Ginkgolide B Protects Against Ischemic Stroke Via Modulating Microglia Polarization in Mice

DCPIB Attenuates Ischemia-Reperfusion Injury by Regulating Microglial M1/M2 Polarization and Oxidative Stress

The inflammatory response plays an indispensable role in ischemia-reperfusion injury, the most significant of which is the inflammatory response caused by microglial polarization. Anti-inflammatory therapy is also an important remedial measure after failed vascular reconstruction. Maintaining the internal homeostasis of the brain is a crucial measure for suppressing the inflammatory response. The mechanism underlying the relationship between DCPIB, a selective blocker of volume-regulated anion channels (VRAC), and inflammation induced by cerebral ischemia-reperfusion injury is currently unclear. The purpose of this study was to investigate the relationship between DCPIB and microglial M1/M2 polarization-mediated inflammation after cerebral ischemia-reperfusion injury. C57BL/6 mice were subjected to transient middle cerebral artery occlusion (tMCAO). DCPIB was administered by a lateral ventricular injection within 5 min after reperfusion. Behavioral assessments were conducted at 1, 3, and 7 days after tMCAO/R. Pathological injuries were evaluated using TTC assay, HE and Nissl staining, brain water content measurement, and immunofluorescence staining. The levels of inflammatory cytokines were analyzed using qPCR and ELISA. Additionally, the phenotypic variations of microglia were examined using immunofluorescence staining. In mouse tMCAO/R model, DCPIB administration markably reduced mortality, improved behavioral performance, and alleviated pathological injury. DCPIB treatment significantly inhibited the inflammatory response, promoted the conversion of M1 microglia to M2 microglia via the MAPK signaling pathway, and ultimately protected neurons from the microglia-mediated inflammatory response. In addition, DCPIB inhibited oxidative stress induced by cerebral ischemia-reperfusion injury. In conclusion, DCPIB attenuates cerebral ischemia-reperfusion injury by regulating microglial M1/M2 polarization and oxidative stress.

Ginkgolide B can alleviate spinal cord glymphatic system dysfunction and provide neuroprotection in painful diabetic neuropathy rats by inhibiting matrix metalloproteinase-9

The glymphatic system plays a crucial role in maintaining optimal central nervous system (CNS) function by facilitating the removal of metabolic wastes. Aquaporin-4 (AQP4) protein, predominantly located on astrocyte end-feet, is a key pathway for metabolic waste excretion. β-Dystroglycan (β-DG) can anchor AQP4 protein to the end-feet membrane of astrocytes and can be cleaved by matrix metalloproteinase (MMP)-9 protein. Studies have demonstrated that hyperglycemia upregulates MMP-9 expression in the nervous system, leading to neuropathic pain. Ginkgolide B (GB) exerts an inhibitory effect on the MMP-9 protein. In this study, we investigated whether inhibition of MMP-9-mediated β-DG cleavage by GB is involved in the regulation of AQP4 polarity within the glymphatic system in painful diabetic neuropathy (PDN) and exerts neuroprotective effects. The PDN model was established by injecting streptozotocin (STZ). Functional changes in the glymphatic system were observed using magnetic resonance imaging (MRI). The paw withdrawal threshold (PWT) was measured to assess mechanical allodynia. The protein expressions of MMP-9, β-DG, and AQP4 were detected by Western blotting and immunofluorescence. Our findings revealed significant decreases in the efficiency of contrast agent clearance within the spinal glymphatic system of the rats, accompanied by decreased PWT, increased MMP-9 protein expression, decreased β-DG protein expression, and loss of AQP4 polarity. Notably, GB treatment demonstrated the capacity to ameliorate spinal cord glymphatic function by modulating AQP4 polarity through MMP-9 inhibition, offering a promising therapeutic avenue for PDN.

The Roles of RhoA/ROCK/NF-κB Pathway in Microglia Polarization Following Ischemic Stroke

Ischemic stroke is the leading cause of death and disability worldwide. Nevertheless, there still lacks the effective therapies for ischemic stroke. Microglia are resident macrophages of the central nervous system (CNS) and can initiate immune responses and monitor the microenvironment. Microglia are activated and polarize into proinflammatory or anti‑inflammatory phenotype in response to various brain injuries, including ischemic stroke. Proinflammatory microglia could generate immunomodulatory mediators, containing cytokines and chemokines, these mediators are closely associated with secondary brain damage following ischemic stroke. On the contrary, anti-inflammatory microglia facilitate recovery following stroke. Regulating the activation and the function of microglia is crucial in exploring the novel treatments for ischemic stroke patients. Accumulating studies have revealed that RhoA/ROCK pathway and NF-κB are famous modulators in the process of microglia activation and polarization. Inhibiting these key modulators can promote the polarization of microglia to anti-inflammatory phenotype. In this review, we aimed to provide a comprehensive overview on the role of RhoA/ROCK pathway and NF-κB in the microglia activation and polarization, reveal the relationship between RhoA/ROCK pathway and NF-κB in the pathological process of ischemic stroke. In addition, we likewise discussed the drug modulators targeting microglia polarization.

Mobilizing endogenous neuroprotection: the mechanism of the protective effect of acupuncture on the brain after stroke

Given its high morbidity, disability, and mortality rates, ischemic stroke (IS) is a severe disease posing a substantial public health threat. Although early thrombolytic therapy is effective in IS treatment, the limited time frame for its administration presents a formidable challenge. Upon occurrence, IS triggers an ischemic cascade response, inducing the brain to generate endogenous protective mechanisms against excitotoxicity and inflammation, among other pathological processes. Stroke patients often experience limited recovery stages. As a result, activating their innate self-protective capacity [endogenous brain protection (EBP)] is essential for neurological function recovery. Acupuncture has exhibited clinical efficacy in cerebral ischemic stroke (CIS) treatment by promoting the human body's self-preservation and "Zheng Qi" (a term in traditional Chinese medicine (TCM) describing positive capabilities such as self-immunity, self-recovery, and disease prevention). According to research, acupuncture can modulate astrocyte activity, decrease oxidative stress (OS), and protect neurons by inhibiting excitotoxicity, inflammation, and apoptosis via activating endogenous protective mechanisms within the brain. Furthermore, acupuncture was found to modulate microglia transformation, thereby reducing inflammation and autoimmune responses, as well as promoting blood flow restoration by regulating the vasculature or the blood-brain barrier (BBB). However, the precise mechanism underlying these processes remains unclear. Consequently, this review aims to shed light on the potential acupuncture-induced endogenous neuroprotective mechanisms by critically examining experimental evidence on the preventive and therapeutic effects exerted by acupuncture on CIS. This review offers a theoretical foundation for acupuncture-based stroke treatment.

Thymoquinone regulates microglial M1/M2 polarization after cerebral ischemia-reperfusion injury via the TLR4 signaling pathway

Acute ischemic stroke followed by microglia activation, and the regulation of neuroinflammatory responses after ischemic injury involves microglia polarization. microglia polarization is involved in the regulation of neuroinflammatory responses and ischemic stroke-related brain damage. Thymoquinone (TQ) is an anti-inflammatory agent following ischemic stroke onset. However, the significance of TQ in microglia polarization following acute ischemic stroke is still unclear. We predicted that TQ might have neuroprotective properties by modulating microglia polarization. In this work, we mimicked the clinical signs of acute ischemic stroke using a mouse middle cerebral artery ischemia-reperfusion (I/R) model. It was discovered that TQ treatment decreased I/R-induced infarct volume, cerebral oedema, and promoted neuronal survival, as well as improved the histopathological changes of brain tissue. The sensorimotor function was assessed by the Garica score, foot fault test, and corner test, and it was found that TQ could improve the motor deficits caused by I/R. Secondly, real-time fluorescence quantitative PCR, immuno-fluorescence, ELISA, and western blot were used to detect the expression of M1/M2-specific markers in microglia to explore the role of TQ in the modulation of microglial cell polarization after cerebral ischemia-reperfusion. We found that TQ was able to promote the polarization of microglia with extremely secreted inflammatory factors from M1 type to M2 type. Furthermore, TQ could block the TLR4/NF-κB signaling pathway via Hif-1α activation which subsequently may attenuate microglia differentiation following the cerebral ischemia, establishing a mechanism for the TQ's beneficial effects in the cerebral ischemia-reperfusion model.

