Chaiqin chengqi decoction alleviates severity of acute pancreatitis via inhibition of TLR4 and NLRP3 inflammasome: Identification of bioactive ingredients via pharmacological sub-network analysis and experimental validation

BackgroundChaiqin chengqi decoction (CQCQD) is a Chinese herbal formula derived from dachengqi decoction. CQCQD has been used for the management of acute pancreatitis (AP) in the West China Hospital for more than 30 years. Although CQCQD has a well-established clinical efficacy, little is known about its bioactive ingredients, how they interact with different therapeutic targets and the pathways to produce anti-inflammatory effects.PurposeToll-like receptor 4 (TLR4) and the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated pro-inflammatory signaling pathways, play a central role in AP in determining the extent of pancreatic injury and systemic inflammation. In this study, we screened the bioactive ingredients using a pharmacological sub-network analysis based on the TLR4/NLRP3 signaling pathways followed by experimental validation.MethodsThe main CQCQD bioactive compounds were identified by UPLC-QTOF/MS. The TLR4/NLRP3 targets in AP for CQCQD active ingredients were confirmed through a pharmacological sub-network analysis. Mice received 7 intraperitoneal injections of cerulein (50 μg/kg; hourly) to induce AP (CER-AP), while oral gavage of CQCQD (5, 10, 15 and 20 g/kg; 3 doses, 2 hourly) was commenced at the 3rd injection of cerulein. Histopathology and biochemical indices were used for assessing AP severity, while polymerase chain reaction, Western blot and immunohistochemistry analyses were used to study the mechanisms. Identified active CQCQD compounds were further validated in freshly isolated mouse pancreatic acinar cells and cultured RAW264.7 macrophages.ResultsThe main compounds from CQCQD belonged to flavonoids, iridoids, phenols, lignans, anthraquinones and corresponding glycosides. The sub-network analysis revealed that emodin, rhein, baicalin and chrysin were the compounds most relevant for directly regulating the TLR4/NLRP3-related proteins TLR4, RelA, NF-κB and TNF-α. In vivo, CQCQD attenuated the pancreatic injury and systemic inflammation of CER-AP and was associated with reduced expression of TLR4/NLRP3-related mRNAs and proteins. Emodin, rhein, baicalin and chrysin significantly diminished pancreatic acinar cell necrosis with varied effects on suppressing the expression of TLR4/NLRP3-related mRNAs. Emodin, rhein and chrysin also decreased nitric oxide production in macrophages and their combination had synergistic effects on alleviating cell death as well as expression of TLR4/NLRP3-related proteins.ConclusionsCQCQD attenuated the severity of AP at least in part by inhibiting the TLR4/NLRP3 pro-inflammatory pathways. Its active ingredients, emodin, baicalin, rhein and chrysin contributed to these beneficial effects.     

Application of “spider-web” mode in discovery and identification of Q-markers from Xuefu Zhuyu capsule

BackgroundThe selection of quality control indicators in a complex system is a key scientific issue for the study of Chinese materia medica (CMM), which is directly related to its safety and efficacy. In order to scientifically understand and control the quality of CMM, quality marker (Q-marker) has been recently raised as a new concept, which provided a novel research idea for the quality control and evaluation of CMM.PurposeBy a new and integrated “spider-web” mode, Q-markers of Xuefu Zhuyu capsule (XZC) were comprehensively uncovered, conducing to great improvement of quality control of XZC.MethodsMainly established by three dimensions derived from six variables including content, stability and activity, “spider-web” mode was constructed to evaluate Q-marker property of candidate compounds by taking regression area of the tested compounds into account.ResultsThe candidate compounds with larger regression area were preferentially adopted as Q-markers, which should possess the satisfactorily integrated properties of content, stability and activity. Six compounds, naringin, isoliquiritin, paeoniflorin, protocatechuic acid, neohesperidin and ferulic acid, were identified and preferred as Q-markers of XZC.ConclusionBased on “spider-web” mode, Q-markers from Xuefu Zhuyu capsule were successfully screened, which would substantially perform quality control of XZC and prove the feasibility of “spider-web” mode in solving the selection of quality control indicators from compound formulae.     

