Ethyl Pyruvate Directly Attenuates Active Secretion of HMGB1 in Proximal Tubular Cells via Induction of Heme Oxygenase-1

High mobility group box-1: a potential therapeutic target for allergic rhinitis

Allergic rhinitis (AR) is a prevalent chronic inflammatory disease of the nasal mucosa primarily characterized by symptoms, such as nasal itching, sneezing, runny nose, and nasal congestion. It has a high recurrence rate and low cure rate, with a lack of effective drugs for treatment. The current approach to management focuses on symptom control. High mobility group box-1 (HMGB1) is a highly conserved non-histone protein widely present in the nucleus of eukaryotes. It is recognized as a proinflammatory agent, and recent studies have demonstrated its close association with AR. Here, we will elaborate the role and mechanism of HMGB1 in AR, so as to reveal the potential value of HMGB1 in the occurrence and development of AR, and provide a new target for clinical research on the treatment of AR.

Tubular Epithelial Cell HMGB1 Promotes AKI-CKD Transition by Sensitizing Cycling Tubular Cells to Oxidative Stress: A Rationale for Targeting HMGB1 during AKI Recovery

SIGNIFICANCE STATEMENT

Cells undergoing necrosis release extracellular high mobility group box (HMGB)-1, which triggers sterile inflammation upon AKI in mice. Neither deletion of HMGB1 from tubular epithelial cells, nor HMGB1 antagonism with small molecules, affects initial ischemic tubular necrosis and immediate GFR loss upon unilateral ischemia/reperfusion injury (IRI). On the contrary, tubular cell-specific HMGB1 deficiency, and even late-onset pharmacological HMGB1 inhibition, increased functional and structural recovery from AKI, indicating that intracellular HMGB1 partially counters the effects of extracellular HMGB1. In vitro studies indicate that intracellular HMGB1 decreases resilience of tubular cells from prolonged ischemic stress, as in unilateral IRI. Intracellular HMGB1 is a potential target to enhance kidney regeneration and to improve long-term prognosis in AKI.

BACKGROUND

Late diagnosis is a hurdle for treatment of AKI, but targeting AKI-CKD transition may improve outcomes. High mobility group box-1 (HMGB1) is a nuclear regulator of transcription and a driver of necroinflammation in AKI. We hypothesized that HMGB1 would also modulate AKI-CKD transition in other ways.

METHODS

We conducted single-cell transcriptome analysis of human and mouse AKI and mouse in vivo and in vitro studies with tubular cell-specific depletion of Hmgb1 and HMGB1 antagonists.

RESULTS

HMGB1 was ubiquitously expressed in kidney cells. Preemptive HMGB1 antagonism with glycyrrhizic acid (Gly) and ethyl pyruvate (EP) did not affect postischemic AKI but attenuated AKI-CKD transition in a model of persistent kidney hypoxia. Consistently, tubular Hmgb1 depletion in Pax8 rtTA, TetO Cre, Hmgb1fl/fl mice did not protect from AKI, but from AKI-CKD transition. In vitro studies confirmed that absence of HMGB1 or HMGB1 inhibition with Gly and EP does not affect ischemic necrosis of growth-arrested differentiated tubular cells but increased the resilience of cycling tubular cells that survived the acute injury to oxidative stress. This effect persisted when neutralizing extracellular HMGB1 with 2G7. Consistently, late-onset HMGB1 blockade with EP started after the peak of ischemic AKI in mice prevented AKI-CKD transition, even when 2G7 blocked extracellular HMGB1.

CONCLUSION

Treatment of AKI could become feasible when ( 1 ) focusing on long-term outcomes of AKI; ( 2 ) targeting AKI-CKD transition with drugs initiated after the AKI peak; and ( 3 ) targeting with drugs that block HMGB1 in intracellular and extracellular compartments.