Understanding exosomes: Part 2-Emerging leaders in regenerative medicine

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with the ability to communicate with other tissues and cell types over long distances. Their use in regenerative medicine has gained tremendous momentum recently due to their ability to be utilized as therapeutic options for a wide array of diseases/conditions. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be developed. Today exosomes have been applied in numerous contexts including neurodegenerative disorders (Alzheimer's disease, central nervous system, depression, multiple sclerosis, Parkinson's disease, post-traumatic stress disorders, traumatic brain injury, peripheral nerve injury), damaged organs (heart, kidney, liver, stroke, myocardial infarctions, myocardial infarctions, ovaries), degenerative processes (atherosclerosis, diabetes, hematology disorders, musculoskeletal degeneration, osteoradionecrosis, respiratory disease), infectious diseases (COVID-19, hepatitis), regenerative procedures (antiaging, bone regeneration, cartilage/joint regeneration, osteoarthritis, cutaneous wounds, dental regeneration, dermatology/skin regeneration, erectile dysfunction, hair regrowth, intervertebral disc repair, spinal cord injury, vascular regeneration), and cancer therapy (breast, colorectal, gastric cancer and osteosarcomas), immune function (allergy, autoimmune disorders, immune regulation, inflammatory diseases, lupus, rheumatoid arthritis). This scoping review is a first of its kind aimed at summarizing the extensive regenerative potential of exosomes over a broad range of diseases and disorders.

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases (CVDs), the world's primary cause of death. Ginkgo biloba , a well-known traditional Chinese medicine with notable cardiovascular actions, has been used as a cardio- and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries. Preclinical studies have shown that ginkgolide B, a bioactive component in Ginkgo biloba , can ameliorate atherosclerosis in cultured vascular cells and disease models. Of clinical relevance, several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases, such as ischemia stroke. Here, we present a comprehensive review of the pharmacological activities, pharmacokinetic characteristics, and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy. We highlight new molecular targets of ginkgolide B, including nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidase), lectin-like oxidized LDL receptor-1 (LOX-1), sirtuin 1 (SIRT1), platelet-activating factor (PAF), proprotein convertase subtilisin/kexin type 9 (PCSK9) and others. Finally, we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

Potential regulatory effects of stem cell exosomes on inflammatory response in ischemic stroke treatment

The high incidence and disability rates of stroke pose a heavy burden on society. Inflammation is a significant pathological reaction that occurs after an ischemic stroke. Currently, therapeutic methods, except for intravenous thrombolysis and vascular thrombectomy, have limited time windows. Mesenchymal stem cells (MSCs) can migrate, differentiate, and inhibit inflammatory immune responses. Exosomes (Exos), which are secretory vesicles, have the characteristics of the cells from which they are derived, making them attractive targets for research in recent years. MSC-derived exosomes can attenuate the inflammatory response caused by cerebral stroke by modulating damage-associated molecular patterns. In this review, research on the inflammatory response mechanisms associated with Exos therapy after an ischemic injury is discussed to provide a new approach to clinical treatment.

Targeting p53 for neuroinflammation: New therapeutic strategies in ischemic stroke

Ischemic stroke (IS) is characterized by high incidence, high recurrence, and high mortality and places a heavy burden on society and families. The pathological mechanisms of IS are complex, among which secondary neurological impairment mediated by neuroinflammation is considered to be the main factor in cerebral ischemic injury. At present, there is still a lack of specific therapies to treat neuroinflammation. The tumor suppressor protein p53 has long been regarded as a key substance in the regulation of the cell cycle and apoptosis in the past. Recently, studies have found that p53 also plays an important role in neuroinflammatory diseases, such as IS. Therefore, p53 may be a crucial target for the regulation of the neuroinflammatory response. Here, we provide a comprehensive review of the potential of targeting p53 in the treatment of neuroinflammation after IS. We describe the function of p53, the major immune cells involved in neuroinflammation, and the role of p53 in inflammatory responses mediated by these cells. Finally, we summarize the therapeutic strategies of targeting p53 in regulating the neuroinflammatory response after IS to provide new directions and ideas for the treatment of ischemic brain injury.

Antiplatelet effect of ginkgo diterpene lactone meglumine injection in acute ischemic stroke: A randomized, double-blind, placebo-controlled clinical trial

This study was designed to evaluate antiplatelet effect and therapeutic effect of ginkgo diterpene lactone meglumine injection (GDLI) in acute ischemic stroke (AIS) patients. In this randomized, double-blind, placebo-controlled trial, we randomly assigned 70 inpatients within 48 hr after the onset of AIS to combination therapy with GDLI and aspirin (GDLI at a dose of 25 mg/d for 14 days plus aspirin at a dose of 100 mg/d for 90 days) or to placebo plus aspirin in a ratio of 1:1. Platelet function, the National Institute of Health Stroke Scale (NIHSS), and the modified Rankin Scale (mRS) were evaluated. A good outcome was defined as NIHSS scores decrease ≥5 or mRS scores decrease ≥2. Results showed that arachidonic acid induced maximum platelet aggregation rate (AA-MAR) and mean platelet volume (MPV) of the GDLI-aspirin group were much lower than that of the aspirin group (p = 0.013 and p = 0.034, respectively) after the 14-day therapy. The combination of GDLI and aspirin was superior to aspirin alone, and had significant impact on the good outcome at day 90 (ORadj 7.21 [95%CI, 1.03-50.68], p = 0.047). In summary, GDLI has antiplatelet effect and can improve the prognosis of AIS patients.

Resveratrol alleviated neuroinflammation induced by pseudorabies virus infection through regulating microglial M1/M2 polarization

BACKGROUND

Pseudorabies virus (PRV) infections in susceptible non-porcine species trigger uncontrolled inflammations and eventually fatal encephalitis. Resveratrol (Res) has broad pharmacological functions including anti-virus, anti-inflammation, and neuroprotective.

PURPOSE

We attempted to investigate the potential of Res in ameliorating PRV infection pathology in mice and decipher the mechanism of Res in treating PRV.

METHODS

The mice were infected by PRV to investigate the protective effect of Res. Blood-brain barrier (BBB) permeability, H&E/Nissl/TUNEL staining, Real-time PCR and ELISA analyses were performed. Primary microglia and neuron were isolated from mice and cultured. The co-culture model of microglia and neuron was established by transwell. Immunofluorescence assay and flow cytometry were used.

RESULTS

In this study, we showed that Res ameliorated brain damage by reducing BBB permeability in PRV-infected mice, and diminished the expressions of MMP-2, MMP-9 and ZO-1 in the cortex. Pathological changes of neurons by H&E/Nissl/TUNEL staining suggested that Res could alleviate neuronal lesions. Moreover, Res inhibited the expressions of pro-inflammatory factors (IL-6, TNF-α) and chemokines (CCL3, CXCL10, MCP-1), but increased the expressions of anti-inflammatory factors (IL-4, IL-10) and neurotrophic factor (TGF-β, NGF and GDNF) in brain. In vitro cultured microglia cells, Res could suppress M1 microglia polarization and activate M2 microglia polarization. Co-culture of PRV-infected microglia with neuron cells by transwell system indicated that Res alleviated inflammatory response and neuronal apoptosis.

CONCLUSION

This study provided evidence that Res could protect mice from PRV-induced encephalitis through regulation of microglia polarization and neuronal apoptosis suggesting the potential for treatment of viral encephalitis.

Neuroinflammation and brain-peripheral interaction in ischemic stroke: A narrative review

Excessive immune activation within the lesion site can be observed after stroke onset. Such neuroinflammation within the brain parenchyma represents the innate immune response, as well as the result of the additional interactions between peripheral and resident immune cells. Accumulative studies have illustrated that the pathological process of ischemic stroke is associated with resident and peripheral immunity. The infiltration of peripheral immune cells within the brain parenchyma implicitly contributes to secondary brain injuries. Therefore, better understanding of the roles of resident and peripheral immune reactions toward ischemic insult is necessary. In this review, we summarized the interaction between peripheral and resident immunity on systemic immunity and the clinical outcomes after stroke onset and also discussed various potential immunotherapeutic strategies.