Quality markers based on phytochemical analysis and anti-inflammatory screening: An integrated strategy for the quality control of Dalbergia odorifera by UHPLC-Q-Orbitrap HRMS

BackgroundQuality control, key for the clinical application of traditional Chinese medicines (TCMs), should be connected to the authentication and efficacy of TCMs. The heartwood of Dalbergia odorifera has been widely used to treat inflammation-related diseases. However, in the Chinese pharmacopeia, only the total volatile oil, which does not sufficiently reflect the clinical efficacy, is used as a quality control indicator.PurposeEstablishing a “phytochemical-specificity-effectiveness-Q-marker” analytical strategy to improve the quality control of D. odorifera.MethodsCombined with biosynthetic pathway analysis, phytochemical compositions identified by UHPLC-Q-Orbitrap HRMS were used to build substantial phytochemical groups and further discover specific Q-markers. Then, lipopolysaccharide-stimulated RAW 264.7 cells were used to screen effective anti-inflammatory ingredients. Finally, a UHPLC-HRMS method was developed and validated to quantify the selected Q-markers in D. odorifera samples.ResultsAlong the constructed biosynthetic pathways, 93 phytochemical components were identified in D. odorifera, including 7 chalcones, 13 flavanones, 21 isoflavones, 21 isoflavanones, 3 flavonols, 19 neoflavones, etc. Among them, 31 compounds representing these 6 categories were further evaluated for their anti-inflammatory activities. It revealed that the extract of D. odorifera and nine flavonoids in the noncytotoxic range could alleviated lipopolysaccharide-stimulated inflammation in RAW 264.7 cells by decreasing the production of proinflammatory mediators such as nitric oxide and interleukin-6. Notably, neoflavones, as species-specific components, exhibited superior anti-inflammatory activities among the representative compounds. Finally, 12 Q-markers (butin, liquiritigenin, eriodictyol, melanettin, naringenin, butein, genistein, 4′-hydroxy-4-methoxydalbergione, isoliquiritigenin, 2,4-dihydroxy-5-methoxybenzophenone, medicarpin, and pinocembrin), which reflect specificity and effectiveness, were successfully quantified in 10 batches of samples from different origins. The origins and consistency of D. odorifera could be efficiently discriminated by hierarchical cluster analysis (HCA).ConclusionThe analysis strategy that combines phytochemical analysis with anti-inflammatory screening clarified the therapeutic material basis and discovered Q-markers, which possibly offers a more comprehensive quality assessment of D. odorifera.     

Analytical strategies for the discovery and validation of quality-markers of traditional Chinese medicine

BackgroundQuality control of traditional Chinese medicine (TCM) is the basis of clinical efficacy. Due to the complexity of TCM, it is difficult to unify the quality control, and hinders the further implementation of the quality standardization of TCM. As a new concept, quality-marker (Q-marker) plays a powerful role in promoting the standardization of quality control system of TCM.Hypothesis/PurposeThe present review aims to provide reference and scientific basis for further development of Q-marker and assist standardization of quality control of TCM.MethodsExtensive search of various documents and electronic databases such as Pubmed, Royal Society of Chemistry, Science Direct, Springer, Web of Science, and Wiley, etc., were used to search scientific contributions. Other online academic libraries, e.g. Google Scholars, Scopus and national pharmacology literature were also been employed to learn more relevant information about Q-marker.ResultsQ-markers play vital role in promoting the standardization of quality control of TCM. The factors that affect the quality of TCM, the advantages and disadvantages of the analytical techniques commonly used in Q-marker research were reviewed, as well as the systematic research strategies, which were verified by practices.ConclusionThe proposal of Q-marker not only provided a new perspective to break through the bottleneck of current quality control, but also can be used in the evaluation of pharmacological efficiency, therapeutic discovery, toxicology, etc. In addition, the Q-marker analysis strategies summarized in this paper is helpful to standardize the quality control of TCM and promote the internationalization of TCM.     