HMGB1 is a Potential and Challenging Therapeutic Target for Parkinson's Disease

Parkinson's disease (PD) is one of the most common degenerative diseases of the human nervous system and has a wide range of serious impacts on human health and quality of life. Recently, research targeting high mobility group box 1 (HMGB1) in PD has emerged, and a variety of laboratory methods for inhibiting HMGB1 have achieved good results to a certain extent. However, given that HMGB1 undergoes a variety of intracellular modifications and three different forms of extracellular redox, the possible roles of these forms in PD are likely to be different. General inhibition of all forms of HMGB1 is obviously not ideal and has become one of the biggest obstacles in the clinical application of targeting HMGB1. In this review, pure mechanistic research of HMGB1 and in vivo research targeting HMGB1 were combined, the effects of HMGB1 on neurons and immune cell responses in PD are discussed in detail, and the problems that need to be focused on in the future are addressed.

Toll-like receptors 2 and 4 stress signaling and sodium-glucose cotransporter-2 in kidney disease

Kidney disease is the 6th fastest-growing cause of death and a serious global health concern that urges effective therapeutic options. The inflammatory response is an initial reaction from immune and parenchymal cells in kidney diseases. Toll-like receptors (TLR) 2 and 4 are highly expressed by various kidney cells and respond to 'signaling danger' proteins, such as high mobility group box binding protein 1 (HMGB1) and prompt the progression of kidney disease by releasing inflammatory mediators. Burgeoning reports suggest that both SGLT2 and ER stress elevates TLR2/4 signaling via different axis. Moreover, SGLT2 signaling aggravates inflammation under the disease condition by promoting the NLR family pyrin domain-containing three inflammasomes and ER stress. Intriguingly, TLR2/4 downstream adaptors activate ER stress regulators. The above-discussed interactions imply that TLR2/4 does more than immune response during kidney disease. Here, we discuss in detail evidence of the roles and regulation of TLR2/4 in the context of a relationship between ER stress and SGLT2. Also, we highlighted different preclinical studies of SGLT2 inhibitors against TLR2/4 signaling in various kidney diseases. Moreover, we discuss the observational and interventional evidence about the relation between TLR2/4, ER stress, and SGLT2, which may represent the TLR2/4 as a potential therapeutic target for kidney disease.

HMGB1 in nervous system diseases: A common biomarker and potential therapeutic target

High-mobility group box-1 (HMGB1) is a nuclear protein associated with early inflammatory changes upon extracellular secretion expressed in various cells, including neurons and microglia. With the progress of research, neuroinflammation is believed to be involved in the pathogenesis of neurological diseases such as Parkinson's, epilepsy, and autism. As a key promoter of neuroinflammation, HMGB1 is thought to be involved in the pathogenesis of Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, and amyotrophic lateral sclerosis. However, in the clinic, HMGB1 has not been described as a biomarker for the above-mentioned diseases. However, the current preclinical research results show that HMGB1 antagonists have positive significance in the treatment of Parkinson's disease, stroke, traumatic brain injury, epilepsy, and other diseases. This review discusses the possible mechanisms by which HMGB1 mediates Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, amyotrophic lateral sclerosis, and the potential of HMGB1 as a biomarker for these diseases. Future research needs to further explore the underlying molecular mechanisms and clinical translation.

Bladder Oxidative Stress and HMGB1 Release Contribute to PAR4-Mediated Bladder Pain in Mice