The role of traditional herbal medicine for ischemic stroke: from bench to clinic-A critical review

BACKGROUND

Ischemic stroke (IS) is a leading cause of death and severe long-term disability worldwide. Over the past few decades, considerable progress has been made in anti-ischemic therapies. However, IS remains a tremendous challenge, with favourable clinical outcomes being generally difficult to achieve from candidate drugs in preclinical phase testing. Traditional herbal medicine (THM) has been used to treat stroke for over 2,000 years in China. In modern times, THM as an alternative and complementary therapy have been prescribed in other Asian countries and have gained increasing attention for their therapeutic effects. These millennia of clinical experience allow THM to be a promising avenue for improving clinical efficacy and accelerating drug discovery.

PURPOSE

To summarise the clinical evidence and potential mechanisms of THMs in IS.

METHODS

A comprehensive literature search was conducted in seven electronic databases, including PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, the Chinese National Knowledge Infrastructure, the VIP Information Database, the Chinese Biomedical Literature Database, and the Wanfang Database, from inception to 17 June 2022 to examine the efficacy and safety of THM for IS, and to investigate experimental studies regarding potential mechanisms.

RESULTS

THM is widely prescribed for IS alone or as adjuvant therapy. In clinical trials, THM is generally administered within 72 h of stroke onset and are continuously prescribed for over 3 months. Compared with Western medicine (WM), THM combined with routine WM can significantly improve neurological function defect scores, promote clinical total effective rate, and accelerate the recovery time of stroke with fewer adverse effects (AEs). These effects can be attributed to multiple mechanisms, mainly anti-inflammation, antioxidative stress, anti-apoptosis, brain blood barrier (BBB) modulation, inhibition of platelet activation and thrombus formation, and promotion of neurogenesis and angiogenesis.

CONCLUSIONS

THM may be a promising candidate for IS management to guide clinical applications and as a reference for drug development.

Neuroprotective Strategies for Stroke by Natural Products: Advances and Perspectives

Cerebral ischemic stroke is a disease with high prevalence and incidence. Its management focuses on rapid reperfusion with intravenous thrombolysis and endovascular thrombectomy. Both therapeutic strategies reduce disability, but the therapy time window is short, and the risk of bleeding is high. Natural products (NPs) have played a key role in drug discovery, especially for cancer and infectious diseases. However, they have made little progress in clinical translation and pose challenges to the treatment of stroke. Recently, with the investigation of precise mechanisms in cerebral ischemic stroke and the technological development of NP-based drug discovery, NPs are addressing these challenges and opening up new opportunities in cerebral stroke. Thus, in this review, we first summarize the structure and function of diverse NPs, including flavonoids, phenols, terpenes, lactones, quinones, alkaloids, and glycosides. Then we propose the comprehensive neuroprotective mechanism of NPs in cerebral ischemic stroke, which involves complex cascade processes of oxidative stress, mitochondrial damage, apoptosis or ferroptosis-related cell death, inflammatory response, and disruption of the blood-brain barrier (BBB). Overall, we stress the neuroprotective effect of NPs and their mechanism on cerebral ischemic stroke for a better understanding of the advances and perspective in NPs application that may provide a rationale for the development of innovative therapeutic regimens in ischemic stroke.

Ginkgolide B improved postoperative cognitive dysfunction by inhibiting microgliosis-mediated neuroinflammation in the hippocampus of mice

Background

Postoperative cognitive dysfunction (POCD) are a common complication of the central nervous system following surgery and anesthesia. The specific pathogenesis and effective therapeutics of POCD need to be further studied. Ginkgolide B (GB), a platelet-activating factor receptor-specific antagonist, has been suggested to have strong anti-inflammatory effects. Here we tested the effects and mechanism of GB on POCD of aged rats.

Methods

Neurobehavioral tests were used to investigate the effect of GB pretreatment on POCD. The hippocampus were harvested to test the expression of proinflammatory cytokines by ELISA. The expression of the microglial marker ionized calcium-binding adaptor molecule-1 (Iba-1) in the hippocampus was evaluated by western blot assay and immunohistochemistry. A Nissl staining experiment was used to detect the neuronal numbers in the hippocampus.

Results

Surgery might result in the overexpression of platelet activating factor (PAF) in the plasma and hippocampus and might cause hippocampus-dependent memory impairment. GB pretreatment, inhibited the activation of microglia, reduced the levels of IL-1β and TNF-α, decreased the loss of neurons after surgery, and prevented POCD in aged rats.

Conclusion

Our findings suggested that PAF was involved in the development of POCD. Improvement of POCD by PAF antagonist GB was associated with the inhibition of microgliosis-mediated neuroinflammation and neuronal apoptosis in aged rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01750-1.

Ginkgolide B Protects Against Ischemic Stroke via Targeting AMPK/PINK1

Introduction: Ginkgolide B (GB), which is an active constituent derived from Ginkgo biloba leaves, has been reported to ameliorate Alzheimer’s disease (AD), ischemic stroke, as well as other neurodegenerative diseases due to its viable immunosuppressive and anti-inflammatory functions. However, it has yet to be proven whether GB inhibits neuronal apoptosis in ischemic stroke.

Methods: In the present research, the inhibition function of GB on neuronal apoptosis and its underpinning process(s) after cerebral ischemia were studied through transient middle cerebral artery occlusion (t-MCAO) in an in vivo rat model as well as in cultured SH-SY5Y cells subjected to oxygen and glucose deprivation (OGD)/reoxygenation in vitro. The neurological score was calculated and Nissl and TUNEL staining were performed to evaluate the stroke outcome, neuronal loss, and neuronal apoptosis. Subsequently, the western blot was utilized to detect Bcl2 and p-AMPK/AMPK expression.

Results: Compared to t-MCAO rats, rats receiving GB treatment showed a significant reduction of neuronal loss and apoptosis and improved neurological behavior at 72 h after MCAO. GB treatment also upregulated the expression of Bcl2 and p-AMPK. In vitro, GB suppressed the apoptosis in OGD/reoxygenation-challenged neuronal SH-SY5Y cells through AMPK activation.

Conclusions: Our observations suggest that GB enhanced AMPK activation in neural cells, reducing neuronal apoptosis, thus eventually preventing ischemic stroke.

The Translational Potential of Microglia and Monocyte-Derived Macrophages in Ischemic Stroke

The immune response to ischemic stroke is an area of study that is at the forefront of stroke research and presents promising new avenues for treatment development. Upon cerebral vessel occlusion, the innate immune system is activated by danger-associated molecular signals from stressed and dying neurons. Microglia, an immune cell population within the central nervous system which phagocytose cell debris and modulate the immune response via cytokine signaling, are the first cell population to become activated. Soon after, monocytes arrive from the peripheral immune system, differentiate into macrophages, and further aid in the immune response. Upon activation, both microglia and monocyte-derived macrophages are capable of polarizing into phenotypes which can either promote or attenuate the inflammatory response. Phenotypes which promote the inflammatory response are hypothesized to increase neuronal damage and impair recovery of neuronal function during the later phases of ischemic stroke. Therefore, modulating neuroimmune cells to adopt an anti-inflammatory response post ischemic stroke is an area of current research interest and potential treatment development. In this review, we outline the biology of microglia and monocyte-derived macrophages, further explain their roles in the acute, subacute, and chronic stages of ischemic stroke, and highlight current treatment development efforts which target these cells in the context of ischemic stroke.

