Ferritinophagy-mediated ferroptosis facilitates methotrexate-induced hepatotoxicity by high-mobility group box 1 (HMGB1)

BACKGROUND AND AIM

Hepatotoxicity is a well-defined reaction to methotrexate (MTX), a drug commonly used for the treatment of rheumatoid arthritis and various tumours. We sought to elucidate the mechanism underlying MTX-induced hepatotoxicity and establish a potentially effective intervention strategy.

METHODS

We administered MTX to liver cells and mice and assessed hepatotoxicity by cell viability assay and hepatic pathological changes. We determined ferroptosis and ferritinophagy by detecting ferroptosis-related markers and autophagic degradation of ferritin heavy chain 1 (FTH1).

RESULTS

We have shown that hepatocytes treated with MTX undergo ferroptosis, and this process can be attenuated by ferroptosis inhibitors. Interestingly, NCOA4-mediated ferritinophagy was found to be involved in MTX-induced ferroptosis, which was demonstrated by the relief of ferroptosis through the inhibition of autophagy or knockdown of Ncoa4. Furthermore, MTX treatment resulted in the elevation of high-mobility group box 1 (HMGB1) expression. The depletion of Hmgb1 in hepatocytes considerably alleviated MTX-induced hepatotoxicity by limiting autophagy and the subsequent autophagy-dependent ferroptosis. It is noteworthy that glycyrrhizic acid (GA), a precise inhibitor of HMGB1, effectively suppressed autophagy, ferroptosis and hepatotoxicity caused by MTX.

CONCLUSION

Our study shows the significant roles of autophagy-dependent ferroptosis and HMGB1 in MTX-induced hepatotoxicity. It emphasizes that the inhibition of ferritinophagy and HMGB1 may have potential as a therapeutic approach for preventing and treating MTX-induced liver injury.

Long-term neurodevelopment outcomes of hand, foot and mouth disease inpatients infected with EV-A71 or CV-A16, a retrospective cohort study

Hand, foot and mouth disease (HFMD) is a common infectious disease in western Asia area and the full range of the long-term sequelae of HFMD remains poorly described. We conducted a retrospective hospital-based cohort study of HFMD patients with central nervous system (CNS) complications caused by EV-A71 or CV-A16 between 2010 and 2016. Patients were classified into three groups, including CNS only, autonomic nervous system (ANS) dysregulation, and cardiorespiratory failure. Neurologic examination, neurodevelopmental assessments, Magnetic Resonance Imaging (MRI) and lung function, were performed at follow up. Of the 176 patients followed up, 24 suffered CNS only, 133 ANS dysregulation, and 19 cardiorespiratory failure. Median follow-up period was 4.3 years (range [1.4-8.3]). The rate of neurological abnormalities was 25% (43 of 171) at discharge and 10% (17 of 171) at follow-up. The rates of poor outcome were significantly different between the three groups of complications in motor (28%, 38%, 71%) domain (p=0.020), but not for cognitive (20%, 24%, 35%), language (25%, 36%, 41%) and adaptive (24%, 16%, 26%) domains (p = 0.537, p = 0.551, p = 0.403). For children with ventilated during hospitalization, 41% patients (14 of 34) had an obstructive ventilatory defect, and one patient with scoliosis had mixed ventilatory dysfunction. Persistent abnormalities on brain MRI were 0% (0 of 7), 9% (2 of 23) and 57% (4 of 7) in CNS, ANS and cardiorespiratory failure group separately. Patients with HFMD may have abnormalities in neurological, motor, language, cognition, adaptive behaviour and respiratory function. Long-term follow-up programmes for children's neurodevelopmental and respiratory function may be warranted.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

[Expressions of P-JNK in nerve cell apoptosis of A2AR knockout newborn mice after hypoxia/ischemia brain damage]

OBJECTIVE

To investigate the effect of adenosine A2A receptor knockout (A(2A)RKO) on relationship between continuous activation of phospho-c-Jun N-terminal kinase (P-JNK) and expression of nerve cell apoptosis in hippocampus CA1 domain of newborn mice after hypoxia/ischemia brain damage(HIBD) and its potential mechanism.

METHODS

A(2A)RKO mice and adenosine A2A receptor wildtype (A(2A)RWT) littermates (n = 80) were divided into Sham operation group (S) and model group (M), 1, 3 and 7 day after HIBD, totally 8 groups. HIBD was developed with 7 day-old neonatal mice according classical Rice-Vannucci method. It was tested the effect of A(2A)RKO on short-term neurofunctional outcomes consisted of three developmental reflexes (righting, geotaxis and cliff aversion), the changes of brain pathology with hematoxylin-eosin (HE) staining and Nissl staining, the expressions of nerve cell apoptosis with terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling(TUNEL) staining and P-JNK were observed by immunohistochemistry.

