Hypercytokinemia is a critically fatal factor in COVID-19. However, underlying pathogenic mechanisms are unknown. Here we show that brinogen and leukotriene-A4 hydrolase (LTA4H), two of the most potent in ammatory contributors, are elevated by 67.7 and astonishing 227.7% in the plasma of patients infected by SARS-CoV-2 and admitted to intensive care unit in comparison with healthy control, respectively. Conversely, transferrin identi ed as a brinogen immobilizer in our recent work and Spink6 are down-regulated by 40.3 and 25.9%, respectively. Furthermore, we identify Spink6 as the rst endogenous inhibitor of LTA4H, a pro-in ammatory enzyme catalyzing nal and rating limited step in biosynthesis of leukotriene-B4 that is an extremely in ammatory mediator and a target to design superior anti-in ammatory drugs. Additionally, virus Spike protein is found to evoke LTA4H and brinogen expression in vivo. Collectively, these ndings identify the imbalance between in ammatory drivers and antagonists, which likely contributes to hypercytokinemia in COVID-19. Spink6 may have superior antiin ammatory function because it speci cally targets epoxide hydrolase of LTA4H to inhibit leukotriene-B4 biosynthesis without effecting LTA4H's aminopeptidase activity.

Alzheimer's disease (AD) is an age-related devastating neurodegenerative disorder, which severely impacts on the global economic development and healthcare system. Though AD has been studied for more than 100 years since 1906, the exact cause(s) and pathogenic mechanism(s) remain to be clarified. Also, the efficient disease-modifying treatment and ideal diagnostic method for AD are unavailable. Perturbed cerebral glucose metabolism, an invariant pathophysiological feature of AD, may be a critical contributor to the pathogenesis of this disease. In this review, we firstly discussed the features of cerebral glucose metabolism in physiological and pathological conditions. Then, we further reviewed the contribution of glucose transportation abnormality and intracellular glucose catabolism dysfunction in AD pathophysiology, and proposed a hypothesis that multiple pathogenic cascades induced by impaired cerebral glucose metabolism could result in neuronal degeneration and consequently cognitive deficits in AD patients. Among these pathogenic processes, altered functional status of thiamine metabolism and brain insulin resistance are highly emphasized and characterized as major pathogenic mechanisms. Finally, considering the fact that AD patients exhibit cerebral glucose hypometabolism possibly due to impairments of insulin signaling and altered thiamine metabolism, we also discuss some potential possibilities to uncover diagnostic biomarkers for AD from abnormal glucose metabolism and to develop drugs targeting at repairing insulin signaling impairment and correcting thiamine metabolism abnormality. We conclude that glucose metabolism abnormality plays a critical role in AD pathophysiological alterations through the induction of multiple pathogenic factors such as oxidative stress, mitochondrial dysfunction, and so forth. To clarify the causes, pathogeneses and consequences of cerebral hypometabolism in AD will help break the bottleneck of current AD study in finding ideal diagnostic biomarker and disease-modifying therapy.

