Protective effects of the nuclear factor kappa B inhibitor pyrrolidine dithiocarbamate in bladder ischemia–reperfusion injury in rats

Cofilin-1 induces acute kidney injury via the promotion of endoplasmic reticulum stress-mediated ferroptosis

Ischemia-reperfusion injury (IRI) leads to acute kidney injury (AKI), which poses serious threat to public health and society. Many clinical studies were conducted to evaluate several biomarkers in AKI, among which Cofilin-1 remains to be a very promising one. To explore the potential mechanism of Cofilin-1 in AKI, we established an oxygen-glucose-deprivation (OGD)-induced AKI cell model. The overexpression and knock-down Cofilin-1 were used for gain- and loss-of-function. Pharmacological inhibitors were employed to study the related pathways. The results showed that Cofilin-1 was significantly upregulated in AKI cells, knocking down Cofilin-1 protected cells against the effect of OGD treatment and alleviated AKI phenotypes. Overexpression of Cofilin-1 might induce AKI by triggering ferroptosis, inhibiting NF-κB signaling or ER stress pathway attenuated Cofilin-1 induced lipid peroxidation and AKI. We also validated our findings in IRI-induced AKI mouse models in vivo. Our work elucidated that Cofilin-1 might induce AKI via promoting ER stress-mediated ferroptosis and argues it as a biomarker for early diagnosis of AKI. We also expect to offer novel insights on future therapeutic interventions.

Strategies for Improving Photodynamic Therapy Through Pharmacological Modulation of the Immediate Early Stress Response

Photodynamic therapy (PDT) is a minimally to noninvasive treatment modality that has emerged as a promising alternative to conventional cancer treatments. PDT induces hyperoxidative stress and disrupts cellular homeostasis in photosensitized cancer cells, resulting in cell death and ultimately removal of the tumor. However, various survival pathways can be activated in sublethally afflicted cancer cells following PDT. The acute stress response is one of the known survival pathways in PDT, which is activated by reactive oxygen species and signals via ASK-1 (directly) or via TNFR (indirectly). The acute stress response can activate various other survival pathways that may entail antioxidant, pro-inflammatory, angiogenic, and proteotoxic stress responses that culminate in the cancer cell's ability to cope with redox stress and oxidative damage. This review provides an overview of the immediate early stress response in the context of PDT, mechanisms of activation by PDT, and molecular intervention strategies aimed at inhibiting survival signaling and improving PDT outcome.

Ferroptosis: A Trigger of Proinflammatory State Progression to Immunogenicity in Necroinflammatory Disease

Until recently, necrosis is generally regarded as traumatic cell death due to mechanical shear stress or other physicochemical factors, while apoptosis is commonly thought to be programmed cell death, which is silent to immunological response. Actually, multiple modalities of cell death are programmed to maintain systematic immunity. Programmed necrosis, such as necrosis, pyroptosis, and ferroptosis, are inherently more immunogenic than apoptosis. Programmed necrosis leads to the release of inflammatory cytokines, defined as danger-associated molecular patterns (DAMPs), resulting in a necroinflammatory response, which can drive the proinflammatory state under certain biological circumstances. Ferroptosis as a newly discovered non-apoptotic form of cell death, is characterized by excessive lipid peroxidation and overload iron, which occurs in cancer, neurodegeneration, immune and inflammatory diseases, as well as ischemia/reperfusion (I/R) injury. It is triggered by a surplus of reactive oxygen species (ROS) induced in an imbalanced redox reaction due to the decrease in glutathione synthesis and inaction of enzyme glutathione peroxidase 4 (GPX4). Ferroptosis is considered as a potential therapeutic and molecular target for the treatment of necroinflammatory disease, and further investigation into the underlying pathophysiological characteristics and molecular mechanisms implicated may lay the foundations for an interventional therapeutic strategy. This review aims to demonstrate the key roles of ferroptosis in the development of necroinflammatory diseases, the major regulatory mechanisms involved, and its potential as a therapeutic target.