Activation of intravesical PAR4 receptors leads to bladder hyperalgesia (BHA) through release of urothelial macrophage migration inhibitory factor (MIF) and urothelial high mobility group box-1 (HMGB1). MIF deficiency and/or MIF antagonism at the bladder block BHA in mice yet the mechanisms are not clear. Since oxidative stress and ERK phosphorylation are involved in MIF signaling we hypothesized that oxidative stress and/or ERK signaling, activated by MIF release, promote intravesical HMGB1 release to induce BHA. We induced BHA by intravesical PAR4 infusion in female C57BL/6 mice. Mechanical sensitivity was evaluated by measuring abdominal von Frey (VF) 50% thresholds before (baseline) and 24 h post-infusion. Intravesical pre-treatment (10 min infusion prior to PAR4) with N-acetylcysteine amide (NACA; reactive-oxygen species scavenger; 3 mg in 50 μl), FR180204 (selective ERK1/2 inhibitor; 200 μg in 50 μl), ethyl pyruvate (EP; HMGB1 release inhibitor; 600 μg in 50 μl), or diluent controls (50 μl) tested the effects of pre-treatment on PAR4-induced BHA. Intravesical fluid was collected after each treatment and HMGB1 concentration was measured using ELISA. Awake micturition parameters (volume and frequency) were assessed at the end of the experiments. Bladders were collected and examined for histological signs of edema and inflammation. Pre-treatment with PBS followed by PAR4 induced BHA in mice but PBS followed by scrambled peptide did not. Pre-treatment with NACA or EP partially blocked PAR4-induced BHA while FR180204 had no effect. A significant correlation between intravesical HMGB1 levels and 50% VF thresholds was observed. All PAR4 treated groups had increased levels of HMGB1 in the intravesical fluid compared to PBS-Scrambled group although not statistically significant. No significant effects were noted on awake micturition volume, micturition frequency or histological evidence of bladder edema or inflammation. Our results show that intravesical antagonism of bladder reactive-oxygen species accumulation was effective in reducing PAR4-induced bladder pain. The correlation between intravesical levels of HMGB1 and bladder pain indicates that released HMGB1 is pivotal to bladder pain. Thus, modulating events in the MIF signaling cascade triggered by PAR4 activation (including bladder oxidative stress and HMGB1 release) warrant further investigation as possible therapeutic strategies.

Immunomodulatory Effects of Heme Oxygenase-1 in Kidney Disease

Kidney disease is a general term for heterogeneous damage that affects the function and the structure of the kidneys. The rising incidence of kidney diseases represents a considerable burden on the healthcare system, so the development of new drugs and the identification of novel therapeutic targets are urgently needed. The pathophysiology of kidney diseases is complex and involves multiple processes, including inflammation, autophagy, cell-cycle progression, and oxidative stress. Heme oxygenase-1 (HO-1), an enzyme involved in the process of heme degradation, has attracted widespread attention in recent years due to its cytoprotective properties. As an enzyme with known anti-oxidative functions, HO-1 plays an indispensable role in the regulation of oxidative stress and is involved in the pathogenesis of several kidney diseases. Moreover, current studies have revealed that HO-1 can affect cell proliferation, cell maturation, and other metabolic processes, thereby altering the function of immune cells. Many strategies, such as the administration of HO-1-overexpressing macrophages, use of phytochemicals, and carbon monoxide-based therapies, have been developed to target HO-1 in a variety of nephropathological animal models, indicating that HO-1 is a promising protein for the treatment of kidney diseases. Here, we briefly review the effects of HO-1 induction on specific immune cell populations with the aim of exploring the potential therapeutic roles of HO-1 and designing HO-1-based therapeutic strategies for the treatment of kidney diseases.

Ethyl pyruvate: A newly discovered compound against ischemia-reperfusion injury in multiple organs

Ischemia-reperfusion injury (IRI) is a process whereby an initial ischemia injury and subsequent recovery of blood flow, which leads to the propagation of an innate immune response and the changes of structural and functional of multiple organs. Therefore, IRI is considered to be a great challenge in clinical treatment such as organ transplantation or coronary angioplasty. In recent years, ethyl pyruvate (EP), a derivative of pyruvate, has received great attention because of its stability and low toxicity. Previous studies have proved that EP has various pharmacological activities, including anti-inflammation, anti-oxidative stress, anti-apoptosis, and anti-fibrosis. Compelling evidence has indicated EP plays a beneficial role in a variety of acute injury models, such as brain IRI, myocardial IRI, renal IRI, and hepatic IRI. Moreover, EP can not only effectively inhibit multiple IRI-induced pathological processes, but also improve the structural and functional lesion of tissues and organs. In this study, we review the recent progress in the research on EP and discuss their implications for a better understanding of multiple organ IRI, and the prospects of targeting the EP for therapeutic intervention.