Discovery of chemical markers for identifying species,growth mode and production area of Astragali Radix by using ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry

BackgroundAstragali Radix (AR) is a well-known Chinese herbal medicine. The quality of AR can be affected by many factors such as species, growth mode and production area, but there are still no chemical markers to distinguish it.PurposeTo explore chemical markers for improving the quality assessment of AR and discover chemical markers for identifying species, growth mode and production area of AR.MethodsA highly sensitive, efficient and accurate method based on ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS) for simultaneous quantitative determination of 14 major chemical components (five flavonoids and nine triterpene saponins) in 94 batches of AR from China, Republic of Korea and Germany was developed for the first time. To explore chemical markers and assess changes in the contents of 14 compounds in the 94 batches of AR samples from different regions, hierarchical clustering analysis (HCA) and principal component analysis (PCA) were performed.ResultsAstragaloside III was not only an important chemical marker for distinguishing two species of AR, i.e.: Astragalus mongholicus and A. membranaceus, but also a potential chemical marker for the classification of cultivated and semi-wild AR. In addition, in the batches of cultivated AR, the content of isoastragaloside II and cyclocephaloside II were greater in batches from the region of Shaanxi Province than that of other Provinces in China, but the content of calycosin-7-O-β-D-glucoside and astragaloside IV, which are the quality control markers of AR required by the Chinese Pharmacopoeia, were higher than that of other Provinces in China. In addition, the content of calycosin-7-O-β-D-glucoside, ononin, calycosin and astragaloside I could be used to identify samples of AR collected from China, Republic of Korea and Germany.ConclusionThis UHPLC-QQQ-MS/MS method could be applied to the quantitative evaluation of AR and could be an important and meaningful reference to develop chemical markers for quality control of AR.     

Discovery of quality-marker ingredients of Panax quinquefolius driven by high-throughput chinmedomics approach

BackgroundQuality control of traditional Chinese medicine (TCM) has always been a hot issue to TCM. However, due to the complexity of TCM ingredients, the current quality standards of TCM have problems that are difficult to guarantee clinical efficacy. American ginseng, the dried roots of Pawajc quinquefolium L. (Araliaceae), is a valuable herbal medicine due to various pharmacological effects and huge health benefit, which are associated with numerous active ingredients such as ginsenosides. Although a large number of studies have investigated the active ingredients of American ginseng, Q-markers reflecting comprehensive review on its efficacies has yet been unrevealed.PurposeThe study aims to discover the Q-markers of Panax quinquefolius (American ginseng), provides a powerful method to clarify the significant ingredents of TCM and help further discovering extensive quality evaluation model,contributing to a significant improvement of TCM quality standard.MethodsMice general status, biochemical indexes assay, urine metabolic profile, and serum metabolic profile were utilized for model replication and efficacy evaluation. The in vitro and in vivo constituents of American ginseng using ultra-high performance liquid chromatography coupled with mass spectrometry (UPLC-MS) with Serum Pharmacochemistry of TCM were in-depth investigated. Q-markers that were associated with core markers of therapeutic effects were excavated by a plotting of correlation between marker metabolites and serum constituents (PCMS) approach.ResultsCorrelation analysis of 41 blood and urine labeled metabolites with 14 serum components showed that 24-methyl-7-cholesten-3β-ol, zizybeoside II, betulin, ginsenoside Rd, cinnamyl alcohol, pseudoginsenoside F11 is highly correlated with the therapeutic effects of Compound Zaofan Pill (CZP), while pseudoginsenoside F11 and ginsenoside Rd are highly correlated with the therapeutic effects of American ginseng. The six absorbed blood compounds can be considered as potential Q-markers for compound, of which two compounds, such as pseudoginsenoside F11 and ginsenoside Rd, can be considered as potential Q-markers for American ginseng.ConclusionThe study has demonstrated that the Chinmedomics is an effective, comprehensive and fire-new method for discovering the Q-markers of TCM, and it may be more reasonable choices to establish quality standards of TCM.     

Synthesis and anti-cancer activity evaluation of new aurone derivatives

Abstract

In this study, we have synthesized 2-[3- or 4-(2-aryl-2-oxoethoxy)arylidene]benzofuran-3-one derivatives (D1–D38) and evaluated their anti-cancer activities. The final compounds were obtained in multistep synthesis reactions using benzofuranon-3-one derivatives (A1–A4, B) as starting materials which were gained in various synthetic ways. Aurone derivatives (C1–C10) were acquired with the condensation reaction of these starting materials and 3-/4-hydroxybenzaldehyde which were then reacted with α-bromoacetophenones to get final compounds. The anti-cancer activity of the selected compounds was performed by National Cancer Institute (NCI), USA against 60 human tumor cell lines derived from nine neoplastic diseases. Compounds exhibited anti-cancer activity in varying ratios.     