Protective effect of pyrrolidine dithiocarbamate against methotrexate-induced testicular damage

The aim of the study was to investigate the protective effect of pyrrolidine dithiocarbamate (PDTC) against methotrexate (MTX)-induced testicular damage in rats. Forty Wistar albino male rats were divided into equally four groups: Control group (saline solution, IP), PDTC group (100 mg/kg PDTC,IP, 10 days), MTX group (20 mg/kg MTX, IP, single dose, on the 6th day) and MTX + PDTC group (100 mg/kg PDTC, IP, 10 days and 20 mg/kg MTX, IP, single dose, on the 6th day). After 10 days, testicular tissues were excised for morphometric, histological and immunohistochemical evaluations. Serum testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH) and prokineticin 2 (PK2) levels were determined. Body and testicular weights were measured. Testicular damage was assessed by histological evaluation. Nuclear factor kappa B (NFkB), nuclear factor erythroid 2 related factor 2 (Nrf2) and PK2 immunoreactivities were evaluated by HSCORE. Body and testicular weights, serum FSH, LH, testosterone levels, seminiferous tubule diameter and germinal epithelial thickness were significantly decreased in the MTX group. However, serum PK2 level, histologically damaged seminiferous tubules and interstitial field width were significantly increased. Additionally, there was an increase in NFkB and PK2 immunoreactivity, whereas there was a significant decrease in Nrf2 immunoreactivity. PDTC significantly improved hormonal, morphometric, histological and immunohistochemical findings. Taken together, we conclude that PDTC may reduce MTX-induced testicular damage via NFkB, Nrf2 and PK2 signaling pathways.

Topical emulsion containing pyrrolidine dithiocarbamate: effectiveness against ultraviolet B irradiation-induced injury of hairless mouse skin

OBJECTIVES

To evaluate the effects of a topical emulsion containing pyrrolidine dithiocarbamate (PDTC) (EcPDTC) in skin oxidative stress and inflammation triggered by ultraviolet B (UVB) irradiation (dose of 4.14 J/cm² ).

METHODS

Hairless mouse received treatment with 0.5 g of EcPDTC or control emulsion (CTRLE) on the dorsal surface skin 12 h, 6 h and 5 min before and 6 h after the irradiation. Oxidative stress was evaluated by ferric reducing antioxidant power (FRAP), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS) scavenging capacity, reduced glutathione quantitation, catalase activity, superoxide anion production and lipid peroxidation products. Inflammation parameters were as follows: skin oedema, myeloperoxidase activity (neutrophil marker), matrix metalloproteinase-9 activity, collagen fibre damage, mast cell and sunburn cell counts, and cytokine production.

KEY FINDINGS

Topical treatment with EcPDTC protected from UVB-induced skin injury by maintaining the antioxidant capacity levels similar to non-irradiated control group. Furthermore, EcPDTC inhibited UVB irradiation-induced superoxide anion production, lipid peroxidation and reduced skin inflammation by inhibiting skin oedema, neutrophil recruitment, metalloproteinase-9 activity, collagen fibre damage, mast cell and sunburn cell counts, and cytokine (TNF-α and IL-1β) production.

CONCLUSIONS

Topical treatment with EcPDTC improves antioxidant systems and inhibits inflammation, protecting the skin from the damaging effects of UVB irradiation.

Inhibition of nuclear factor-κB signal by pyrrolidine dithiocarbamate alleviates lipopolysaccharide-induced acute lung injury

This study mainly studied the effect of inhibition of nuclear factor-κB (NF-κB) signal by pyrrolidine dithiocarbamate (PDTC) on lipopolysaccharide (LPS)-induced inflammatory response, oxidative stress, and mitochondrial dysfunction in a murine acute lung injury model. The results showed that LPS exposure activated NF-κB and its upstream proteins and caused lung inflammation, oxidative stress, and mitochondrial dysfunction in mice. While inhibition of NF-κB by PDTC adminstration alleviated LPS-induced generation of lymphocytes, IL-1β, and TNF-α. Malondialdehyde, a common oxidative product, was markedly reduced after PDTC treatment in LPS-challenged mice. Furthermore, PDTC alleviated LPS-induced mitochondrial dysfunction via improving ATP synthesis and uncoupling protein 2 expression. In conclusion, inhibition of NF-κB by PDTC alleviated LPS-induced acute lung injury via maintaining inflammatory status, oxidative balance, and mitochondrial function in mice.

Effects of varying degrees of partial bladder outlet obstruction on urinary bladder function of rats: A novel link to inflammation, oxidative stress and hypoxia

OBJECTIVES

The aim of the present study was to investigate the effects of different degrees of obstruction, and the roles of inflammation, oxidative stress, and hypoxia parameters on bladder function.