Oxidative stress plays a significant role in the pathogenesis of Alzheimer's disease (AD), a devastating disease of the elderly. The brain is more vulnerable than other organs to oxidative stress, and most of the components of neurons (lipids, proteins, and nucleic acids) can be oxidized in AD due to mitochondrial dysfunction, increased metal levels, infl ammation, and β-amyloid (Aβ) peptides. Oxidative stress participates in the development of AD by promoting Aβ deposition, tau hyperphosphorylation, and the subsequent loss of synapses and neurons. The relationship between oxidative stress and AD suggests that oxidative stress is an essential part of the pathological process, and antioxidants may be useful for AD treatment.Keywords: Alzheimer's disease; oxidative stress; β-amyloid; tau; metals; antioxidants ·Review· IntroductionThe human brain, although it constitutes only 2% of the body weight, consumes ~20% of the oxygen supplied by the respiratory system [1] . The high energy-consumption of the brain means that it is more susceptible to oxidative stress than any other organ. As the basic functional unit of the brain, the neuron is particularly vulnerable to oxidative damage because it has a higher metabolic rate than other cells [2] . The oxidation of lipids, proteins, and nucleic acids in neurons is a common pathological feature of Alzheimer's disease (AD) [3] . Neurons contain a large amount of polyunsaturated fatty acids (PUFAs) that can interact with reactive oxygen species (ROS), leading to a selfpropagating cascade of lipid peroxidation and molecular destruction [4] . Furthermore, neurons contain low levels of glutathione, an essential antioxidant for eliminating free radicals [5] . Therefore, neurons are highly susceptible to oxidative stress.An increased oxidative burden has been reported in the brains of non-demented elderly and/or sporadic AD patients [6,7] . Increased levels of oxidative stress biomarkers in the blood reflect such stress in the brain [8,9] . Currently, many blood markers of oxidative stress have been identified in AD patients or related animal models, including protein carbonyls and 3-nitrotyrosine [10,11] , , malondialdehyde (MDA) [12] , 4-hydroxynonenal (4-HNE), and F2-isoprostanes (F2-IsoPs) [13][14][15][16] . Apart from the intracellular accumulation of free radicals, changes in the activities or expressions of antioxidant enzymes, such as superoxide dismutase (SOD) and catalase, have also been described in both the central nervous system and peripheral tissues of AD patients [14,17] . Thus, oxidative stress is an important pathological feature in AD.However, how and where the oxidative stress originates in AD are open questions. Research has suggested that mitochondrial dysfunction [12,18,19] , metal accumulation [12,20,21] , hyperphosphorylated tau [22,23] , inflammation [24,25] , and β-amyloid (Aβ) accumulation [12,19] are the basic mechanisms underlying the induction of oxidative stress. Deficiency or destruction of components of the antioxidant system such as SOD in the mi...

Growing evidence has indicated that iron deposition in the substantia nigra plays an important role in Parkinson’s disease (PD). However, the underlying mechanism is still elusive. Using primary dopaminergic neurons and SH-SY5Y cells cultured in vitro, we observed that iron loading increased α-synuclein and reactive oxygen species (ROS) levels in these cells but did not affect the intracellular α-synuclein mRNA levels. Furthermore, iron loading significantly downregulated Beclin-1 levels and decreased the ratio of microtubule-associated protein 1 light chain 3 isoforms (LC3 II/LC3 I). However, a significant change in the levels of autophagy-related gene 5 (Atg5) was not observed in either neurons or SH-SY5Y cells after iron treatment. After treatment with rapamycin, the iron loading-induced increase in the α-synuclein level was significantly reversed and ROS generation was alleviated in both cultured neurons and SH-SY5Y cells. These results indicate that the inhibition of autophagy is critical for the pathological alterations in α-synuclein induced by iron loading. Moreover, treatment with vitamin E did not affect the increase in the α-synuclein levels but significantly eliminated the iron-induced ROS production. Together, our study shows that autophagy dysfunction contributes to iron-induced α-synuclein pathology.

Reduction of glucose metabolism in brain is one of the main features of Alzheimer's disease. Thiamine (vitamin B1)-dependent processes are critical in glucose metabolism and have been found to be impaired in brains from patients with Alzheimer's disease. However, thiamine treatment exerts little beneficial effect in these patients. Here, we tested the effect of benfotiamine, a thiamine derivative with better bioavailability than thiamine, on cognitive impairment and pathology alterations in a mouse model of Alzheimer's disease, the amyloid precursor protein/presenilin-1 transgenic mouse. We show that after a chronic 8 week treatment, benfotiamine dose-dependently enhanced the spatial memory of amyloid precursor protein/presenilin-1 mice in the Morris water maze test. Furthermore, benfotiamine effectively reduced both amyloid plaque numbers and phosphorylated tau levels in cortical areas of the transgenic mice brains. Unexpectedly, these effects were not mimicked by another lipophilic thiamine derivative, fursultiamine, although both benfotiamine and fursultiamine were effective in increasing the levels of free thiamine in the brain. Most notably, benfotiamine, but not fursultiamine, significantly elevated the phosphorylation level of glycogen synthase kinase-3alpha and -3beta, and reduced their enzymatic activities in the amyloid precursor protein/presenilin-1 transgenic brain. Therefore, in the animal Alzheimer's disease model, benfotiamine appears to improve the cognitive function and reduce amyloid deposition via thiamine-independent mechanisms, which are likely to include the suppression of glycogen synthase kinase-3 activities. These results suggest that, unlike many other thiamine-related drugs, benfotiamine may be beneficial for clinical Alzheimer's disease treatment.

