Neuropharmacologic Approaches to Restore the Brain's Microenvironment

A Broad Application of CRISPR Cas9 in Infectious, Inflammatory and Neurodegenerative Diseases

Being the most important immune-responsive cell type of the CNS, microglia always glorify the so-called crossroad of Neurology, Immunology and Pharmacology. As microglial activation is a hallmark of different neurodegenerative disorders including Alzheimer's disease (AD), Parkinson's disease (PD), HIV-associated neurocognitive disorders (HAND), Amyotrophic lateral sclerosis (ALS), etc., selective targeting of microglial cell signaling may be a valid option to control these neurodegenerative disorders with lesser side effects. This is particularly important as no effective therapies are available against these diseases and available neuroimmune modulators are known to target multiple cell types in a non-cell-specific manner. How we can achieve such specificity? A newly-developed cutting-edge molecular biology tool is rocking biomedical research in recent years so much so that it has already come under major lawsuits between the University of California Berkeley and the MIT-Harvard Broad Institute regarding its ownership rights, probably halting the Nobel committee to announce the most coveted prize to its owners. It is none other than Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR). In nutshell, the Cas9 enzyme has been paired with the bacterial immune system, CRISPR, to ultimately turn CRISPR/Cas9 as an effective genome editor. Therefore, this special issue has been devoted to highlight some of the recent discoveries on CRISPR/Cas9 in neurodegenerative disorders and explain these discoveries in the light of neuroimmune pharmacology.

Anti-glycation, anti-hemolysis, and ORAC activities of demethylcurcumin and tetrahydroxycurcumin in vitro and reductions of oxidative stress in D-galactose-induced BALB/c mice in vivo

BACKGROUND

There were few report concerning anti-glycation and antioxidant activities of the minor amounts of components in curcuminoids, demethylcurcumin and tetrahydroxycurcumin, in vitro and in vivo.

RESULTS

The bovine serum albumin/galactose of non-enzymatic glycation models, radical-induced hemolysis, and oxygen radical absorbance capacity (ORAC) were studied in vitro, and the D-galactose-induced oxidative stress in BALB/c mice and then demethylcurcumin or tetrahydroxycurcumin interventions in vivo. The parameters of oxidative stress in plasma and brain extracts were determined among animal groups with or without both curcuminoids interventions. The demethylcurcumin and tetrahydroxycurcumin exhibited anti-glycation, anti-hemolysis, and ORAC activities, and showed much better and significant difference (P < 0.05) compared to those of curcumin in vitro. In animal experiments, the intervened two curcuminoids at both concentrations showed to lower serum malondialdehyde (MDA), brain MDA levels and iNOS protein expressions, and elevate serum ORAC activities, and showed difference (P < 0.05) compared to the galactose-induced control.

CONCLUSION

The demethylcurcumin and tetrahydroxycurcumin showed potentials in developing functional foods for antioxidant-related purposes.

Cerebral Hypoperfusion and Other Shared Brain Pathologies in Ischemic Stroke and Alzheimer's Disease

Newly emerged evidence reveals that ischemic stroke and Alzheimer's disease (AD) share pathophysiological changes in brain tissue including hypoperfusion, oxidative stress, immune exhaustion, and inflammation. A mechanistic link between hypoperfusion and amyloid β accumulation can lead to cell damage as well as to motor and cognitive deficits. This review will discuss decreased cerebral perfusion and other related pathophysiological changes common to both ischemic stroke and AD, such as vascular damages, cerebral blood flow alteration, abnormal expression of amyloid β and tau proteins, as well as behavioral and cognitive deficits. Furthermore, this review highlights current treatment options and potential therapeutic targets that warrant further investigation.

HIV and the Macrophage: From Cell Reservoirs to Drug Delivery to Viral Eradication

Macrophages serve as host cells, inflammatory disease drivers and drug runners for human immunodeficiency virus infection and treatments. Low-level viral persistence continues in these cells in the absence of macrophage death. However, the cellular microenvironment changes as a consequence of viral infection with aberrant production of pro-inflammatory factors and promotion of oxidative stress. These herald viral spread from macrophages to neighboring CD4⁺ T cells and end organ damage. Virus replicates in tissue reservoir sites that include the nervous, pulmonary, cardiovascular, gut, and renal organs. However, each of these events are held in check by antiretroviral therapy. A hidden and often overlooked resource of the macrophage rests in its high cytoplasmic nuclear ratios that allow the cell to sense its environment and rid it of the cellular waste products and microbial pathogens it encounters. These phagocytic and intracellular killing sensing mechanisms can also be used in service as macrophages serve as cellular carriage depots for antiretroviral nanoparticles and are able to deliver medicines to infectious disease sites with improved therapeutic outcomes. These undiscovered cellular functions can lead to reductions in persistent infection and may potentially facilitate the eradication of residual virus to eliminate disease.