METHODS

Thirty male Sprague-Dawley rats were divided into 3 groups (n = 10 in each group): (i) sham-operated control; (ii) severe partial bladder outlet obstruction (PBOO); and (iii) moderate PBOO. Severe and moderate PBOO were induced by urethral ligation using 3-Fr and 4-Fr catheters, respectively, for 6 weeks. After 6 weeks, the in vitro contractile responses to carbachol, electrical field stimulation, ATP and KCl were measured in bladder strips. In addition, mRNA and protein expression of nuclear factor kappa B (NF-κB) hypoxia-inducible factor (HIF) and nuclear factor, erythroid 2-like 2 (Nrf2) in bladder were determined by real-time polymerase chain reaction and western blotting. Malondialdehyde (MDA) levels in bladder tissues were also determined.

RESULTS

Rats in the severe PBOO group had the highest bladder weight. Detrusor strips from rats in the severe PBOO group exhibited 61%-82% smaller contractile responses to all four stimuli than those from the sham-operated group. Activity of NF-κB as an inflammatory marker was increased in the severe PBOO group, whereas HIF-1α and HIF-2β protein levels were increased significantly in the moderate PBOO group. A master regulator of oxidative stress, Nrf2 expression was increased in all obstructed rats. MDA levels were higher in the severe PBOO group than in sham-operated group.

CONCLUSION

The results of the present study reveal the importance of oxidative stress-induced NF-κB signaling in bladder dysfunction with severe obstruction. Altered HIF signaling may contribute to the functional impairment after PBOO. Novel and evolving therapies targeting oxidative and/or inflammatory pathways may be a reasonable strategy for the management of lower urinary tract symptoms or benign prostatic hyperplasia.

LUTS in pelvic ischemia: a new concept in voiding dysfunction

Lower urinary tract symptoms (LUTS) are a group of voiding symptoms affecting both genders as they age. Traditionally, LUTS in men were commonly attributed to bladder outlet obstruction (BOO) due to benign prostatic enlargement (BPE). It was later shown that, in approximately one-third to more than one-half of cases, LUTS in men are not associated with BOO. Urodynamic changes in the male bladder and symptom scores in aging men were found to be identical to their age-matched female counterparts. These observations suggested that LUTS in the elderly do not necessarily relate to BOO and may result from local changes in bladder muscle, nerves, and blood vessels. However, aging factors predisposing to bladder dysfunction and LUTS remain unknown. Growing evidence suggests that aging-associated pelvic ischemia may be a primary factor in the development of nonobstructed nonneurogenic overactive bladder and LUTS. First identified in experimental models and later in clinical studies, pelvic ischemia has been shown to compromise the lower urinary tract structure and lead to dysfunction. Structural and functional consequences of bladder and prostate ischemia have been documented in animal models. Clinical studies have shown that bladder and prostate blood flow decreases with aging. The severity of LUTS in elderly patients correlates with the degrees of bladder ischemia. LUTS improvement with α blockers has been associated with increased bladder blood flow. Pelvic ischemia may be an independent factor in nonobstructed nonneurogenic bladder instability and LUTS. Further research into the pathophysiology of LUTS in pelvic ischemia may lead to better management of this problem in the elderly population.

Novel intracellular N-terminal truncated matrix metalloproteinase-2 isoform in skeletal muscle ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) occurs when blood returns to tissues following a period of ischemia. Reintroduction of blood flow results in the production of free radicals and reactive oxygen species that damage cells. Skeletal muscle IRI is commonly seen in orthopedic trauma patients. Experimental studies in other organ systems have elucidated the importance of extracellular and intracellular matrix metalloproteinase-2 (MMP-2) isoforms in regulating tissue damage in the setting of oxidant stress resulting from IRI. Although the extracellular full-length isoform of MMP-2 (FL-MMP-2) has been previously studied in the setting of skeletal muscle IRI, studies investigating the role of the N-terminal truncated isoform (NTT-MMP-2) in this setting are lacking. In this study, we first demonstrated significant increases in FL- and NTT-MMP-2 gene expression in C2C12 myoblast cells responding to re-oxygenation following hypoxia in vitro. We then evaluated the expression of FL- and NTT-MMP-2 in modulating skeletal muscle IRI using a previously validated murine model. NTT-MMP-2, but not FL-MMP-2 expression was significantly increased in skeletal muscle following IRI. Moreover, the expression of toll-like receptors (TLRs) -2 and -4, IL-6, OAS-1A, and CXCL1 was also significantly up-regulated following IRI. Treatment with the potent anti-oxidant pyrrolidine dithiocarbamate (PDTC) significantly suppressed NTT-MMP-2, but not FL-MMP-2 expression and improved muscle viability following IRI. This data suggests that NTT-MMP-2, but not FL-MMP-2, is the major isoform of MMP-2 involved in skeletal muscle IRI.