Local Administration of Ginkgolide B Using a Hyaluronan-Based Hydrogel Improves Wound Healing in Diabetic Mice

The delayed and incomplete healing of diabetic wounds remains a major concern of global healthcare. The complex biological processes within the diabetic wound, such as chronic inflammation, impaired blood vessel growth and immature collagen remodeling, dramatically cause the failure of current treatments. Thus, emerging therapeutic strategies are highly desirable. Ginkgolide B (GB, a natural product extracted from the leaves of Ginkgo biloba L.) has been applied in the treatment of cerebrovascular and cardiovascular disorders, which is mainly due to the anti-oxidative, anti-inflammatory and proliferative effects. In this study, the role of GB in facilitating the anti-inflammatory and pro-healing effects on diabetic wounds was for the first time confirmed using in vitro, ex vivo and in vivo experimental methods. As a consequence, GB was able to significantly achieve the activities of anti-inflammation, re-epithelialization, and pro-angiogenesis. Previously, a hydrogel has been developed using the high molecular weight hyaluronan (hyaluronic acid, HA) in our laboratory. In this study, this hydrogel was utilized in vivo for local administration of GB to the full-thickness wounds of diabetic mice. The resultant hydrogel formulation (HA-GB) resulted in the reduction of inflammation, the enhancement of re-epithelialization and angiogenesis, and the modulation of collagens from type III to type I, significantly promoting the healing outcome as compared with a commercially available wound dressing product (INTRASITE Gel). This study confirms a great therapeutic promise of HA-GB for the chronic wounds of diabetic patients.

Ginkgolide B Targets and Inhibits Creatine Kinase B to Regulate the CCT/TRiC-SK1 Axis and Exerts Pro-Angiogenic Activity in Middle Cerebral Artery Occlusion Mice

Promoting angiogenesis in the ischemic penumbra is a well-established method of ischemic stroke treatment. Ginkgolide B (GB) has long been recognized for its neuroprotective properties following stroke. As previously reported, it appears that stroke-induced neurogenesis and angiogenesis interact or are dependent on one another. Although the pharmacodynamic effect of GB on cerebral blood flow (CBF) following ischemic stroke has been reported, the molecular mechanism underlying this effect remains unknown. As such, this study sought to elucidate the pharmacodynamic effects and underlying mechanisms of GB on post-stroke angiogenesis. To begin, GB significantly increased the proliferation, migration, and tube formation capacity of mouse cerebral hemangioendothelioma cells (b.End3) and human umbilical vein endothelial cells (HUVEC). Additionally, GB significantly improved angiogenesis after oxygen-glucose deprivation/reperfusion (OGD/R) in endothelial cells. The dynamics of CBF, brain microvascular neovascularization and reconstruction, and brain endothelial tissue integrity were examined in middle cerebral artery occlusion (MCAO) mice following GB administration. Through label-free target detection techniques, we discovered for the first time that GB can specifically target Creatine Kinase B (CKB) and inhibit its enzymatic activity. Additionally, we demonstrated through network pharmacology and a series of molecular biology experiments that GB inhibited CKB and then promoted angiogenesis via the CCT/TRiC-SK1 axis. These findings shed new light on novel therapeutic strategies for neurological recovery and endothelial repair following ischemic stroke using GB therapy.

Microglia Polarization: A Novel Target of Exosome for Stroke Treatment

The vast majority of cells in the human body are capable of secreting exosomes. Exosomes have become an important vehicle for signaling between cells. Exosomes secreted by different cells have some of the structural and functional properties of that cell and thus have different regulatory functions. A large number of recent experimental studies have shown that exosomes from different sources have different regulatory effects on stroke, and the mechanisms still need to be elucidated. Microglia are core members of central intrinsic immune regulatory cells, which play an important regulatory role in the pathogenesis and progression of stroke. M1 microglia cause neuroinflammation and induce neurotoxic effects, while M2 microglia inhibit neuroinflammation and promote neurogenesis, thus exerting a series of neuroprotective effects. It was found that there is a close link between exosomes and microglia polarization, and that exosome inclusions such as microRNAs play a regulatory role in the M1/M2 polarization of microglia. This research reviews the role of exosomes in the regulation of microglia polarization and reveals their potential value in stroke treatment.

Promising Therapeutic Candidate for Myocardial Ischemia/Reperfusion Injury: What Are the Possible Mechanisms and Roles of Phytochemicals?

Percutaneous coronary intervention (PCI) is one of the most effective reperfusion strategies for acute myocardial infarction (AMI) despite myocardial ischemia/reperfusion (I/R) injury, causing one of the causes of most cardiomyocyte injuries and deaths. The pathological processes of myocardial I/R injury include apoptosis, autophagy, and irreversible cell death caused by calcium overload, oxidative stress, and inflammation. Eventually, myocardial I/R injury causes a spike of further cardiomyocyte injury that contributes to final infarct size (IS) and bound with hospitalization of heart failure as well as all-cause mortality within the following 12 months. Therefore, the addition of adjuvant intervention to improve myocardial salvage and cardiac function calls for further investigation. Phytochemicals are non-nutritive bioactive secondary compounds abundantly found in Chinese herbal medicine. Great effort has been put into phytochemicals because they are often in line with the expectations to improve myocardial I/R injury without compromising the clinical efficacy or to even produce synergy. We summarized the previous efforts, briefly outlined the mechanism of myocardial I/R injury, and focused on exploring the cardioprotective effects and potential mechanisms of all phytochemical types that have been investigated under myocardial I/R injury. Phytochemicals deserve to be utilized as promising therapeutic candidates for further development and research on combating myocardial I/R injury. Nevertheless, more studies are needed to provide a better understanding of the mechanism of myocardial I/R injury treatment using phytochemicals and possible side effects associated with this approach.

Baicalein ameliorates ischemic brain damage through suppressing proinflammatory microglia polarization via inhibiting the TLR4/NF-κB and STAT1 pathway

Microglial polarization mediated neuroinflammation plays an important role in the pathological process of stroke. The aim of this study is to determine whether baicalein indirectly ameliorates neuronal injury through modulating microglial polarization after stroke and if so, then by what mechanism. The effects of baicalein on microglial polarization were revealed through the middle cerebral artery occlusion mouse model (MCAO, n = 6), the lipopolysaccharide (LPS) + interferon-γ (IFN-γ) and oxygen-glucose deprivation (OGD) induced neuroinflammatory microglia model (BV2, n = 3), respectively. Mice were treated with baicalein (100 mg/kg, i.g.) after reperfusion, and followed by daily administrations for 3 days. Results showed that the infarct volumes at 3 d in vehicle and baicalein-treated MCAO mice were 91.18 ± 4.02% and 55.36 ± 4.10%. Baicalein improved sensorimotor functions (p < 0.01) after MCAO. Real-time PCR revealed that baicalein decreased proinflammatory markers expression (p < 0.05), while elevated the anti-inflammatory markers (p < 0.05) in vivo and in vitro. Both western blot and immunofluorescent staining further confirmed that baicalein reduced proinflammatory marker CD16 levels (p < 0.01) and enhanced anti-inflammatory marker CD206 or Arg-1 levels (p < 0.05). Notably, baicalein suppressed the release of proinflammatory cytokines (p < 0.05) and nitric oxide (NO, p < 0.001). Mechanistically, baicalein prevented increases in TLR4 protein levels (p < 0.001), the phosphorylation of IKBα and p65 (p < 0.01), and the nuclear translocation of NF-κB p65 (p < 0.05). The NF-κB inhibitor, BAY 11-7085, enhanced the inhibitory effect of baicalein on the proinflammatory microglial polarization. Baicalein also inhibited the phosphorylation of signal transducer and activator of transcription 1 (STAT1, p < 0.001). A microglia-neuron co-culture system revealed that baicalein driven neuroprotection against OGD induced neuronal damage through modulating microglial polarization (p < 0.05). Baicalein indirectly ameliorates neuronal injury after stroke by polarizing microglia toward the anti-inflammatory phenotype via inhibition of the TLR4/NF-κB pathway and down-regulation of phosphorylated STAT1, suggesting that baicalein might serve a potential therapy for stroke.

Anti-Inflammatory Mechanisms of Novel Synthetic Ruthenium Compounds

Inflammation is the primary biological reaction to induce severe infection or injury in the immune system. Control of different inflammatory cytokines, such as nitric oxide (NO), interleukins (IL), tumor necrosis factor alpha-(TNF-α), noncytokine mediator, prostaglandin E2 (PGE2), mitogen activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB), facilitates anti-inflammatory effect of different substances. Coordination metal complexes have been applied as metallo-drugs. Several metal complexes have found to possess potent biological activities, especially anticancer, cardioprotective, chondroprotective and anti-parasitosis activities. Among the metallo drugs, ruthenium-based (Ru) complexes have paid much attention in clinical applications. Despite the kinetic nature of Ru complexes is similar to platinum in terms of cell division events, their toxic effect is lower than that of cisplatin. This paper reviews the anti-inflammatory effect of novel synthetic Ru complexes with potential molecular mechanisms that are actively involved.

