The Improving Effect of HL271, a Chemical Derivative of Metformin, a Popular Drug for Type II Diabetes Mellitus, on Aging-induced Cognitive Decline

Extensive therapeutic effects, underlying molecular mechanisms and disease treatment prediction of Metformin: a systematic review

Metformin (Met), a first-line management for type 2 diabetes mellitus, has been expansively employed and studied with results indicating its therapeutic potential extending beyond glycemic control. Beyond its established role, this therapeutic drug demonstrates a broad spectrum of action encompassing over 60 disorders, encompassing metabolic conditions, inflammatory disorders, carcinomas, cardiovascular diseases, and cerebrovascular pathologies. There is clear evidence of Met's action targeting specific nodes in the molecular pathways of these diseases and, intriguingly, interactions with the intestinal microbiota and epigenetic processes have been explored. Furthermore, novel Met derivatives with structural modifications tailored to diverse diseases have been synthesized and assessed. This manuscript proffers a comprehensive thematic review of the diseases amenable to Met treatment, elucidates their molecular mechanisms, and employs informatics technology to prospect future therapeutic applications of Met. These data and insights gleaned considerably contribute to enriching our understanding and appreciation of Met's far-reaching clinical potential and therapeutic applicability.

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.

Inhibiting mitochondrial inflammation through Drp1/HK1/NLRP3 pathway: A mechanism of alpinetin attenuated aging-associated cognitive impairment

Mitochondrial inflammation triggered by abnormal mitochondrial division and regulated by the Drp1/HK1/NLRP3 pathway is correlated with the progression of aging-associated cognitive impairment (AACI). Alpinetin is a novel flavonoid derived from Zingiberaceae that has many bioactivities such as antiinflammation and anti-oxidation. However, whether alpinetin alleviates AACI by suppressing Drp1/HK1/NLRP3 pathway-inhibited mitochondrial inflammation is still unknown. In the present study, D-galactose (D-gal)-induced aging mice and BV-2 cells were used, and the effects of alpinetin on learning and memory function, neuroprotection and activation of the Drp1/HK1/NLRP3 pathway were investigated. Our data indicated that alpinetin significantly alleviated cognitive dysfunction and neuronal damage in the CA1 and CA3 regions of D-gal-treated mice. Moreover, D-gal-induced microglial activation was markedly reduced by alpinetin by inhibiting the Drp1/HK1/NLRP3 pathway-suppressed mitochondrial inflammation, down-regulating the levels of p-Drp1 (s616), VDAC, NLRP3, ASC, Cleaved-caspase 1, IL-18, and IL-1β, and up-regulating the expression of HK1. Furthermore, after Drp1 inhibition by Mdivi-1 in vitro, the inhibitory effect of alpinetin on Drp1/HK1/NLRP3 pathway was more evident. In summary, the current results implied that alpinetin attenuated aging-related cognitive deficits by inhibiting the Drp1/HK1/NLRP3 pathway and suppressing mitochondrial inflammation, suggesting that the inhibition of the Drp1/HK1/NLRP3 pathway is one of the mechanisms by which alpinetin attenuates AACI.

Treat more than heat-New therapeutic implications of Cimicifuga racemosa through AMPK-dependent metabolic effects

BACKGROUND

Cimicifuga racemosa extracts (CRE) have obtained a "well-established use status" in the treatment of postmenopausal (i.e., climacteric) complaints, which predominantly include vasomotor symptoms such as hot flushes and sweating, as well as nervousness, irritability, and metabolic changes. Although characteristic postmenopausal complaints are known for a very long time and the beneficial effects of CRE on climacteric symptoms are well accepted, both the pathophysiology of postmenopausal symptoms and the mechanism of action of CREs are not yet fully understood. In particular, current hypotheses suggest that changes in the α-adrenergic and serotonergic signaling pathways secondary to estrogen depletion are responsible for the development of hot flushes.

PURPOSE

Some of the symptoms associated with menopause cannot be explained by these hypotheses. Therefore, we attempted to extend our classic understanding of menopause by integrating of partly age-related metabolic impairments.