Pyrrolidine Dithiocarbamate Inhibits NF-KappaB Activation and Upregulates the Expression of Gpx1, Gpx4, Occludin, and ZO-1 in DSS-Induced Colitis

Inflammatory bowel disease (IBD) correlates with oxidative stress, inflammation, and alteration in several signal pathways, including nuclear transcription factor-kappaB (NF-κB). Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, has been widely demonstrated to exhibit an antioxidant and anti-inflammatory function. This study aimed to test the hypothesis that NF-κB inhibitor PDTC confers a beneficial role in a colitis model induced by dextran sodium sulfate (DSS) in mouse. The results showed that DSS decreased daily weight gain, induced colonic inflammation, suppressed the expression of antioxidant enzymes and tight junctions, and activated NF-κB and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathways. PDTC significantly upregulated (P < 0.05) Gpx1, Gpx4, occludin, and ZO-1 expressions in the DSS-induced colitis model. Meanwhile, PDTC reversed (P < 0.05) the activation of NF-κB signal pathway caused by DSS treatment. In conclusion, PDTC could serve as an adjuvant therapy for the patient with IBD.

Emodin has a protective effect in cases of severe acute pancreatitis via inhibition of nuclear factor‑κB activation resulting in antioxidation

Severe acute pancreatitis (SAP) accounts for up to 20% of acute pancreatitis (AP) cases. The absence of effective treatment options has resulted in a high rate of morbidity and mortality. Emodin is a major component of the Chinese herb rhubarb, which has been widely used in the treatment of numerous diseases, including inflammation and cancer. There are a limited number of studies however, that have investigated the effectiveness of emodin in the treatment of SAP. The present study used a rat model of SAP, to investigate the effect and molecular mechanisms of emodin treatment. Administration of emodin was identified to significantly attenuate SAP, as determined by serum amylase analysis and histological assessment of edema, vacuolization, inflammation and necrosis (P<0.01). Furthermore, treatment with emodin markedly inhibited nuclear factor (NF)‑κB DNA‑binding activity (P<0.01) and the serum expression levels of tumor necrosis factor‑α, interleukin (IL)‑6 and IL‑1β (P<0.05). This attenuation was associated with decreased malondialdehyde and increased superoxide dismutase levels in the pancreatic tissues and serum (P<0.05). This study indicated that administration of exogenous emodin had therapeutic effects on the severity of SAP. The mechanism may be due to inhibition of NF‑κB activation resulting in an antioxidation response, which can subsequently suppress the expression of cytokines.

Pyrrolidine dithiocarbamate inhibits enterovirus 71 replication by down-regulating ubiquitin-proteasome system

Enterovirus 71 (EV71) is the main causative pathogen of hand, foot, and mouth disease (HFMD). The severe neurological complications caused by EV71 infection and the lack of effective therapeutic medicine underline the importance of searching for antiviral substances. Pyrrolidine dithiocarbamate (PDTC), an antioxidant, has been reported to inhibit the replication of coxsackievirus B (CVB) through dysregulating ubiquitin-proteasome system (UPS). In this study, we demonstrated that PDTC exerted potent antiviral effect on EV71. Viral RNA synthesis, viral protein expression, and the production of viral progeny were significantly reduced by the treatment of PDTC in Vero cells infected with EV71. Similar to the previous report about the inhibitory effect of PDTC on UPS, we found that PDTC treatment led to decreased levels of polyubiquitinated proteins in EV71-infected cells. The inhibitory effect of PDTC on UPS was further confirmed by the increased accumulation of cell cycle regulatory proteins p21 and p53, which are normally degraded through UPS, while the expression levels of both proteins remained unchanged. We also showed that PDTC had no impact on the activity of proteasome. Thus, we demonstrated that the down-regulation of PDTC on UPS was the result of its inhibition on ubiquitination. More importantly, this study provides evidence that the inhibition on UPS was required for the antiviral activity of PDTC, since MG132, a potent proteasome inhibitor, significantly inhibited the cytopathic effect and viral protein synthesis in EV71-infected cells. We also found that the antioxidant property of PDTC did not contribute to its antiviral effect, since N-acetyl-l-cysteine, a potent antioxidant, could not inhibit viral replication. In addition, CPE and viral protein synthesis were not inhibited in the cells pretreated with PDTC 2h before viral infection and then cultured in the media with no PDTC supplement, while the antioxidant effect of PDTC was retained. PDTC also showed significant inhibition on apoptosis induced by EV71 infection when it was applied at the early stage of viral infection. Our results collectively suggest that PDTC could be a potential anti-EV71 compound which possesses both antiviral and anti-apoptotic capacity.