Inhibition of Acid Phosphatase Isoforms Purified from Mature Soybean (Glyczne MAX) Seeds

The four soybean seed acid phosphatase isoforms AP1, AP2, AP3A and AP3B were competitively inhibited by phosphate, vanadate, fluoride and molybdate, using p-nitrophenylphos-phate as substrate. The four isoforms were not significantly affected by compounds that can interact with SH residues or by pyridoxal phosphate. These results indicated that cysteine and lysine residues are not present in the active site of the four soybean seed acid phosphatase isoforms. The inhibition constant values for phosphate, vanadate, fluoride and molybdate at pH 5.0 were respectively: API (250, 12.8, 1.7, 0.05 μM), AP2 (800,10, 500, 0.025 μM), AP3A (250, 24.2,250, 0.032 μM), AP3B (2400, 36.9,750, 0.05 μM).     

Bioactivity-guided discovery of quality control markers in rhizomes of Curcuma wenyujin based on spectrum-effect relationship against human lung cancer cells

BackgroundDue to the diversity of the ingredients, the complexity of the mechanism of action, the uncertainty of the effective ingredients, coupled with the multiple species and multiple growing areas, the quality control (QC) of Traditional Chinese Medicines (TCMs) is challenging. Discovering and identifying effective compounds from the complex extracts of TCMs and then establishing a scientific QC method is the key to the holistic QC of TCMs.PurposeTo develop an anti-lung-cancer-guided spectrum-effect relationship approach for the discovery of QC markers of the rhizome of Curcuma wenyujin (WEZ) and establish a bioactive compounds-based holistic QC method.MethodsThe chemical profiling of the volatile oil (WVO) from 42 batches of WEZ collected from different growing areas was performed by GC-MS. The anti-lung cancer activity of different WVO samples was determined by CCK-8 assay against human lung cancer cells (A549). The apoptosis and cell cycle analysis under different concentrations of WVO were detected by flow cytometry. SIMCA-P software was used to perform multivariate statistical analysis on the chemical composition of different WVO samples and to find the different components. Active compounds were screened using a PLSR model of the spectrum-effect relationship. Bioactive compounds-based fingerprint and quantification of the leading bioactive compounds were developed by GC-MS and GC-FID, respectively.ResultsSeventy-eight compounds were detected in WVO and 54 were successfully identified. The multivariate statistical analysis uncovered that WVO components and the anti-A549 activity of WVO at the concentration of 60 nl/ml differ greatly according to the origin of the plant. The WVO at the concentration of 60 nl/ml (IC₅₀) increased A549 cells apoptosis significantly with late and early apoptosis of 15.61% and 7.80%, and the number of cells in the G2/M phase were also increased significantly under this concentration. The spectrum-effect relationship analysis revealed that 44 compounds were positively correlated with their activities, and the result was verified by A549 cell viability assay. Sixteen positively correlated compounds were further selected as QC markers according to their relative amount > 0.5% and anticancer activity. Finally, the 16 QC markers-based GC-MS fingerprint was established to holistically control the quality of WEZ, and a GC-FID method was developed for the quantification of leading bioactive compounds, β-elemene and β-caryophyllene.ConclusionBased on an anti-lung-cancer-guided spectrum-effect relationship approach, the bioactive compounds-based holistic QC method was successfully developed for WEZ, which could provide a valuable reference for the QC of TCMs.     

Selectivity and potential interference from phenolic compounds in chemiluminescence methods for the determination of synephrine

Three recently reported chemiluminescence methods (based on reactions with alkaline luminol and hexacyanoferrate(III); acidic cerium(IV) and rhodamine B; and acidic permanganate with polyphosphates) for the determination of synephrine were re‐evaluated in terms of their selectivity towards this analyte in comparison to other phenolic compounds. A fourth reagent system, acidic soluble manganese(IV) and formaldehyde, was also examined. Each set of reagents was sensitive towards synephrine (limits of detection were 3 × 10^?9, 5 × 10^?8, 1 × 10^?8 and 1 × 10^?8 mol/L, respectively) but also responded with numerous other phenolic compounds, including some that are present in citrus fruit extracts, dietary supplements and/or biological fluids. It is therefore recommended that the determination of synephrine in these matrices should incorporate physical separation of sample components (e.g. chromatography or electrophoresis). In more general terms, this study illustrates that accurate percentage recoveries for an analyte in spiked samples (without validation against another analytical method) are insufficient to confirm the analytical utility of new flow‐injection analysis (FIA) procedures. Copyright © 2008 John Wiley & Sons, Ltd.     