The Immune Tolerance Role of the HMGB1-RAGE Axis

The disruption of the immune tolerance induces autoimmunity such as systemic lupus erythematosus and vasculitis. A chromatin-binding non-histone protein, high mobility group box 1 (HMGB1), is released from the nucleus to the extracellular milieu in particular environments such as autoimmunity, sepsis and hypoxia. Extracellular HMGB1 engages pattern recognition receptors, including Toll-like receptors (TLRs) and the receptor for advanced glycation endproducts (RAGE). While the HMGB1-RAGE axis drives inflammation in various diseases, recent studies also focus on the anti-inflammatory effects of HMGB1 and RAGE. This review discusses current perspectives on HMGB1 and RAGE’s roles in controlling inflammation and immune tolerance. We also suggest how RAGE heterodimers responding microenvironments functions in immune responses.

Integrating metabolomics and network pharmacology to explore Rhizoma Coptidis extracts against sepsis-associated acute kidney injury

Sepsis remains the most common cause of acute kidney injury (AKI) in critically ill patients, increasing the risk of in-hospital and long-term death. Rhizoma Coptidis (RC), a classical traditional Chinese herb, exhibits anti-inflammatory and antioxidant properties in various diseases including sepsis. This study aimed to investigate the protective effects of RC extracts (RCE) against sepsis-associated acute kidney injury (SA-AKI) and explore the underlying mechanisms with metabolomics-based network pharmacology. The results showed that RCE improved renal function and histological injury and decreased reactive oxygen species (ROS) production in SA-AKI. Using ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS), 25 differential metabolites were identified that had a close connection with the pathological processes of SA-AKI and the effects of RCE. Afterward, a compound-metabolite-target-disease network was constructed and 17 overlapping target proteins of the components of RCE, the differential metabolites, and the disease-related genes were discovered. Among these overlapping target proteins, RCE increased the nuclear translocation of nuclear factor-erythroid 2-related factor-2 (Nrf2), the protein expression of heme oxygenase-1 (HO-1), the mRNA expression of peroxisome proliferator activated receptor α (PPARα) and reduced nitric oxide synthase 2 (NOS2) activity. In addition, molecular docking revealed that both berberine and quercetin could bond with NOS2 and PPARα, respectively. Therefore, RCE demonstrated protective effects for SA-AKI through the regulation of metabolism and different signaling pathways.

New insights into the role of heme oxygenase-1 in acute kidney injury

Acute kidney injury (AKI) is attended by injury-related biomarkers appearing in the urine and serum, decreased urine output, and impaired glomerular filtration rate. AKI causes increased morbidity and mortality and can progress to chronic kidney disease and end-stage kidney failure. AKI is without specific therapies and is managed by supported care. Heme oxygenase-1 (HO-1) is a cytoprotective, inducible enzyme that degrades toxic free heme released from destabilized heme proteins and, during this process, releases beneficial by-products such as carbon monoxide and biliverdin/bilirubin and promotes ferritin synthesis. HO-1 induction protects against assorted renal insults as demonstrated by in vitro and preclinical models. This review summarizes the advances in understanding of the protection conferred by HO-1 in AKI, how HO-1 can be induced including via its transcription factor Nrf2, and HO-1 induction as a therapeutic strategy.