Modulating poststroke inflammatory mechanisms: Novel aspects of mesenchymal stem cells, extracellular vesicles and microglia

Inflammation plays an important role in the pathological process of ischemic stroke, and systemic inflammation affects patient prognosis. As resident immune cells in the brain, microglia are significantly involved in immune defense and tissue repair under various pathological conditions, including cerebral ischemia. Although the differentiation of M1 and M2 microglia is certainly oversimplified, changing the activation state of microglia appears to be an intriguing therapeutic strategy for cerebral ischemia. Recent evidence indicates that both mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (EVs) regulate inflammation and modify tissue repair under preclinical stroke conditions. However, the precise mechanisms of these signaling pathways, especially in the context of the mutual interaction between MSCs or MSC-derived EVs and resident microglia, have not been sufficiently unveiled. Hence, this review summarizes the state-of-the-art knowledge on MSC- and MSC-EV-mediated regulation of microglial activity under ischemic stroke conditions with respect to various signaling pathways, including cytokines, neurotrophic factors, transcription factors, and microRNAs.

Ginkgolide B Alleviates Learning and Memory Impairment in Rats With Vascular Dementia by Reducing Neuroinflammation via Regulating NF-κB Pathway

Ginkgobalide B (GB) as the main active ingredient of traditional Chinese medicine Ginkgo biloba extract is reported to reduce neuroinflammation, protect neurons and promote cognitive learning ability. To explore that GB can reduce neuroinflammation through regulating nuclear factor-kappaB (NF-κB) signaling pathway and overcome cognitive dysfunction in rats with vascular dementia (VD), we aim at investigating the potential effect of GB on enhancing cognitive function in rats with VD. It was found that GB improved survival of oxygen-glucose deprivation (OGD) treated SH-SY5Y cells by attenuating inflammatory response via Toll-like Receptor 4 (TLR4)/NF-κB pathway. When rats were treated with bilateral common carotid artery occlusion (BCCAO) for 24 h, saline and GB were administered in Sprague-Dawley (SD) rats via a single intraperitoneal injection for consecutive 14 days. The behavioral changes of VD like rats treated with GB were observed through open field test, Morris water maze (MWM) and Y-maze electric maze. Nissl staining and immunofluorescence were used to observe changes of neurons in the hippocampus of rats. Western blot analysis was performed by detecting NF-κB pathway related inflammatory factors. The results found that GB can significantly improve the learning and memory ability of VD rats by reducing TLR4/NF-κB mediated neuroinflammation. In conclusion, GB seemed to be a potential drug for amelioration of learning and memory impairment in rats with VD.

Quercetin hinders microglial activation to alleviate neurotoxicity via the interplay between NLRP3 inflammasome and mitophagy

Activated microglia are an important type of innate immune cell in the brain, and they secrete inflammatory cytokines into the extracellular milieu, exert neurotoxicity to surrounding neurons and are involved in the pathogenesis of many brain disorders. Quercetin (Qu), a natural flavonoid, is known to have anti-inflammatory and antioxidant properties. Previous studies have shown that both increased reactive oxygen species (ROS) stress and decreased autophagy participate in the activation of microglial. In the current study, we showed that Qu significantly attenuated LPS-induced inflammatory factor production, cell proliferation and NF-κB activation of microglia. Importantly, Qu decreased the levels of NLR family, pyrin domain containing three (NLRP3) inflammasome and pyroptosis-related proteins, including NLRP3, active caspase-1, GSDMD N-terminus and cleaved IL-1β. Further study indicated that this anti-inflammatory effect of Qu was associated with mitophagy regulation. Importantly, Qu promoted mitophagy to enhance damaged mitochondrial elimination, which then reduced mtROS accumulation and alleviated NLRP3 inflammasome activation. Then, we confirmed that Qu treatment protected primary neurons against LPS-induced microglial toxicity and alleviated neurodegeneration in both depression and PD mouse models. Further IL-1β administration blunted these neuroprotective effects of Qu in vitro and in vivo. This work illustrated that Qu prevents neuronal injury via inhibition of mtROS-mediated NLRP3 inflammasome activation in microglia through promoting mitophagy, which provides a potential novel therapeutic strategy for neuroinflammation-related diseases.

Ginkgolide B monotherapy reverses osteoporosis by regulating oxidative stress-mediated bone homeostasis

Osteoporosis is characterized by reductions in bone mass, which could be attributed to the dysregulation of bone homeostasis, such as the loss of balance between bone-resorbing osteoclasts and bone-forming osteoblasts. Elevated levels of oxidative stress increase bone resorption by promoting osteoclastogenesis and inhibiting the osteogenesis. Ginkgolide B (GB), a small natural molecule from Ginkgo biloba, has been reported to possess pharmacological activities by regulating reactive oxygen species (ROS) in aging-related degenerative diseases. Herein, we assessed the therapeutic effects of GB on the bone phenotypes of mice with osteoporosis induced by (I) aging, (II) ovariectomy, and (III) glucocorticoids. In all three animal models, oral gavage of GB significantly improved bone mass consistent with the increase in the OPG-to-RANKL ratio. In the in vitro experiments, GB promoted osteogenesis in aged mesenchymal stem cells (MSCs) and repressed osteoclastogenesis in aged macrophages by reducing ROS. The serum protein profile in GB-treated aged mice revealed moderate rejuvenating effects; signaling pathways associated with ROS were also regulated. The anabolic and anti-catabolic effects of GB were illustrated by the reduction in ROS. Our results indicate that GB is effective in treating osteoporosis. The use of GB in patients with osteoporosis is worthy of further clinical investigation.

Lipocalin 2 regulates iron homeostasis, neuroinflammation, and insulin resistance in the brains of patients with dementia: Evidence from the current literature

Dementia accompanied by memory loss is considered one of the most common neurodegenerative diseases worldwide, and its prevalence is gradually increasing. Known risk factors for dementia include genetic background, certain lifestyle and dietary patterns, smoking, iron overload, insulin resistance, and impaired glucose metabolism in the brain. Here, we review recent evidence on the regulatory role of lipocalin 2 (LCN2) in dementia from various perspectives. LCN2 is a neutrophil gelatinase-associated protein that influences diverse cellular processes, including the immune system, iron homeostasis, lipid metabolism, and inflammatory responses. Although its functions within the peripheral system are most widely recognized, recent findings have revealed links between LCN2 and central nervous system diseases, as well as novel roles for LCN2 in neurons and glia. Furthermore, LCN2 may modulate diverse pathological mechanisms involved in dementia. Taken together, LCN2 is a promising therapeutic target with which to address the neuropathology of dementia.

Ginkwanghols A and B, osteogenic coumaric acid-aliphatic alcohol hybrids from the leaves of Ginkgo biloba

Ginkgo biloba (Ginkgoaceae), commonly known as "ginkgo", is called a living fossil, and it has been cultivated early in human history for various uses in traditional medicine and as a source of food. As part of ongoing research to explore the chemical diversity and biologically active compounds from natural resources, two new coumaric acid-aliphatic alcohol hybrids, ginkwanghols A (1) and B (2) were isolated from the leaves of G. biloba. The coumaric acid-aliphatic alcohol hybrids of natural products have rarely been reported. The structures of the new compounds were determined by extensive NMR spectroscopic analysis, HRESI-MS, and quantum chemical ECD calculations, and by comparing the experimental HRESI-MS/MS spectrum of chemically transformed compound 1a with the predicted HRESI-MS/MS spectra proposed from CFM-ID 3.0, a software tool for MS/MS spectral prediction and MS-based compound identification. Ginkwanghols A (1) and B (2) increased alkaline phosphatase (ALP) production in C3H10T1/2, a mouse mesenchymal stem cell line, in a dose-dependent manner. In addition, ginkwanghols A and B mediated the promotion of osteogenic differentiation as indicated by the induction of the mRNA expression of the osteogenic markers ALP and osteopontin (OPN).