RESULTS

The neurological behavior injuries and brain histopathological damages and nerve apoptosis cells were aggravated in A(2A)RKO newborn mice after HIBD. The positive expressions of P-JNK were significantly higher in the ischemic hippocampus CA1 domain after HIBD than ones in group S respectively (P < 0.01), reaching to peak at 1 day and then began gradually decreasing. P-JNK expression in model knockout(MKO) at 1, 3 and 7 day increased greatly compared to those in the previous time point of corresponding model wildtype (MWT) (P < 0.01, P < 0.05, P > 0.05); there was a positive correlation between the expressions of P-JNK and nerve cell apoptosis after HIBD in newborn mice(r = 0.837, P < 0.01).

CONCLUSION

Early continuous activation of P-JNK might be involved in the aggravated nerve apoptosis cells and brain damage induced by A(2A) RKO newborn mice after HIBD.

Genetic architecture of the circadian clock and flowering time in Brassica rapa

The circadian clock serves to coordinate physiology and behavior with the diurnal cycles derived from the daily rotation of the earth. In plants, circadian rhythms contribute to growth and yield and, hence, to both agricultural productivity and evolutionary fitness. Arabidopsis thaliana has served as a tractable model species in which to dissect clock mechanism and function, but it now becomes important to define the extent to which the Arabidopsis model can be extrapolated to other species, including crops. Accordingly, we have extended our studies to the close Arabidopsis relative and crop species, Brassica rapa. We have investigated natural variation in circadian function and flowering time among multiple B. rapa collections. There is wide variation in clock function, based on a robust rhythm in cotyledon movement, within a collection of B. rapa accessions, wild populations and recombinant inbred lines (RILs) derived from a cross between parents from two distinct subspecies, a rapid cycling Chinese cabbage (ssp. pekinensis) and a Yellow Sarson oilseed (ssp. trilocularis). We further analyzed the RILs to identify the quantitative trait loci (QTL) responsible for this natural variation in clock period and temperature compensation, as well as for flowering time under different temperature and day length settings. Most clock and flowering-time QTL mapped to overlapping chromosomal loci. We have exploited micro-synteny between the Arabidopsis and B. rapa genomes to identify candidate genes for these QTL.

Plasma EBV DNA and cell-free GAPDH DNA as prognostic factors of locally advanced nasopharyngeal carcinoma

6053

Background: Plasma cell-free nucleic acids have been investigated to be potential prognostic and predictive markers of treatment response, residual disease, and survival of cancer patients. However, these nucleic acids will be confounded by normal cell death, which might be caused by cancer-related inflammation, infection, or chemotherapy. Nasopharyngeal carcinoma is endemic in Taiwan, highly related to EBV infection. Plasma EBV DNA level has been suggested to be predictive of disease status and outcomes. We try to find out whether plasma EBV and cell-free glyceraldehydes-3-phosphate dehydrogenase DNA before definite treatment of locally advanced NPC predict tumor outcomes better. Methods: 144 stage IV (AJCC version 6) NPC patients received induction chemotherapy followed by concurrent chemoradiotherapy in National Taiwan University Hospital from 1998 to 1999. Pre-treatment blood samples were colleted for real-time quantitative polymerase chain reactions of EBV and GAPDH DNA. The results will be analyzed by SPSS version 13 to see if correlated with tumor extent, locoregional/distant failure, and overall survival. Results: Our patients were mainly composed of T4(97%) and N2(56%) patients. 23 % were in N3 stage. Plasma EBV and cell-free GAPDH DNA levels were not correlated with T stage. Plasma EBV DNA level was significantly correlated with N3 status(Mann-Whitney test p=0.021). After Cox regression model, only age (p=0.024) was a significant predictor of recurrence-free survival; N3 status(p=0.007) and positive plasma EBV DNA (p=0.002) predicted shorter metastasis-free survival. N3 status (p=0.031) and positive plasma EBV DNA (p=0.002) were significantly related to poor survival by log-rank test; whereas T4 lesions (p=0.524) and plasma cell-free GAPDH DNA level (p=0.182) were not. After multivariate Cox regression, positive plasma EBV DNA (hazard ratio 4.936 p=0.006) was the only significant predictor of poor survival. Conclusions: To use circulating DNA as prognostic marker, a specific one, such as EBV DNA, might be better than a non-specific one, like GAPDH DNA. This is important in the development of tumor markers for other solid tumors.