Tim-3 deteriorates neuroinflammatory and neurocyte apoptosis after subarachnoid hemorrhage through the Nrf2/HMGB1 signaling pathway in rats

Inflammation is known to play an important role in early brain injury (EBI) after subarachnoid hemorrhage (SAH). T cell immunoglobulin and mucin domain-3 (Tim-3) has emerged as a critical regulator of adaptive and innate immune responses, and has been identified to play a vital role in certain inflammatory diseases; The present study explored the effect of Tim-3 on inflammatory responses and detailed mechanism in EBI following SAH. We investigated the effects of Tim-3 on SAH models established by endovascular puncture method in Sprague–Dawley rats. The present studies revealed that SAH induced a significant inflammatory response and significantly increased Tim-3 expression. Tim-3-AAV administration aggravated neurocyte apoptosis, brain edema, blood-brain barrier permeability, and neurological dysfunction; significantly inhibited Nrf2 expression; and increased HMGB1 expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor alpha, interleukin (IL)-1 beta, IL-17, and IL-18. However, Tim-3 siRNA or NK252 administration abolished the pro-inflammatory effects of Tim-3. Our results indicate a function for Tim-3 as a molecular player that links neuroinflammation and brain damage after SAH. We reveal that Tim-3 overexpression deteriorates neuroinflammatory and neurocyte apoptosis after subarachnoid hemorrhage through the Nrf2/HMGB1 signaling pathway in rats.

Nrf-2 as a therapeutic target in acute kidney injury

Multifaceted cellular pathways exhibit a crucial role in the preservation of homeostasis at the molecular, cellular, and organism levels. One of the most important of these protective cascades is Nuclear factor E2-related factor (Nrf-2) that regulates the expression of several genes responsible for cellular detoxification, antioxidant function, anti-inflammation, drug/xenobiotic transportation, and stress-related factors. A growing body of evidence provides information regarding the protective role of Nrf-2 against a number of kidney diseases. Acute kidney injury (AKI) is a substantial clinical problem that causes a huge social burden. In the kidneys, Nrf-2 exerts a dynamic role in improving the injury triggered by inflammation and oxidative stress. Understanding of the exact molecular mechanisms underlying AKI is vital in order to determine the equilibrium between renal adaptation and malfunction and thus reduce disease progression. This review highlights the role of Nrf-2 targeting against AKI and provides evidence that targeting Nrf-2 to prevail oxidative damage and its consequences might exhibit protective effects in kidney diseases.

Honokiol Protects the Kidney from Renal Ischemia and Reperfusion Injury by Upregulating the Glutathione Biosynthetic Enzymes

Glutathione (GSH) is an endogenous antioxidant found in plants, animals, fungi, and some microorganisms that protects cells by neutralizing hydrogen peroxide. Honokiol, an active ingredient of Magnolia officinalis, is known for antioxidant, anti-inflammatory, and anti-bacterial properties. We investigated the protective mechanism of honokiol through regulating cellular GSH in renal proximal tubules against acute kidney injury (AKI). First, we measured cellular GSH levels and correlated them with the expression of GSH biosynthetic enzymes after honokiol treatment in human kidney-2 (HK-2) cells. Second, we used pharmacological inhibitors or siRNA-mediated gene silencing approach to determine the signaling pathway induced by honokiol. Third, the protective effect of honokiol via de novo GSH biosynthesis was investigated in renal ischemia-reperfusion (IR) mice. Honokiol significantly increased cellular GSH levels by upregulating the subunits of glutamate-cysteine ligase (Gcl)—Gclc and Gclm. These increases were mediated by activation of nuclear factor erythroid 2-related factor 2, via PI3K/Akt and protein kinase C signaling. Consistently, honokiol treatment reduced the plasma creatinine, tubular cell death, neutrophil infiltration and lipid peroxidation in IR mice and the effect was correlated with upregulation of Gclc and Gclm. Conclusively, honokiol may benefit to patients with AKI by increasing antioxidant GSH via transcriptional activation of the biosynthetic enzymes.

