6.5 to 200 kDa was used.

Results

We obtained five fractions named F₁, F₂, F₃, F₄, and F₅. The F₁ and F₂ fractions showed procoagulant activity, and the F₅ fraction had anticoagulant activity. The molecular weight of F_2.4.2 from fraction F₂ and F_5.1 from fraction F₅ were analyzed by SDS-PAGE electrophoresis under the reducing condition. These factors were identified as a single protein band at the end of purification. The molecular weights of these purified fractions were estimated to be 7.5 kDa and 38 kDa for F_5.1(b) and F_2.4.2(b), respectively.

Conclusions

Our findings suggest an efficient and suitable procedure for the identification and purification of the procoagulant and anticoagulant factors of the venom of Iranian E. carinatus using the PT and APTT assays.

Role of Toll-like receptor 4 in intravascular hemolysis-mediated injury

Massive intravascular hemolysis is a common characteristic of several pathologies. It is associated with the release of large quantities of heme into the circulation, promoting injury in vulnerable organs, mainly kidney, liver, and spleen. Heme activates Toll-like receptor 4 (TLR4), a key regulator of the inflammatory response; however, the role of TLR4 in hemolysis and whether inhibition of this receptor may protect from heme-mediated injury are unknown. We induced intravascular hemolysis by injection of phenylhydrazine in wildtype and Tlr4-knockout mice. In this model, we analyzed physiological parameters, histological damage, inflammation and cell death in kidney, liver, and spleen. We also evaluated whether heme-mediated-inflammatory effects were prevented by TLR4 inhibition with the compound TAK-242, both in vivo and in vitro. Induction of massive hemolysis elicited acute kidney injury characterized by loss of renal function, morphological alterations of the tubular epithelium, cell death, and inflammation. These pathological effects were significantly ameliorated in the TLR4-deficient mice and in wildtype mice treated with TAK-242. In vitro studies showed that TAK-242 pretreatment reduced heme-mediated inflammation by inhibiting the TLR4/NF-κB (nuclear factor kappa B) axis. However, analysis in liver and spleen indicated that TLR4 deficiency did not protect against the toxic accumulation of heme in these organs. In conclusion, TLR4 is a key molecule involved in the renal inflammatory response triggered by massive intravascular hemolysis. TLR4 inhibition may be a potential therapeutic approach to prevent renal damage in patients suffering from hemolysis. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Correlation between coenzyme Q10 content and the nutrient sensors in AKI induced by Hemiscorpius lepturus envenomation

Introduction: Acute kidney injury (AKI) may have a negative effect on mitochondrial hemostasis and bioenergetics as well as coenzyme Q₁₀ (CoQ₁₀) content. PGC-1α, AMPK, sirtuin 1 (Sirt1), and Sirt3, as the key metabolic regulators under nutritional stress, stimulate energy production via mitochondrial biogenesis during AKI. However, no report is available on the relationship between CoQ₁₀ level and nutrient sensors in the pathophysiology of AKI caused by Hemiscorpius lepturus scorpion envenomation. Methods: Three doses of venoms (1, 5, and 10 mg/kg) were administered by subcutaneous (SC) injection to male albino mice. The animals were sacrificed 1 day or 7 days after administration of venom and their kidneys were collected to analyze gene expression involved in AKI, nutrient sensors, and apoptosis signaling activation by real-time polymerase chain reaction (PCR) and the measurement of CoQ₁₀ level using the High-performance liquid chromatography (HPLC) method. Results: The data indicated a significant decrease in CoQ₁₀ level after the administration of venom in 5 and 10 mg/kg. In addition, 1 day after the treatment, a significant over-expression of Sirt1 (5 and 10 mg/kg) was observed compared with normal mice. Overexpression of Sirt3 occurred 1 day and 7 days after treatment only at the dose of 5.0 mg/kg of venom. Furthermore, over-expression of AMPK as an important mitochondrial energetic sensor happened 1 day and 7 days after the injection of venom (5 mg/kg) (P < 0.01). The significant increase in the gene expression of caspase-9 and 3 after the injection of venom (5 and 10 mg/kg) confirmed the role of cell death signaling. Conclusion: The venom-induced energy-sensing pathways have a key role in gene expression of PGC-1α, AMPK, Sirt3, and CoQ₁₀ content after venom-induced AKI.