Hispolon Suppresses LPS- or LTA-Induced iNOS/NO Production and Apoptosis in BV-2 Microglial Cells

Hispolon (HIS) is an active polyphenol compound derived from Phellinus linteus (Berkeley & Curtis), and our previous study showed that HIS effectively inhibited inflammatory responses in macrophages [Yang, L.Y., S.C. Shen, K.T. Cheng, G.V. Subbaraju, C.C. Chien and Y.C. Chen. Hispolon inhibition of inflammatory apoptosis through reduction of iNOS/NO production via HO-1 induction in macrophages. J. Ethnopharmacol. 156: 61-72, 2014]; however, its effect on neuronal inflammation is still undefined. In this study, HIS concentration- and time-dependently inhibited lipopolysaccharide (LPS)- and lipoteichoic acid (LTA)-induced inducible nitric oxide (NO) synthase (iNOS)/NO production with increased heme oxygenase (HO)-1 proteins in BV-2 microglial cells. Accordingly, HIS protected BV-2 cells from LPS- or LTA-induced apoptosis, characterized by decreased DNA ladder formation, and caspase-3 and poly(ADP ribose) polymerase (PARP) protein cleavage in BV-2 cells. Similarly, the NOS inhibitor, N-nitro-L-arginine methyl ester (NAME), inhibited LPS- or LTA-induced apoptosis of BV-2 cells, but neither NAME nor HIS showed any inhibition of NO production or cell death induced by the NO donor, sodium nitroprusside (SNP), indicating the involvement of NO in the inflammatory apoptosis of microglial cells. Activation of c-Jun N-terminal kinase (JNK) and nuclear factor (NF)-[Formula: see text]B contributed to LPS- or LTA-induced iNOS/NO production and apoptosis of BV-2 cells, and that was suppressed by HIS. Additionally, HIS possesses activity to induce HO-1 protein expression via activation of extracellular signal-regulated kinase (ERK) in BV-2 cells, and application of the HO inhibitor, tin protoporphyrin (SnPP), or knockdown of HO-1 protein by HO-1 small interfering (si)RNA significantly reversed HIS inhibition of NO production and cell death in BV-2 cells stimulated by LPS. Results of an analysis of the effects of HIS and two structurally related chemicals, i.e. dehydroxy-HIS (D-HIS) and HIS-methyl ester (HIS-ME), showed that HIS expressed the most potent inhibitory effects on iNOS/NO production, JNK activation, and apoptosis in BV-2 microglial cells activated by LPS with increased HO-1 protein expression. Overall these results suggested that HIS possesses inhibitory activity against LPS- or LTA-induced inflammatory responses including iNOS/NO production and apoptosis in BV-2 microglial cells and that the mechanisms involve upregulation of the HO-1 protein and downregulation of JNK/NF-[Formula: see text]B activation. A critical role of hydroxyl at position C3 in the anti-inflammatory actions of HIS against activated BV-2 microglial cells was suggested.

Nucleotide transmitters ATP and ADP mediate intercellular calcium wave communication via P2Y12/13 receptors among BV-2 microglia

Nerve injury is accompanied by a liberation of diverse nucleotides, some of which act as ‘find/eat-me’ signals in mediating neuron-glial interplay. Intercellular Ca²⁺ wave (ICW) communication is the main approach by which glial cells interact and coordinate with each other to execute immune defense. However, the detailed mechanisms on how these nucleotides participate in ICW communication remain largely unclear. In the present work, we employed a mechanical stimulus to an individual BV-2 microglia to simulate localized injury. Remarkable ICW propagation was observed no matter whether calcium was in the environment or not. Apyrase (ATP/ADP-hydrolyzing enzyme), suramin (broad-spectrum P2 receptor antagonist), 2-APB (IP₃ receptor blocker) and thapsigargin (endoplasmic reticulum calcium pump inhibitor) potently inhibited these ICWs, respectively, indicating the dependence of nucleotide signals and P2Y receptors. Then, we detected the involvement of five naturally occurring nucleotides (ATP, ADP, UTP, UDP and UDP-glucose) by desensitizing receptors. Results showed that desensitization with ATP and ADP could block ICW propagation in a dose-dependent manner, whereas other nucleotides had little effect. Meanwhile, the expression of P2Y receptors in BV-2 microglia was identified and their contributions were analyzed, from which we suggested P2Y_12/13 receptors activation mostly contributed to ICWs. Besides, we estimated that extracellular ATP and ADP concentration sensed by BV-2 microglia was about 0.3 μM during ICWs by analyzing calcium dynamic characteristics. Taken together, these results demonstrated that the nucleotides ATP and ADP were predominant signal transmitters in mechanical stimulation-induced ICW communication through acting on P2Y_12/13 receptors in BV-2 microglia.

Promoting Global Health - Prevention and Treatment of Substance Abuse and HIV in Asia

This special issue contains 20 papers including 3 Perspectives, 1 Brief Report, 6 Invited Reviews, and 10 Original Articles, which highlight the work by presenters at the second meeting of the biennial Conference Series to Promote Global Health held on April 22-24, 2015 in Hangzhou, Zhejiang, China. These papers focused on the prevalent substance misuse of amphetamine-type-stimulants and opioids, and the increasing prevalence of HIV-infection in Asian countries. The Conference Series is sponsored by the National Institute on Drug Abuse of the U.S. National Institutes of Health, with the goal of exchanging knowledge and ideas related to, and promoting international collaborative work on, the prevention and treatment of substance use disorders and HIV-infection, in order to promote health in Asian and Pacific Islanders and other populations.