HMGB1 A box protects neurons by potently inhibiting both microglia and T cell-mediated inflammation in a mouse Parkinson's disease model

In the subacute Parkinson's disease (PD) mice model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), injection of HMGB1 competitive inhibitor protein HMGB1 A box and the ethyl pyruvate (EP) that inhibit the release of HMGB1 from cells restored the number of dopaminergic neurons and TH+ fibers in the SN and striatum. Our data show that A box up-regulated CD200-CD200R signal of microglia inhibited the activation of microglia mediated by HMGB1, and the production of TNF-α, IL-1β and IL-6 in vivo and in vitro mixed culture system. Microglia overexpressing CD200R produced less inflammatory chemokines and reduced the loss of TH+ neurons. In addition, HMGB1 A box decreased the level of CCL5 and significantly inhibited the infiltration of almost all T cells including Th17 and the proportion of Th17 in CD4+ T cells. In vitro MPP+ induced model and HMGB1-stimulated mesencephalic cell system activated microglia induced the differentiation of naïve T cells to Th17, and A box significantly inhibited this process. To sum up, our results show that HMGB1 A box targeting HMGB1, which effectively reduces the activation of microglia in MPTP PD model by restoring CD200-CD200R signal inhibit microglia mediated neuroinflammation and the differentiation of T cells to Th17.

HMGB1 in kidney diseases

High mobility group box 1 (HMGB1) is a highly conserved nucleoprotein involving in numerous biological processes, and well known to trigger immune responses as the damage-associated molecular pattern (DAMP) in the extracellular environment. The role of HMGB1 is distinct due to its multiple functions in different subcellular location. In the nucleus, HMGB1 acts as a chaperone to regulate DNA events including DNA replication, repair and nucleosome stability. While in the cytoplasm, it is engaged in regulating autophagy and apoptosis. A great deal of research has explored its function in the pathogenesis of renal diseases. This review mainly focuses on the role of HMGB1 and summarizes the pathway and treatment targeting HMGB1 in the various renal diseases which may open the windows of opportunities for the development of desirable therapeutic ends in these pathological conditions.

Preconditioning with rHMGB1 ameliorates lung ischemia-reperfusion injury by inhibiting alveolar macrophage pyroptosis via the Keap1/Nrf2/HO-1 signaling pathway

BACKGROUND

Lung ischemia-reperfusion injury (LIRI) is a complex pathophysiological process that can lead to poor patient outcomes. Inflammasome-dependent macrophage pyroptosis contributes to organ damage caused by ischemia/reperfusion injury. Oxidative stress and antioxidant enzymes also play an important role in LIRI. In this study, we conducted experiments to investigate whether and how preconditioning with rHMGB1 could ameliorate LIRI in a mouse model.

METHODS

Adult male BALB/c mice were anesthetized, the left hilus pulmonis was clamped, and reperfusion was performed. rHMGB1 was administered via intraperitoneal injection before anesthesia, and brusatol was given intraperitoneally every other day before surgery. We measured pathohistological lung tissue damage, wet/dry mass ratios of pulmonary tissue, and levels of inflammatory mediators to assess the extent of lung injury. Alveolar macrophage pyroptosis was evaluated by measuring release of lactate dehydrogenase, caspase-1 expression was assessed using flow cytometry, and gasdermin-D expression was analyzed using immunofluorescent staining. Levels of oxidative stress markers and antioxidant enzymes were also analyzed.

RESULTS

Preconditioning with rHMGB1 significantly ameliorated lung injury induced by ischemia-reperfusion, based on measurements of morphology, wet/dry mass ratios, as well as expression of IL-1β, IL-6, NF-κB, and HMGB1 in lung tissues. It also alleviated alveolar macrophage pyroptosis, reduced oxidative stress and restored the activity of antioxidant enzymes. These beneficial effects were mediated at least in part by the Keap1/Nrf2/HO-1 pathway, since they were reversed by the pathway inhibitor brusatol.

CONCLUSIONS

Preconditioning with rHMGB1 may protect against LIRI by suppressing alveolar macrophage pyroptosis. This appears to involve reduction of oxidative stress and promotion of antioxidant enzyme activity via the Keap1/Nrf2/HO-1 pathway.