No significant financial relationships to disclose.

Selective inhibition of endothelial cell proliferation by fumagillin is not due to differential expression of methionine aminopeptidases

The angiogenesis inhibitors fumagillin and TNP-470 selectively inhibit the proliferation of endothelial cells, as compared with most other cell types. The mechanism of this selective inhibition remains uncertain, although methionine aminopeptidase-2 (MetAP2) has recently been found to be a target for fumagillin or TNP-470, which inactivates MetAP2 enzyme activity through covalent modification. Primary cultures of human endothelial cells and six other non-endothelial cell types were treated with fumagillin to determine its effect on cell proliferation. Only the growth of endothelial cells was completely inhibited at low concentrations of fumagillin. MetAP1 and MetAP2 levels in these cells were investigated to determine whether differential enzyme expression plays a role in the selective action of fumagillin. Western blot analysis and RT-PCR data showed that MetAP1 and MetAP2 were both expressed in these different types of cells, thus, ruling out differential expression of MetAP1 and MetAP2 as an explanation for the cell specificity of fumagillin. Expression of MetAP2, but not of MetAP1, is regulated. Treatment of human microvascular endothelial cells (HMVEC) with fumagillin resulted in threefold increases of MetAP2 protein in the cells, while MetAP1 remained constant. Similar upregulation of MetAP2 by exposure to fumagillin was also observed in non-endothelial cells, eliminating this response as an explanation for cell specificity. Taken together, these results indicate that while MetAP2 plays a critical role in the effect of fumagillin on endothelial cell proliferation, differential endogenous expression or fumagillin-induced upregulation of methionine aminopeptidases is not responsible for this observed selective inhibition.

Expression of E-cadherin/catenin complex in nasopharyngeal carcinoma: correlation with clinicopathological parameters

The E-cadherin/catenin complex plays an essential role in maintaining intimate intercellular associations and is considered to be involved in tumor metastasis and suppressing invasion by cancer cells. We have analyzed the expression of E-cadherin/catenin complex in a series of nasopharyngeal carcinoma (NPC) specimens using immunohistochemistry and immunoblotting. Data are correlated with the patients' clinicopathological parameters, including the clinical stage, presence of intracranial invasion, presence of lymph node or distant metastasis, and histological grading. The E-cadherin/catenin complex is down-expressed in most of the samples examined. Correlation with clinicopathological parameters shows that expression of alpha- and beta-catenin is associated with the occurrence of intracranial invasion.

Monocyte chemoattractant protein-1 expression in aortic tissues of hypertensive rats

Monocyte chemoattractant protein-1 (MCP-1), a potent monocyte chemoattractant synthesized by vascular cells and monocytes, has been proposed to be an important mediator of inflammatory responses in the arterial vasculature. It was recently demonstrated that hypertension is associated with an inflammatory response in the arterial wall. To determine the effect of hypertension on arterial MCP-1 expression, we induced hypertension in Sprague-Dawley rats by infusing angiotensin II (0.75 mg x kg[-1] x d[-1] SC) for 7 days. Using Northern blot analysis, we detected a 3.6-fold increase in MCP-1 mRNA in the aortas of hypertensive rats. When we normalized blood pressure in angiotensin II-treated rats through oral administration of the nonspecific vasodilator hydralazine (15 mg x kg[-1] x d[-1]), aortic MCP-1 mRNA expression was significantly reduced. Similar results were obtained with a norepinephrine model of hypertension. Taken together, these data suggest that mechanical factors may be responsible in part for the upregulation of expression. Consistent with this interpretation, we found that cultured rat aortic vascular smooth muscle cells exposed to mechanical strain (20% peak deformation at 1 Hz) exhibited a marked increase in MCP-1 expression, suggesting the hemodynamic strain imparted onto arterial cells in hypertension is an important stimulus underlying this phenomenon. These results provide important insights into the in vivo regulation of MCP-1 and have potential implications for understanding the influence of hypertension on atherosclerosis.