[The role of the inflammatory process in the development of post-stroke cognitive impairment]

Post-stroke cognitive impairment (PCI) is a common complication of stroke. PCI in most cases is associated with an increased risk of progression to dementia, with a progression rate of 8-15% per year. When post-stroke cognitive impairment reaches dementia, patients lose independence, professional and social maladjustment occurs, which, in turn, significantly worsen the quality of life and reduce the rehabilitation potential. According to many experimental and clinical studies, the inflammatory process has an important role in the development of PCI. Several previous studies have looked at the association between inflammatory markers and PCI, with some results conflicting with specific biomarkers. Based on the results of studies, inflammatory markers such as IL-8, IL-12 and ESR were closely associated with PCI, high ESR values are associated with worse cognitive impairment, especially memory. The relationship was not confirmed between the markers IFN-gamma, TNF-α and PCI. With regard to IL-1β, IL-6, IL-10, CRP, the results obtained are not unambiguous. Thus, the inflammatory process in the development of PCI has an important role, including a series of complex reactions, the combined effect of which induces neuronal damage and loss of synapses that ultimately leads to cognitive impairment.

Neuroprotective Phytochemicals in Experimental Ischemic Stroke: Mechanisms and Potential Clinical Applications

Ischemic stroke is a challenging disease with high mortality and disability rates, causing a great economic and social burden worldwide. During ischemic stroke, ionic imbalance and excitotoxicity, oxidative stress, and inflammation are developed in a relatively certain order, which then activate the cell death pathways directly or indirectly via the promotion of organelle dysfunction. Neuroprotection, a therapy that is aimed at inhibiting this damaging cascade, is therefore an important therapeutic strategy for ischemic stroke. Notably, phytochemicals showed great neuroprotective potential in preclinical research via various strategies including modulation of calcium levels and antiexcitotoxicity, antioxidation, anti-inflammation and BBB protection, mitochondrial protection and antiapoptosis, autophagy/mitophagy regulation, and regulation of neurotrophin release. In this review, we summarize the research works that report the neuroprotective activity of phytochemicals in the past 10 years and discuss the neuroprotective mechanisms and potential clinical applications of 148 phytochemicals that belong to the categories of flavonoids, stilbenoids, other phenols, terpenoids, and alkaloids. Among them, scutellarin, pinocembrin, puerarin, hydroxysafflor yellow A, salvianolic acids, rosmarinic acid, borneol, bilobalide, ginkgolides, ginsenoside Rd, and vinpocetine show great potential in clinical ischemic stroke treatment. This review will serve as a powerful reference for the screening of phytochemicals with potential clinical applications in ischemic stroke or the synthesis of new neuroprotective agents that take phytochemicals as leading compounds.

Minocycline promotes functional recovery in ischemic stroke by modulating microglia polarization through STAT1/STAT6 pathways

BACKGROUND

Increasing evidence suggests that microglia experience two distinct phenotypes after acute ischemic stroke (AIS): a deleterious M1 phenotype and a neuroprotective M2 phenotype. Promoting the phenotype shift of M1 microglia to M2 microglia is thought to improve functional recovery after AIS. Minocycline, a tetracycline antibiotic, can improve functional recovery after cerebral ischemia in pre-clinical and clinical research. However, the role and mechanisms of minocycline in microglia polarization is unclear.

METHODS

Using the transient middle cerebral artery occlusion - reperfusion (MCAO/R) model, we treated mice with saline or different minocycline concentration (10, 25, or 50 mg/kg, i.p., daily for 2 wk) at 24 h after reperfusion. Neurobehavioral evaluation, rotarod test, and corner turning test were carried out on day 14 after reperfusion. Then, neuronal injury, reactive gliosis, and microglia polarization were performed on day 7 following MCAO/R. Finally, we treated primary microglial cultures with LPS (Lipopolysaccharide; 100 ng/mL) plus IFN-γ (20 ng/mL) 24 h to induce M1 phenotype and observed the effects of minocycline on the M1/M2-related mRNAs and the STAT1/STAT6 pathway.

RESULTS

We found that a 14-day treatment with minocycline increased the survival rate and promoted functional outcomes evaluated with neurobehavioral evaluation, rotarod test, and corner turning test. Meanwhile, minocycline reduced the brain infarct volume, alleviated neuronal injury, and suppressed reactive gliosis on day 7 following MCAO/R. Moreover, we observed an additive effect of minocycline on microglia polarization to the M1 and M2 phenotypes in vivo and in vitro. In the primary microglia, we further found that minocycline prevented neurons from OGD/R-induced cell death in neuron-microglia co-cultures via regulating M1/M2 microglia polarization through the STAT1/STAT6 pathway.

CONCLUSION

Minocycline promoted microglial M2 polarization and inhibited M1 polarization, leading to neuronal survival and neurological functional recovery. The findings deepen our understanding of the mechanisms underlying minocycline-mediated neuroprotection in AIS.

Combination of curcumin and ginkgolide B inhibits cystogenesis by regulating multiple signaling pathways

Autosomal dominant polycystic kidney disease (ADPKD), a common disease with a high incidence ratio of between 1/400 and 1/1,000 individuals, often results in kidney failure and even mortality. However, there are relatively few effective treatments available, and treatment is limited to lifelong hemodialysis or kidney transplant. Our previous studies have reported that curcumin (Cur) and ginkgolide B (GB) inhibited cystogenesis by regulating the Ras/ERK MAPK signaling pathway. In the present study, it was hypothesized that Cur and GB may have a synergistic effect on the inhibition of cystogenesis, and their synergistic effect may be the result of regulation of multiple signaling pathways. To assess this hypothesis, an in vitro Madin‑Darby canine kidney (MDCK) cyst model and an in vivo kidney‑specific polycystin 1 transient receptor potential channel interacting (Pkd1) knockout mouse model were established to observe the effects of the combination of Cur and GB. The cysts exposed to Cur, GB and Cur combined with GB became small thick‑walled cysts, small thin‑walled cysts and round shaped cell colonies, respectively. The combination of Cur and GB was more effective compared with either treatment alone in inhibiting cystogenesis. Additionally, to the best of our knowledge, the present study was the first to demonstrate the synergistic effect of Cur and GB on the inhibition of cystogenesis in Pkd1 knockout mice. Cur may have mediated its anti‑cyst effects by blocking EGFR/ERK1/2, JNK and PI3K/mTOR signaling pathways, while GB may have inhibited cystogenesis via the downregulation of the EGFR/ERK1/2, JNK and p38 signaling pathways. These results provide a proof‑of‑concept for application of the combination of Cur and GB in inhibiting cystogenesis in ADPKD.

Sirt1 activator SRT2104 protects against oxygen-glucose deprivation/reoxygenation-induced injury via regulating microglia polarization by modulating Sirt1/NF-κB pathway

Cerebral ischemic/reperfusion injury is the most common neurological disorder and the second leading cause of death worldwide. Modulating microglia polarization from pro-inflammatory M1 phenotype to anti-inflammatory M2 state has been suggested as a potential therapeutic approach in the treatment of this injury. SRT2104, a novel activator of histone deacetylase Sirtuin-1 (Sirt1), has recently been shown to have anti-inflammation properties. However, the effect of SRT2104 on cerebral ischemic/reperfusion injury has not been elucidated. Here, we found that SRT2104 inhibited neuron and microglia death directly and indirectly through microglia condition medium from an oxygen glucose deprivation/reoxygenation (OGD/R) -induced cell injury models. Moreover, SRT2104 treatment modulated the microglia polarization shift from the M1 phenotype and skewed toward the M2 phenotype. Additionally, we found that SRT2104 could significant inhibit the activation of NF-κB and enhanced Sirt1 expression in microglia. Mechanism studies using the BV2 microglial cell line confirmed that knockdown Sirt1 significantly reduced the effect of SRT2104 on the activation of NF-κB pathway and microglial phenotype shift. Altogether, our result shows SRT2104 protect OGD/R-induced injury through shifting microglia phenotype, which may have potential in further studies as a novel neuroprotective agent for cerebral ischemic/reperfusion injury therapy.