Chemical constituents isolated from Polygala japonica leaves and their inhibitory effect on nitric oxide production in vitro

A methanolic extract of dried leaves of Polygala japonica Houtt (Polygalaceae) significantly attenuated nitric oxide production in lipopolysaccharide-simulated BV2 microglia. Five anthraquinones chrysophanol (1), emodin (2), aloe-emodin (3), emodin 8-O-β-D-glucopyranoside (4) and trihydroxy anthraquinone (5), and four flavonoids kaempferol (6), chrysoeriol (7), kaempferol 3-gentiobioside (8) and isorhamnetin (9) were isolated from the methanolic extract using bioactivity-guided fractionation. Among them, compounds 1–4, 6 and 7 showed significant inhibitory effect on lipopolysaccharide-induced nitric oxide production in BV2 microglia at the concentrations ranging from 1.0 to 100.0 μM.     

Magnolol inhibits migration of vascular smooth muscle cells via cytoskeletal remodeling pathway to attenuate neointima formation

BackgroundIncreased proliferation and migration of vascular smooth muscle cells (VSMCs) contribute importantly to the formation of both atherosclerotic and restenotic lesions. The objective of this study was to investigate the effect of magnolol on VSMC migration.MethodsThe proteolytic activity of matrix metalloproteinases (MMPs) in tumor necrosis factor alpha (TNF-α) stimulated VSMCs was performed by gelatin zymography. VSMC migration was assessed by wound healing and Boyden chamber methods. Collagen induced VSMC adhesion was determined by spectrofluorimeter and stress fibers formation was evaluated by fluorescence microscope. The expression of signaling molecules involved in stress fibers formation was determined by western blot. The phosphorylation of myosin light chain (MLC20) was determined by urea-glycerol polyacrylamide gel electrophoresis. Immunohistochemistry was performed to determine the expression of β1-integrin and collagen type I in the injured carotid arteries of rats on day 35 after vascular injury.ResultsVSMC migration was strongly inhibited by magnolol without affecting MMPs expression. Also, magnolol inhibited β1-integrin expression, FAK phosphorylation and RhoA and Cdc42 activation to inhibit the collagen induced stress fibers formation. Moreover, magnolol inhibited the phosphorylation of MLC20. Our in vivo results showed that magnolol inhibited β1-integrin expression, collagen type I deposition and FAK phosphorylation in injured carotid arteries without affecting MMP-2 activity.ConclusionsMagnolol inhibited VSMC migration via inhibition of cytoskeletal remodeling pathway to attenuate neointima formation.General significanceThis study provides a rationale for further evaluation of magnolol for the management of atherosclerosis and restenosis.     

Thrombin-based discovery strategy of bioactive-chemical quality marker combination for pollen of Typha orientalis by metabolomics coupled with chemometrics

BackgroundIt is of utmost significance to choose the bioactive components as quality markers for ensuring the effectiveness of traditional Chinese medicine (TCM). Nonetheless, some markers are able to assess effectively the quality of TCM without considering the pharmacological mechanisms and intrinsic chemical complexities.ObjectiveThis underscores the need to discover new and efficient markers which can assess both quality and mechanism of action. Herein, a strategy of bioactive-chemical quality marker combination was proposed to improve the level of the quality control of TCM by metabolomics coupled with chemometrics.MethodsA four-step plan was followed. Firstly, acquisition of metabolic features and component characterization of different batches of pollen of Typha orientalis C.Presl were performed using UHPLC-Q-TOF/MS. Secondly, the direct inhibitory effects of pollen of T. orientalis on thrombin was assessed by using chromogenic substrate method together with HPLC. Thereafter, bioactive-chemical marker combination associated with anti-thrombin segregation was screened using supervised classifiers. Finally, quantitative assay and prediction-model of selected markers were established for guarantying the quality of pollen of T. orientalis.ResultsA total of 22 compounds were annotated based on comparison with previous work from pollen of T. orientalis by UHPLC-Q-TOF/MS. Citric acid and linolenic acid inhibited the thrombin activity with IC₅₀ values, 0.52 ± 0.02 and 0.51 ± 0.02 mg/mL, respectively. A bioactive-chemical marker combination including citric acid, linolenic acid, typhaneoside, and isorhamnetin-3-O-neohesperidoside were discovered and selected as quality markers for evaluation of pollen of T. orientalis according to their capacity for inhibiting thrombin.ConclusionThe thrombin-based discovery strategy of bioactive-chemical marker combination was a powerful tool for screening the quality markers for evaluation of pollen of T. orientalis.     