Vascular thrombin receptor regulation in hypertensive rats

Thrombin has been implicated as an important mediator of vascular lesion formation in atherosclerosis and restenosis. To investigate a potential role for thrombin signaling in the vascular response to hypertension, we have studied thrombin receptor (TR) expression and regulation in hypertensive rats. Aortic TR mRNA was upregulated by angiotensin II (Ang II)-induced hypertension (10.7 +/- 2.5 times control, P < .02), which correlated with a 4-fold increase in thrombin-induced constriction in isolated endothelium-denuded aortic rings. The AT1 receptor antagonist losartan normalized blood pressure and TR mRNA. Conversely, lowering blood pressure to the same degree with hydralazine did not abolish the upregulation of TR mRNA expression. When low-renin low-Ang II hypertension was induced in Dahl salt-sensitive rats, there was no detectable increase in the expression of aortic thrombin receptor mRNA. Finally, treatment with a chimeric heparin-binding form of the recombinant human Cu/Zn superoxide dismutase caused complete inhibition of TR mRNA upregulation, suggesting that an increased rate of superoxide anion production is an important signaling mechanism. Thus, increased TR expression via a redox-sensitive mechanism in the aortic smooth muscle of rats treated with Ang II represents a novel in vivo mechanism through which the hypertensive effects of Ang II are mediated.

Iron-ascorbate-phospholipid mediated modification of low density lipoprotein

LDL can be oxidized by a variety of agents to form a modified lipoprotein which is capable of being avidly metabolized by macrophages. While previous in vitro studies have focused exclusively on the oxidation of LDL, other lipids found in the atheroma are also subject to oxidation and its lipoperoxide byproducts may contribute to the process of LDL modification. To examine the relationship between the oxidation of phospholipids and the subsequent modification of LDL, we incubated 250 microM phosphatidylcholine with 10 microM ferrous sulfate and 50 microM ascorbic acid in 10 mM Tris (pH 7.0). After 18 h at 37 degrees C, significant amounts of thiobarbituric acid reactive substances (TBARS) were formed. The inclusion of LDL (100 micrograms protein/ml) elevated the TBARS and increased the electrophoretic mobility of the lipoprotein. LDL treated with iron and ascorbate in the absence of phosphatidylcholine did not result in the modification of this lipoprotein. LDL that was incubated with phosphatidylcholine, iron and ascorbate was found to be metabolized by macrophages to a far greater extent than native LDL or LDL treated with phosphatidylcholine alone. Probucol (10 microM) inhibited the LDL modification process. These results demonstrate that while iron and ascorbate cannot oxidize LDL directly, the addition of phosphatidylcholine to these initiators of lipid peroxidation can mediate and lead to the modification of LDL.

Cholesteryl ester accumulation in macrophages treated with oxidized low density lipoprotein

The ability of CuSO4- and hypochlorite-oxidized LDL to promote cholesterol accumulation in macrophages was examined. Both CuSO4- and hypochlorite-oxidized LDL were rapidly metabolized by mouse peritoneal macrophages to a level approximately 10 times that observed for native LDL and both modified lipoproteins increased the accumulation of unesterified cholesterol. However when each modified lipoprotein was incubated with macrophages for 40h, only hypochlorite-oxidized LDL produced significant accumulation of cholesteryl esters, with levels approaching 85 micrograms/mg cell protein. This finding was verified by nile red staining. The cholesteryl ester content of cupric sulfate-modified LDL was found to be significantly decreased when compared to either native or hypochlorite-modified LDL promotes massive cholesteryl ester accumulation because the cholesteryl ester content of the LDL particle is preserved.

Effects of phosphatidylserine on the oxidation of low density lipoprotein

1. LDL was incubated in the presence of 1 microM CuSO4 for 18 hr at 37 degrees C. The content of lipoperoxides was found to be approx. 40 nmol MDA equivalents/mg LDL protein. The addition of 50 microM phosphatidylserine (PS) reduced the content of lipoperoxides to 15% of control values. 2. The electrophoretic mobility observed for LDL oxidized in the presence of PS approximated the mobility observed for native LDL. 3. The formation of conjugated dienes was strongly inhibited when LDL was oxidized in the presence of PS. 4. The addition of 50 microM phosphatidylcholine, phosphatidylglycerol and cardiolipin did not alter the extent of LDL oxidation. 5. PS did not inhibit the oxidation of LDL mediated by J774 macrophages in the presence of Ham's F-10 culture medium. Under these conditions, PS was found to be an excellent substrate for oxidation.

Spectrofluorometric studies of nile red treated native and oxidized low density lipoprotein

1. The excitation and emission maxima of nile red in the presence of LDL were found to be 526 and 587 nm, respectively. Oxidation of LDL for 16 hr in the presence of CuSO4 resulted in significant spectral shifts to longer wavelengths in both the excitation and emission spectra. 2. The difference in the fluorescence intensity between native and oxidized LDL was most pronounced at wavelengths between 550 and 580 nm. At these emission wavelengths, the relative fluorescence intensity of nile red treated oxidized LDL was found to be decreased by approx 30% when compared to that observed in the presence of native LDL. 3. Differences in the nile red fluorescence spectra were not observed when LDL and acetylated LDL were compared.