Ginkgolide B Maintains Calcium Homeostasis in Hypoxic Hippocampal Neurons by Inhibiting Calcium Influx and Intracellular Calcium Release

Ginkgolide B (GB), a terpene lactone and active ingredient of Ginkgo biloba, shows protective effects in neuronal cells subjected to hypoxia. We investigated whether GB might protect neurons from hypoxic injury through regulation of neuronal Ca²⁺ homeostasis. Primary hippocampal neurons subjected to chemical hypoxia (0.7 mM CoCl₂) in vitro exhibited an increase in cytoplasmic Ca²⁺ (measured from the fluorescence of fluo-4), but this effect was significantly diminished by pre-treatment with 0.4 mM GB. Electrophysiological recordings from the brain slices of rats exposed to hypoxia in vivo revealed increases in spontaneous discharge frequency, action potential frequency and calcium current magnitude, and all these effects of hypoxia were suppressed by pre-treatment with 12 mg/kg GB. Western blot analysis demonstrated that hypoxia was associated with enhanced mRNA and protein expressions of Ca_v1.2 (a voltage-gated Ca²⁺ channel), STIM1 (a regulator of store-operated Ca²⁺ entry) and RyR2 (isoforms of Ryanodine Receptor which mediates sarcoplasmic reticulum Ca²⁺ release), and these actions of hypoxia were suppressed by GB. Taken together, our in vitro and in vivo data suggest that GB might protect neurons from hypoxia, in part, by regulating Ca²⁺ influx and intracellular Ca²⁺ release to maintain Ca²⁺ homeostasis.

Attenuation of acute and chronic inflammation using compounds derived from plants

The appearance of excessive inflammatory activity is associated with onset of many disease states. Such non-productive responses are often the basis of the mortality consequent to incurring numerous disorders. The current outbreak of coronavirus disease 2019 caused by the virus "severe acute respiratory syndrome coronavirus 2" is a striking reflection of the inadequacy of current medical science to adequately address this issue. The usefulness of a range of materials of botanical origin in the attenuation of both chronic and acute inflammatory responses to various disease stressors is described. The properties of preparations of plant-based origin often parallel those of synthesized pharmacologics, but differ from them in some key respects. These differences can lead to more traditional preparations having distinct therapeutic advantages but also a number of specific shortcomings. The strengths and weaknesses of these materials are objectively contrasted with that of a more orthodox pharmacological approach. Each of these emphases in style has specific advantages and they should not be considered as competitors, but rather as accomplices in combating adverse states involving derangement of immune function.

Therapeutic potential of nutraceuticals to protect brain after stroke

Stroke leads to significant neuronal death and long-term neurological disability due to synergistic pathogenic mechanisms. Stroke induces a change in eating habits and in many cases, leads to undernutrition that aggravates the post-stroke pathology. Proper nutritional regimen remains a major strategy to control the modifiable risk factors for cardiovascular and cerebrovascular diseases including stroke. Studies indicate that nutraceuticals (isolated and concentrated form of high-potency natural bioactive substances present in dietary nutritional components) can act as prophylactic as well as adjuvant therapeutic agents to prevent stroke risk, to promote ischemic tolerance and to reduce post-stroke consequences. Nutraceuticals are also thought to regulate blood pressure, delay neurodegeneration and improve overall vascular health. Nutraceuticals potentially mediate these effects by their powerful antioxidant and anti-inflammatory properties. This review discusses the studies that have highlighted the translational potential of nutraceuticals as stroke therapies.

Emerging neuroprotective strategies for the treatment of ischemic stroke: An overview of clinical and preclinical studies

Stroke is the leading cause of disability and thesecond leading cause of death worldwide. With the global population aged 65 and over growing faster than all other age groups, the incidence of stroke is also increasing. In addition, there is a shift in the overall stroke burden towards younger age groups, particularly in low and middle-income countries. Stroke in most cases is caused due to an abrupt blockage of an artery (ischemic stroke), but in some instances stroke may be caused due to bleeding into brain tissue when a blood vessel ruptures (hemorrhagic stroke). Although treatment options for stroke are still limited, with the advancement in recanalization therapy using both pharmacological and mechanical thrombolysis some progress has been made in helping patients recover from ischemic stroke. However, there is still a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke to protect the brain from damage prior to and during recanalization, extend the therapeutic time window for intervention and further improve functional outcome. The current review has assessed the past challenges in developing neuroprotective strategies, evaluated the recent advances in clinical trials, discussed the recent initiative by the National Institute of Neurological Disorders and Stroke in USA for the search of novel neuroprotectants (Stroke Preclinical Assessment Network, SPAN) and identified emerging neuroprotectants being currently evaluated in preclinical studies. The underlying molecular mechanism of each of the neuroprotective strategies have also been summarized, which could assist in the development of future strategies for combinational therapy in stroke treatment.

Role of Ginkgolides in the Inflammatory Immune Response of Neurological Diseases: A Review of Current Literatures

The inflammatory immune response (IIR) is a physiological or excessive systemic response, induced by inflammatory immune cells according to changes in the internal and external environments. An excessive IIR is the pathological basis for the generation and development of neurological diseases. Ginkgolides are one of the important medicinal ingredients in Ginkgo biloba. Many studies have verified that ginkgolides have anti-platelet-activating, anti-apoptotic, anti-oxidative, neurotrophic, and neuroimmunomodulatory effects. Inflammatory immunomodulation is mediated by inhibition of the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways. They also inhibit the platelet-activating factor (PAF)-mediated signal transduction to attenuate the inflammatory response. Herein, we reviewed the studies on the roles of ginkgolides in inflammatory immunomodulation and suggested its potential role in novel treatments for neurological diseases.

Targeting Wnt/β-Catenin Pathway for Developing Therapies for Hair Loss

Persistent hair loss is a major cause of psychological distress and compromised quality of life in millions of people worldwide. Remarkable progress has been made in understanding the molecular basis of hair loss and identifying valid intracellular targets for designing effective therapies for hair loss treatment. Whereas a variety of growth factors and signaling pathways have been implicated in hair cycling process, the activation of Wnt/β-catenin signaling plays a central role in hair follicle regeneration. Several plant-derived chemicals have been reported to promote hair growth by activating Wnt/β-catenin signaling in various in vitro and in vivo studies. This mini-review sheds light on the role of Wnt/β-catenin in promoting hair growth and the current progress in designing hair loss therapies by targeting this signaling pathway.

Ginkgolide B attenuates myocardial infarction-induced depression-like behaviors via repressing IL-1β in central nervous system

Depression is common in patients with myocardial infarction (MI), attributing to worse outcomes. Inflammatory response in the central nervous system (CNS) is considered to be a potential mechanism underlying MI induced depression. Our former research demonstrated Ginkgo biloba extract played an important role in the repression of hippocampus inflammation in heart failure mice with depressive behaviors. This study was designed to investigate the effect of Ginkgolide B (GB) on MI-induced depression-like behaviors in post MI mice. After MI surgery induced by coronary ligation, MI mice behaved depressingly, detected by open field test (OFT) and the sucrose preference test (SPT), which was reserved by GB treatment. Meanwhile, the reduction of 5-HT and increase of interleukin 1 beta (IL-1β) in median raphe nucleus and cortex indicated potential mechanisms underlying MI-induced depression-like behaviors, which were significantly reserved by GB treatment. Moreover, the consistent variation of IL-1β and phospho-STAT3 expression in brain tissues, indicated a role of STAT3 pathway in IL-1β production and anti-inflammatory effect of GB. In conclusion, GB has great benefits in effective treatment for depression post MI through reducing the levels of proinflammatory cytokines via STAT3 pathway, implicating potential effects in improving depression status in patients with MI.