毛果鱼藤化学成分及生物活性研究

为了解毛果鱼藤(Derris eriocarpa How)藤茎和根中的生物活性成分,采用柱色谱技术,从其乙酸乙酯萃取部位分离得到6个化合物,分别鉴定为:高丽槐素(1)、美迪紫檀素(2)、大黄素(3)、松脂醇(4)、(6R,9R)9-hydroxy-4-megastigmen-3-one(5)、2-methoxygliricidol(6)。这些化合物均为首次从该植物中分离得到。体外抑菌、细胞毒抑制活性测试结果表明,化合物1、2对部分肿瘤细胞株及结核分枝杆菌(H37Rv)有明显抑制活性。     

一株红树林曲霉菌Aspergillus sp.WHUF0343的次级代谢产物研究

【目的】研究分离自三亚亚龙湾红树林根系土壤的真菌Aspergillus sp. WHUF0343的次级代谢产物及其生物活性。【方法】利用硅胶柱层析、Sephadex LH-20凝胶柱层析和半制备高效液相色谱等技术对该菌的发酵产物进行分离纯化;综合利用核磁共振波谱(NMR)和质谱(MS)等现代波谱技术以及与文献数据对照确定化合物的结构;分别采用肉汤微量稀释检测法和MTS法对化合物进行抗菌和肿瘤细胞毒活性测试。【结果】从真菌Aspergillus sp.WHUF0343的发酵产物共分离并鉴定了10个化合物,分别为isoechinulin A (1)、neoechinulin A (2)、neoechinulin E (3)、preechinulin (4)、neoechinulin D (5)、variecolorin J (6)、dehydroechinulin (7)、questinol (8)、emodin (9)和catenarin (10)。活性评价显示化合物2、9和10对幽门螺杆菌(Helicobacter pylori)和金黄色葡萄球菌(Staphylococcus aure...     

Effects of andrographolide and 14-deoxy-11,12-didehydroandrographolide on cultured primary astrocytes and PC12 cells

AimsTo test the effects of andrographolide (AP1) and 14-deoxy-11,12-didehydroandrographolide (AP2) on pheochromocytoma cell line 12 (PC12) cells in an astrocyte-rich environment.Main methodsThe abilities of AP1 and AP2 to reduce the secretion of pro-inflammatory cytokines Interleukin (IL)-1, IL-6, and Tumor necrosis factor (TNF)-α from stimulated astrocytes were tested. In addition, the abilities of AP1 and AP2 to reduce oxidative stress in astrocytes were tested using an oxidative-sensitive fluorescent dye. The reduction of chondroitin sulfate proteoglycan (CSPG) in stimulated astrocytes was tested using the dot blot method. Reduction of H₂O₂-induced death was tested in PC12 cells. Astrocyte-conditioned medium (ACM) and TNF-α-stimulated astrocyte-conditioned medium (SACM) were used to assess the effects of AP2 on PC12 cells treated with H₂O₂.Key findingsAP1 and AP2 reduced pro-inflammatory cytokines, reactive oxygen species (ROS), and CSPG in TNF-α stimulated astrocytes. AP1 protected H₂O₂-treated PC12 cells cultured in ACM. Co-incubation of PC12 cells in H₂O₂, and ACM collected from AP1 treated astrocytes did not prevent cell death.SignificanceAP1 and AP2 effectively ameliorated astrocytic pro-inflammatory reactions and prevented PC12 cell death with different efficacies. These compounds may be candidates for treatment of spinal-cord injury and neurodegeneration.