High mobility group box 1 (HMGB1): a pivotal regulator of hematopoietic malignancies

High mobility group box 1 (HMGB1) is a nonhistone chromatin-associated protein that has been widely reported to play a pivotal role in the pathogenesis of hematopoietic malignancies. As a representative damage-associated molecular pattern (DAMP), HMGB1 normally exists inside cells but can be secreted into the extracellular environment through passive or active release. Extracellular HMGB1 binds with several different receptors and interactors to mediate the proliferation, differentiation, mobilization, and senescence of hematopoietic stem cells (HSCs). HMGB1 is also involved in the formation of the inflammatory bone marrow (BM) microenvironment by activating proinflammatory signaling pathways. Moreover, HMGB1-dependent autophagy induces chemotherapy resistance in leukemia and multiple myeloma. In this review, we systematically summarize the emerging roles of HMGB1 in carcinogenesis, progression, prognosis, and potential clinical applications in different hematopoietic malignancies. In summary, targeting the regulation of HMGB1 activity in HSCs and the BM microenvironment is highly beneficial in the diagnosis and treatment of various hematopoietic malignancies.

Urinary neutrophil gelatinase-associated lipocalin rapidly decreases in the first week after kidney transplantation

BACKGROUND

Recipient delayed graft function, which is defined as dialysis in the first week after transplantation, is one of the most common early complications after kidney transplantation. This study aimed to evaluate the daily changes in renal function-related biomarkers in the first week post-transplant.

METHODS

A total of 72 kidney transplant recipients were retrospectively included in this study. Clinical and laboratory data were collected daily during the first week post-transplant, including urinary concentrations of neutrophil gelatinase-associated lipocalin (NGAL), serum concentrations of NGAL, creatinine, urea nitrogen, uric acid (UA), β2-microglobulin, cystatin C, and estimated glomerular filtration rate (eGFR).

RESULTS

There were no significant differences in urea nitrogen (P = .375), UA (P = .090), and cystatin C (P = .691), while urinary NGAL (P < .0001), serum NGAL (P < .0001), creatinine (P < .0001), β2-microglobulin (P < .0001), and eGFR (P < .0001) were statistically significant in the first week post-transplant. In comparison with serum NGAL (P < .0001), creatinine (P < .0001), β2-microglobulin (P = .001), and eGFR (P = .001), the change ratios of urinary NGAL changed the most between day 1 and day 2 after renal transplantation, while the changing degree of urinary NGAL showed no significant difference compared with these indicators between day 1 and day 7 after kidney transplantation.

CONCLUSION

Urinary NGAL is a sensitive marker for indicating renal function. Urinary NGAL combined with other markers can be more helpful for evaluating renal function in the first week following kidney transplantation.

HMGB1 promoted P-glycoprotein at the blood-brain barrier in MCAO rats via TLR4/NF-κB signaling pathway

P-glycoprotein (P-gp) is located on the luminal surface of brain vascular endothelium and its status may determine the delivery of the agents into the brain tissues. Previous study showed that upregulation of P-gp at the blood-brain barrier (BBB) after ischemic stroke were mediated by nuclear factor-B (NF-kB) and tumour necrosis factor-α (TNF-α). Based on middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation (OGD) in co-culture of rat brain microvessel endothelial cells (rBMECs) and astrocytes system, the present data indicated that potentiated P-gp expression and activity in brain microvessels or rBMECs were associated with the increase in high-mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR4) and activation of NF-kB and that HMGB1 can release from nucleus to the cytoplasm in activated astrocytes, then into the medium. Moreover, changes in TLR4, TIR domain-containing adaptor protein (TIRAP), NF-kB and P-gp in rBMECs were attenuated by addition of 1 mM ethyl pyruvate (EP), 10 μM TAK-242 and 10 μM pyrrolidine dithiocarbamate (PDTC), respectively. These results demonstrated that HMGB1 promoted P-gp at the BBB after cerebral ischemia via TLR4/NF-κB signaling pathway.