Ultrasensitive Graphene-Based Nanobiosensor for Rapid Detection of Hemoglobin in Undiluted Biofluids

Detection of hemoglobin (Hb), a critical part of the biological system that is responsible for oxygen transportation, is of great significance on clinical diagnosis of various diseases. Particularly, time-efficient Hb detection under nanomole levels has drawn much attention in recent years. Herein, we present a graphene field effect transistor (GFET)-based aptameric nanobiosensor for rapid detection of Hb in undiluted biofluids including serum and urine and for the first time use polyethylenimine (PEI), a kind of comparatively low-cost polymer consisting of numerous amino groups, which can be directly linked with the anchor molecule without any pretreatment as the graphene surface passivation agent. Experimental results indicate the PEI-modified graphene aptameric nanobiosensor can respond to the Hb concentration change in a few minutes (6-8 min) with estimated detection limits of 10.6 fM in 1× PBS, 14.2 fM in undiluted serum, and 11.9 fM in undiluted urine, respectively. Further, considering the potential use of our sensor for implantable and wearable applications, we also examine the sensing performance of the sensor fabricated on an ultrathin flexible polyethylene terephthalate (PET) substrate. The Hb detection results are almost invariable even after 100 cycles of cyclic extension by 120% or 100 cycles of bending with a radius of 1 mm. Hence, our sensor holds great potential for accurate monitoring of nanomole levels of Hb in clinical applications.

Acute kidney injury caused by venomous animals: inflammatory mechanisms

Either bites or stings of venomous animals comprise relevant public health problems in tropical countries. Acute kidney injury (AKI) induced by animal toxins is related to worse prognostic and outcomes. Being one the most important pathways to induce AKI following envenoming due to animal toxins, inflammation is an essential biological response that eliminates pathogenic bacteria and repairs tissue after injury. However, direct nephrotoxicity (i.e. apoptotic and necrotic mechanisms of toxins), pigmenturia (i.e. rhabdomyolysis and hemolysis), anaphylactic reactions, and coagulopathies could contribute to the renal injury. All these mechanisms are closely integrated, but inflammation is a distinct process. Hence, it is important to improve our understanding on inflammation mechanisms of these syndromes to provide a promising outlook to reduce morbidity and mortality. This literature review highlights the main scientific evidence of acute kidney injury induced by bites or stings from venomous animals and their inflammatory mechanisms. It included observational, cross-sectional, case-control and cohort human studies available up to December 2019. Descriptors were used according to Medical Subject Headings (MeSH), namely: “Acute kidney injury” or “Venom” and “Inflammation” on Medline/Pubmed and Google Scholar; “Kidney disease” or “Acute kidney injury” on Lilacs and SciELO. The present review evidenced that, among the described forms of renal inflammation, it can occur either directly or indirectly on renal cells by means of intravascular, systemic and endothelial hemolysis, activation of inflammatory pathway, as well as direct action of venom cytotoxic components on kidney structures.

Ferroptosis and Necroptosis in the Kidney

In the last decade, the role of apoptosis in the pathophysiology of acute kidney injury (AKI) and AKI to chronic kidney disease (CKD) progression has been revisited as our understanding of ferroptosis and necroptosis has emerged. A growing body of evidence, reviewed here, ascribes a central pathophysiological role for ferroptosis and necroptosis to AKI, nephron loss, and acute tubular necrosis. We will introduce concepts to the non-cell-autonomous manner of kidney tubular injury during ferroptosis, a phenomenon that we refer to as a "wave of death." We hypothesize that necroptosis might initiate cell death propagation through ferroptosis. The remaining necrotic debris requires effective removal processes to prevent a secondary inflammatory response, referred to as necroinflammation. Open questions include the differences in the immunogenicity of ferroptosis and necroptosis, and the specificity of necrostatins and ferrostatins to therapeutically target these processes to prevent AKI-to-CKD progression and end-stage renal disease.

The effects of Hemiscorpius lepturus induced-acute kidney injury on PGC-1α gene expression: From induction to suppression in mice

Hemiscorpius lepturus envenomation induces acute kidney injury (AKI) through hemoglubinoria and mitochondrial dysfunction. Mitochondria supports ATP production to promote the regulation of fluid and electrolyte balance. Mitochondrial homeostasis in different metabolic environments can be adjusted by overexpression of PGC-1α. High reactive oxygen species (ROS) production after H. lepturus envenomation and heme oxygenase-1 (HO-1) overexpression causes ATP depletion as well as mitochondrial homeostasis disruption, which lead to progression in renal diseases. The present study aims to evaluate the role of venom induced-AKI in modulating mitochondrial function in cell death and metabolic signaling associated with PPAR-α, PGC-1α, and Nrf-2 as the main transcription factors involved in metabolism. Based on the data, two significant events occurred after envenomation: reduction of gl glutathione level and overexpression of the cytoprotective enzyme HO-1. Apaoptosis induction is associated with a significant decrease in the transcription of PPAR-α, PGC-1α and Nrf-2 after administrating lethal dose of venom (10 mg/kg). Furthermore, at the lower doses of venom (1 and 5 mg/kg), with a significant recovery accompanied with PGC-1α upregulation occurs after AKI. As the findings indicate, PGC-1α has a key role in restoring the mitochondrial function at the recovery phase of mouse model of AKI, which highlights the PGC-1α as a therapeutic target for venom induced-AKI prevention and treatment.