Dystrophic calcification of silicone scleral buckling implant materials

In six patients, removal of solid silicone scleral buckling implant materials that had been in place between eight and 21 years disclosed gray-white deposits firmly adherent to the silicone. Four of the six patients had culture-proven infections, whereas two had no evidence of infection and had negative cultures. One of these two patients, however, had intermittent pain, which was the indication for removal of the implant. Analysis of the deposits disclosed that they were calcium phosphate. The exact mechanism responsible for the calcification on the silicone material is unknown. Dystrophic calcification can occur without infection in injured tissue wherein extracellular deposits of devitalized cells, blood cells, and lipids may act as a nidus for calcification. In the presence of infection, bacteria may serve as such a nidus. Additionally, it is possible that biofilm produced by the bacteria had a role in the deposition of calcium phosphate, as well as in its firm adhesion to the silicone materials. We considered the possibility of similar deposits developing on intraocular silicone lenses.

Dothiepin hydrochloride: treatment efficacy and safety

Dothiepin, a thio analogue of amitriptyline, has been used extensively in Europe during the past 15 years. It is a safe and effective agent for the treatment of major depressive disorder. Although the onset of action is comparable to that of other tricyclic antidepressants, dothiepin may cause fewer intolerable side effects and have less cardiotoxicity than these other compounds. In addition, dothiepin reduces the anxiety associated with some major depressive episodes. These features suggest that dothiepin may be particularly helpful for treating anxious depressed patients and patients who have underlying cardiac disease or who are elderly.

Intensive conventional and insulin pump therapies in adult type I diabetes. A crossover study

We examined the relative efficacy of two modes of insulin therapy in five patients with insulin-dependent diabetes. Using a crossover protocol, therapy with multiple insulin injections was compared with the use of continuous subcutaneous insulin infusion (pump therapy); both therapies were regulated by home blood glucose monitoring. Although both therapies were equally effective during 2 to 4 days of inpatient management, pump therapy was clearly superior in the outpatient setting. Mean plasma glucose and hemoglobin A1c concentrations and the frequency of hypoglycemic reactions were significantly less with pump therapy despite apparently equal compliance with both therapies. We conclude that in compliant adult patients with type I diabetes continuous insulin infusion is more effective in achieving normalization of plasma glucose concentration than intensified conventional therapy in the outpatient setting. Although these patients found pump therapy preferable to intensive conventional therapy, the superiority of pump therapy is not explained by this bias. Whether these results are applicable in a more standard treatment setting remains to be established.

Ocular toxoplasmosis in three consecutive siblings

Ocular toxoplasmosis in consecutive siblings is rare. We report positive ocular and serologic findings in three consecutive teenaged siblings. Results of immunologic studies that were performed on members of the family failed to reveal deficiencies.

Biosynthesis of proteins by the retina. Inactivation by near-ultraviolet light and the effects of tryptophan, epinephrine, and catalase

Postmitochondrial supernatant, cytosol, and microsomes were exposed to near-ultraviolet light and assayed for incorporation of (3H)leucine. The results indicate that near-ultraviolet light decreased the incorporation of radioactivity into the aminoacyl-tRNA fraction and into proteins. This effect depended on the wavelength of irradiation and the concentration of exposed protein. Tryptophan and epinephrine potentiated the effect of near-ultraviolet light, but catalase prevented this effect. Hydrogen peroxide decreased protein synthesis when it was added to unirradiated postmitochondrial supernatant. The results suggest that near-ultraviolet light would decrease protein synthesis by generating hydrogen peroxide from tryptophan and epinephrine.

Computed tomography of choroidal melanoma and scleral buckle

In the investigation of a patient with choroidal melanoma in one eye and repaired rhegmatogenous retinal detachment in the other, a C.T. scan demonstrated the tumour in the right globe and the encircling silastic sponge around the left globe. These radiologic findings were confirmed on histological examination of the right eye. We believe C.T. scanning may be a valuable technique for investigating bulbar and para-bulbar soft tissue abnormalities.

Successful treatment of Candida endophthalmitis with a synergistic combination of amphotericin B and rifampin

Candida endophthalmitis, caused by transient candidemia, developed in a 14-year-old white girl receiving intravenous hyperalimentation. Antifungal synergism was established in vitro for the combination of amphotericin B and rifampin against the C. albicans isolate. A combined ten-day course of intravenous amphotericin B and oral rifampin was followed by the elimination of the infection and the preservation of good visual acuity.