Modulators of microglia activation and polarization in ischemic stroke (Review)

Ischemic stroke is one of the leading causes of mortality and disability worldwide. However, there is a current lack of effective therapies available. As the resident macrophages of the brain, microglia can monitor the microenvironment and initiate immune responses. In response to various brain injuries, such as ischemic stroke, microglia are activated and polarized into the proinflammatory M1 phenotype or the anti‑inflammatory M2 phenotype. The immunomodulatory molecules, such as cytokines and chemokines, generated by these microglia are closely associated with secondary brain damage or repair, respectively, following ischemic stroke. It has been shown that M1 microglia promote secondary brain damage, whilst M2 microglia facilitate recovery following stroke. In addition, autophagy is also reportedly involved in the pathology of ischemic stroke through regulating the activation and function of microglia. Therefore, this review aimed to provide a comprehensive overview of microglia activation, their functions and changes, and the modulators of these processes, including transcription factors, membrane receptors, ion channel proteins and genes, in ischemic stroke. The effects of autophagy on microglia polarization in ischemic stroke were also reviewed. Finally, future research areas of ischemic stroke and the implications of the current knowledge for the development of novel therapeutics for ischemic stroke were identified.

Ginkgolide B inhibits hydrogen peroxide‑induced apoptosis and attenuates cytotoxicity via activating the PI3K/Akt/mTOR signaling pathway in H9c2 cells

Ginkgolide B (GB) is a diterpene lactone found in the leaves of the traditional Chinese medicinal plant Ginkgo that has been shown to have various pharmacological effects. However, the anti-apoptotic properties of GB in cardiovascular disease remain poorly understood. The present study aimed to investigate the effect of GB on hydrogen peroxide-induced cell injury in cardiac H9c2 cells, and to further clarify its protective mechanism of action. An in vitro hydrogen peroxide-treated H9c2 cell model was used in order to mimic myocardial ischemia-reperfusion (I/R) injury. Cell viability was assessed by the Cell Counting Kit-8 assay. The induction of apoptosis was determined by flow cytometry and staining was performed using Hoechst 33342. In addition, the effect of GB on the expression levels of apoptosis-associated proteins was evaluated by western blot analysis. The present study demonstrated that GB protected against hydrogen peroxide-induced cytotoxicity and cell apoptosis in H9c2 cardiac cells. GB upregulated the expression level of the anti-apoptotic protein Bcl-2 and downregulated the expression levels of the pro-apoptotic proteins cleaved caspase-3 and Bax in hydrogen peroxide-treated H9c2 cells. The molecular mechanism underlying the anti-apoptotic effects of GB was subsequently detected. GB pretreatment activated the PI3K/Akt/mTOR signaling pathway and caused an increase in the phosphorylation levels of Akt and mTOR in hydrogen peroxide-treated H9c2 cells. These results revealed that GB inhibited hydrogen peroxide-induced apoptosis in H9c2 cells via activation of the PI3K/Akt/mTOR signaling pathway. These findings indicate the potential therapeutic benefits of GB in the treatment of myocardial I/R injury.

Heterogeneity of Microglia Phenotypes: Developmental, Functional and Some Therapeutic Considerations

BACKGROUND

Microglia play a pivotal role in maintaining homeostasis in complex brain environment. They first exist as amoeboid microglial cells (AMCs) in the developing brain, but with brain maturation, they transform into ramified microglial cells (RMCs). In pathological conditions, microglia are activated and have been classified into M1 and M2 phenotypes. The roles of AMCs, RMCs and M1/M2 microglia phenotypes especially in pathological conditions have been the focus of many recent studies.

METHODS

Here, we review the early development of the AMCs and RMCs and discuss their specific functions with reference to their anatomic locations, immunochemical coding etc. M1 and M2 microglia phenotypes in different neuropathological conditions are also reviewed.

RESULTS

Activated microglia are engaged in phagocytosis, production of proinflammatory mediators, trophic factors and synaptogenesis etc. Prolonged microglia activation, however, can cause damage to neurons and oligodendrocytes. The M1 and M2 phenotypes featured prominently in pathological conditions are discussed in depth. Experimental evidence suggests that microglia phenotype is being modulated by multiple factors including external and internal stimuli, local demands, epigenetic regulation, and herbal compounds.

CONCLUSION

Prevailing views converge that M2 polarization is neuroprotective. Thus, proper therapeutic designs including the use of anti-inflammatory drugs, herbal agents may be beneficial in suppression of microglial activation, especially M1 phenotype, for amelioration of neuroinflammation in different neuropathological conditions. Finally, recent development of radioligands targeting 18 kDa translocator protein (TSPO) in activated microglia may hold great promises clinically for early detection of brain lesion with the positron emission tomography.

Synthetic Ruthenium Complex TQ-6 Potently Recovers Cerebral Ischemic Stroke: Attenuation of Microglia and Platelet Activation

Activated microglia are crucial in the regulation of neuronal homeostasis and neuroinflammation. They also contribute to neuropathological processes after ischemic stroke. Thus, finding new approaches for reducing neuroinflammation has gained considerable attention. The metal ruthenium has gained notable attention because of its ability to form new complexes that can be used in disease treatment. [Ru(η6-cymene)2-(1H-benzoimidazol-2-yl)-quinoline Cl]BF4 (TQ-6), a potent ruthenium (II)-derived compound, was used in this study to investigate its neuroprotective action against microglia activation, middle cerebral artery occlusion (MCAO)-induced embolic stroke, and platelet activation, respectively. TQ-6 (2 μM) potently diminished inflammatory mediators (nitric oxide/inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2)) expression, nuclear factor kappa B (NF-κB) p65 phosphorylation, nuclear translocation, and hydroxyl radical (OH^•) formation in LPS-stimulated microglia. Conversely, TQ-6 increased the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Moreover, it significantly reduced brain infarct volume and edema in MCAO mice. Additionally, it drastically inhibited platelet aggregation and OH^• production in mice platelets. This study confirmed that TQ-6 exerts an anti-neuroinflammatory effect on microglia activation through neuroprotection, antiplatelet activation, and free radical scavenging. The authors propose that TQ-6 might mitigate neurodegenerative pathology by inhibiting the NF-κB-mediated downstream pathway (iNOS and COX-2) and enhancing Nrf2/HO-1 signaling molecules in microglia.

Ginkgo diterpene lactones inhibit cerebral ischemia/reperfusion induced inflammatory response in astrocytes via TLR4/NF-κB pathway in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. (Ginkgoaceae) is a traditional Chinese medicine known to treating stroke and other cardio-cerebrovascular diseases for thousands of years in China. Ginkgo diterpene lactones (GDL) attracted much attention because of their neuroprotective properties.

AIM OF THE STUDY

To uncover the effects of GDL, which consist of ginkgolide A (GA), ginkgolide B (GB), and ginkgolide K (GK), on ischemic stroke, as well as the underlying molecular mechanisms.

MATERIALS AND METHODS

We used middle cerebral artery occlusion/reperfusion (MCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R) models mimicking the process of ischemia/reperfusion in vivo and in vitro, respectively. Anticoagulant effects of GDL were investigated on platelet activating factor (PAF), arachidonic acid (AA) and adenosine diphosphate (ADP)-induced platelet aggregation both in vivo and in vitro. We also evaluated the effects of GDL on lipopolysaccharide (LPS)-induced inflammatory response in primary cultured rats' astrocytes. Infarct size, neurological deficit score, and brain edema were measured at 72 h after MCAO. Immunohistochemistry was utilized to analyze neurons necrosis and astrocytes activation. Expression of pro-inflammatory cytokines, including tumor necrotic factor-α (TNF-α) and interleukin-1β (IL-1β) were detected using enzyme-linked immunosorbent assay (ELISA) and real time PCR. The levels of toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) were assessed by real time PCR or Western blot.

RESULTS

Compared with MCAO/R rats, GDL significantly reduced infarct size and brain edema, improved neurological deficit score. Meanwhile, GDL suppressed platelet aggregation, astrocytes activation, pro-inflammatory cytokines releasing, TLR4 mRNA expression and transfer of NF-κB from cytoplasm to nucleus. Furthermore, GDL alleviated OGD/R injury and LPS-induced inflammatory response in primary astrocytes, characterized by promoting cell viability, decreasing lactate dehydrogenase (LDH) activity, and inhibiting IL-1β and TNF-α releasing.

CONCLUSIONS

In summary, GDL attenuate cerebral ischemic injury, inhibit platelet aggregation and astrocytes activation. The anti-inflammatory activity might be associated with the downregulation of TLR4/NF-κB signal pathway. Our present findings provide an innovative insight into the novel treatment of GDL in ischemic stroke therapy.