METHODS

A comprehensive literature survey was performed using the PubMed database for articles published through September 2021. The following search terms were used: (cimicifuga OR AMPK) AND (hot flush* OR hot flash* OR menopaus* OR osteoporos* OR cancer OR antioxida* OR cardiovasc*). No limits were set with respect to language, and the references cited in the articles retrieved were used to identify additional publications.

RESULTS

We found that menopause is a manifestation of the general aging process, with specific metabolic changes that aggravate menopausal symptoms, which are accelerated by estrogen depletion and associated neurotransmitter dysregulation. Cimicifuga extracts with their metabolic effects mitigate climacteric symptoms but may also modulate the aging process itself. Central to these effects are effects of CRE on the metabolic key regulator, the AMP-activated protein kinase (AMPK).

CONCLUSIONS

As an extension of this effect dimension, other off-label indications may appear attractive in the sense of repurposing of this herbal treatment.

Evaluation of nootropic activity of telmisartan and metformin on diazepam-induced cognitive dysfunction in mice through AMPK pathway and amelioration of hippocampal morphological alterations

Cognitive impairments such as dementia are considered the biggest challenges for public health. Benzodiazepines are often prescribed for treatment of anxiety disorder but they are associated with elevated risk of dementia. The present study has been designed to evaluate the neuroprotective effect of telmisartan and metformin on diazepam-induced cognitive dysfunction in mice. Piracetam was used as an established nootropic agent. Mice were divided into 8 groups, group1; control group which received normal saline. groups 2, 3 and 4 were received telmisartan 0.3 mg/kg/day, metformin 100 mg/kg/day and piracetam 200 mg/kg/day respectively. group 5; DZP group that injected with diazepam 2.5 mg/kg, groups 6, 7 and 8 were received diazepam 2.5 mg/kg + telmisartan 0.3 mg/kg/day, metformin 100 mg/kg/day and piracetam 200 mg/kg/day respectively. All drugs were administrated for 15 successive days. Cognitive skills of the animals were examined with Elevated plus maze and Passive Shock Avoidance tests. Investigations of oxidative stress markers were performed. Gene expression levels of TNF-α, NFκB, Caspase 3 and AMPK were analyzed using RT-PCR. Histological and immunohistochemical techniques were performed in hippocampus using H&E, cresyl violet stain, anti GFAP and anti COX-2 immunostain. The study revealed that administration of diazepam increased initial and retention transfer latency as well as it decreased step down latency that means it caused memory impairment. There was a significant increase in hippocampal expression levels of TNF-α, NFκB, and Caspase 3 and downregulation of AMPK expression levels associated with increased neurodegeneration, astrocytes activation and COX-2 immunohistochemical staining. This study indicates that diazepam caused a decline in cognitive function depending on hippocampal activity. Telmisartan, a common antihypertensive agent and metformin, a traditional antidiabetic drug improved this cognitive dysfunction through their anti-oxidant and anti-inflammatory effect as they decreased initial and retention transfer latency as well as it increased step down latency. Also they decreased TNF-α, NFκB, and Caspase 3 and upregulated AMPK expression, moreover they ameliorated the hippocampal morphological alterations, GFAP and COX-2 immunoexpression.

Melatonin reverses cognitive deficits in streptozotocin-induced type 1 diabetes in the rat through attenuation of oxidative stress and inflammation