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Purpose: Head and neck squamous cell carcinomas have been reported to overexpress hypoxia-inducible factor (HIF)-1␣, a transcription factor that promotes expression of angiogenesis factors and resistance to programmed and therapy-induced cell death. 2-Methoxyestradiol (2ME2) is a natural compound with HIF-1␣ inhibitory activity that is currently being evaluated in phase 1 and 2 clinical trials for advanced solid tumors and multiple myeloma. To our knowledge, this is the first study to evaluate the effects of 2ME2 in head and neck squamous cell carcinoma.Experimental Design: In the present study, we investigated the effects of 2ME2 alone and in combination with paclitaxel, an active agent in recurrent or advanced head and neck squamous cell carcinoma.Results: 2ME2 exhibited antiproliferative and cytotoxic effects in a panel of five head and neck squamous cell carcinoma cell lines in the 0.5 to 10 mol/L range, including induction of G 2 -M blockade, caspase-3/7 activation, and apoptosis at 48 hours. 2ME2 resulted in decreased nuclear HIF-1␣-binding activity and affected the expression of downstream genes, such as bid, a proapoptotic bcl-2 family member, and vascular endothelial growth factor, a proangiogenic cytokine. The up-regulation of Bid (57.5% at 12 hours, P < 0.0006) and inhibition of vascular endothelial growth factor secretion (57.7% at 24 hours, P < 0.015; and 50.3% at 48 hours, P < 0.0006) could be partially attributed to the effects on HIF-1␣, because HIF-1␣ small interfering RNAs produced similar effects. Finally, in vivo, in a xenograft model of head and neck squamous cell carcinoma using UM-SCC-11A cells, 2ME2 exhibited antitumor and antiangiogenic activity, as measured by CD31 immunostaining.Conclusions: These results provide support for the use of 2ME2 in combination with paclitaxel for the treatment of recurrent or advanced head and neck squamous cell carcinoma.

In vivo and post-mortem studies have demonstrated that increased nigral iron content in patients with Parkinson's disease is a prominent pathophysiological feature. However, the mechanism and risk factors associated with nigral iron deposition in patients with Parkinson's disease have not been identified and represent a key challenge in understanding its pathogenesis and for its diagnosis. In this study, we assessed iron levels in patients with Parkinson's disease and in age- and gender-matched control subjects by measuring phase values using magnetic resonance based susceptibility-weighted phase imaging in a 3T magnetic resonance system. Phase values were measured from brain regions including bilateral substantia nigra, globus pallidus, putamen, caudate, thalamus, red nucleus and frontal white matter of 45 patients with Parkinson's disease with decreased or normal serum ceruloplasmin levels, together with age- and gender-matched control subjects. Correlative analyses between phase values, serum ceruloplasmin levels and disease severity showed that the nigral bilateral average phase values in patients with Parkinson's disease were significantly lower than in control subjects and correlated with disease severity according to the Hoehn and Yahr Scale. The Unified Parkinson's Disease Rating Scale motor scores from the clinically most affected side were significantly correlated with the phase values of the contralateral substantia nigra. Furthermore, nigral bilateral average phase values correlated highly with the level of serum ceruloplasmin. Specifically, in the subset of patients with Parkinson's disease exhibiting reduced levels of serum ceruloplasmin, we found lowered nigral bilateral average phase values, suggesting increased nigral iron content, while those patients with normal levels of serum ceruloplasmin exhibited no changes as compared with control subjects. These findings suggest that decreased levels of serum ceruloplasmin may specifically exacerbate nigral iron deposition in patients with Parkinson's disease. Combining susceptibility-weighted phase imaging with serum ceruloplasmin determination is likely to be useful for the diagnosis and assessment of a subset of patients with Parkinson's disease.