Uncontrolled diabetes mellitus (DM) is linked to attentional deficits and cognition deterioration. The neurohormone melatonin is an endogenous synchronizer of circadian rhythms with multiple protective properties. This research was designed to assess its effect against learning and memory decline in streptozotocin (STZ)-induced diabetic rats. Rats were assigned to control, melatonin-treated control, diabetic, and melatonin-treated diabetic groups. Melatonin was administered i.p. at a dose of 10 mg/kg/day for 47 days. Treatment of diabetic rats with melatonin reversed decline of spatial recognition memory in Y maze, performance of rats in novel object discrimination, and retention and recall in passive avoidance tasks. Furthermore, melatonin appropriately attenuated hippocampal malondialdehyde (MDA) and reactive oxygen species (ROS) and improved superoxide dismutase (SOD) activity and improved mitochondrial membrane potential (MMP) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) with no significant effect on nitrite, glutathione (GSH) and catalase activity. Besides, hippocampal level of acetylcholinesterase (AChE), glial fibrillary acidic protein (GFAP), nuclear factor-kappaB (NF-κB), interleukin 6 (IL-6) and tumor necrosis factor α (TNFα) decreased following melatonin treatment. There was also a reduction of dendritic spines of pyramidal neurons of hippocampal CA1 area in diabetic group that was significantly alleviated upon melatonin treatment. Melatonin could ameliorate learning and memory disturbances in diabetic rats through mitigation of cholinesterase activity, astrocytes, oxidative stress and inflammation and also via upregulation of some antioxidants in addition to its prevention of dendritic spine loss.

Inhibition of mTORC1 improves STZ-induced AD-like impairments in mice

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) share some pathological features, including tau hyperphosphorylation and deficits in insulin signaling, but the underlying mechanism and effective drugs for treating AD are unknown. The AD-like brain impairments are almost same in both of mouse type 2 DM models induced by the multiple low-dose intraperitoneal (i.p.) streptozotocin (STZ) injection and twice intracerebroventricular (i.c.v.) STZ injection. We found that memory disorders, impairment of insulin signaling, and AD-like tauopathies were exhibited in two different STZ-induced mouse models and that the level of Advanced Glycation End Products (AGEs) was increased in two STZ mouse models. Inhibition of mTORC1 with rapamycin reversed the deficits of insulin signaling associated kinases activity, decreased levels of AGEs and AD-like tau phosphorylation, and also improved memory deficit in both STZ mice. Rapamycin attenuated HG-induced tau hyperphosphorylation via the AKT/AMPK/GSK-3β pathways and p70S6K in SH-SY5Y cells. Taken together, these data demonstrated that rapamycin improved STZ-induced AD-like tauopathies and memory deficit in mice via improving p70S6K and AKT/AMPK/GSK-3β signaling and decreasing AGEs. Therefore, regulating insulin signaling via mTORC1 is a new strategy for preventing T2DM-associated AD, and mTORC1 is a potential drug target.

Assessment of Cognitive Phenotyping in Inbred, Genetically Modified Mice, and Transgenic Mouse Models of Alzheimer's Disease

Genetically modified mouse models are being used predominantly to understand brain functions and diseases. Well-designed and controlled behavioral analyses of genetically modified mice have successfully led to the identification of gene functions, understanding of brain diseases, and development of treatments. Recently, complex and higher cognitive functions have been examined in mice with genetic mutations. Therefore, research strategies for cognitive phenotyping should be sophisticated and evolve to convey the exact meaning of the findings and provide robust translational tools for testing hypotheses and developing treatments. This review addresses issues of experimental design and discusses studies that have examined cognitive function using mouse strain differences, genetically modified mice, and transgenic mice for Alzheimer's disease.

Antidiabetic treatment on memory and spatial learning: From the pancreas to the neuron

The detrimental effects of constant hyperglycemia on neural function have been quantitatively and qualitatively evaluated in the setting of diabetes mellitus. Some of the hallmark features of diabetic encephalopathy (DE) are impaired synaptic adaptation and diminished spatial learning capacity. Chronic and progressive cognitive dysfunction, perpetuated by several positive feedback mechanisms in diabetic subjects, facilitates the development of early-onset dementia and Alzheimer's disease. Despite the numerous clinical manifestations of DE having been described in detail and their pathophysiological substrate having been elucidated in both type 1 and type 2 diabetes mellitus, an effective therapeutic approach is yet to be proposed. Therefore, the aim of this review is to summarize the growing body of evidence concerning the effect of current antidiabetic treatment options on diabetic and non-DE.