Current Molecular Pharmacology - Current Issue

Arsenic is present in above permissible safe limits in groundwater, soil, and food, in various areas of the world. This is increasing exposure to humankind and affecting health in various ways. Alternation in cognition is one among them. Epidemiological research has reflected the impact of arsenic exposure on children in the form of diminished cognition.

Considering this fact, the present study reviewed the impact of arsenic on amyloid precursor protein, which is known to cause one of the commonest cognitive disorders such as Alzheimer’s disease.

The present study reviews the arsenic role in the generation of amyloid-beta from its precursor that leads to Alzheimer’s disease through the published article from Pubmed and Scopus.

According to the findings, regular, long-term exposure to arsenic beginning in infancy changes numerous arsenic level-regulating regions in the rat brain, which are related to cognitive impairments. Arsenic also affects the BBB clearance route by increasing RAGE expression. Arsenic triggers the proamyloidogenic pathway by increasing APP expression and subsequently, its processing by β-secretase and presenilin. Arsenic also affects mitochondrial dynamics, DNA repair pathway and epigenetic changes. The mechanism behind all these changes is explained in the present review article.

A raised level of arsenic exposure affects the amyloid precursor protein, a factor for the early precipitation of Alzheimer’s disease.

Activation of microglia and astrocytes has been observed in Alzheimer’s disease (AD). Transglutaminase 2 (TG2) is reported to be activated in AD and involved in cell proliferation, differentiation, and inflammation. Moreover, amyloid β (Aβ) aggregation is detected as a characteristic pathology in the AD brain, and is known to be a substrate of TG2. All-trans retinoic acid (ATRA) can modify cell proliferation and differentiation, and is reported to have therapeutic effects on AD pathology.

We aimed to assess the effects of ATRA in microglia and astrocytes on TG2 expression and glial functions.

After treatment with ATRA, TG2 expression and TG activity were assayed in both murine microglia BV-2 cells and cultured rat brain astrocytes. Endocytosis activity in BV-2 cells and Aβ aggregation by astrocytes conditioned medium were also assessed.

In both BV-2 cells and cultured astrocytes, ATRA increased TG2 expression and TG activity. The increase was blocked by AGN194310, an RA receptor antagonist. ATRA enhanced the endocytosis activity in BV-2 cells, and the addition of AGN194310 reversed it. The addition of cystamine, a competitive TG inhibitor, also reduced ATRA-enhanced endocytosis activity. On the other hand, Aβ aggregation was potentiated by ATRA-treated astrocytes conditioned medium compared to control astrocytes conditioned medium.

These results suggest that ATRA increased TG2 expression and TG activity via RA receptor in microglia and astrocytes. ATRA-enhanced TGs might be involved in phagocytosis and Aβ aggregation. Adequate control of TGs expression and function in microglia and astrocytes can be an important factor in AD pathology.

Ischemia/reperfusion injury (IRI) is a leading cause of acute kidney injury (AKI) that induces inflammation and oxidative stress. The main goal of the current study was to assess the impact of fingolimod on kidney IRI in rats.

For this purpose, 18 male Wistar rats (220–250g) were divided into three groups including (i) Sham, (ii) I/R, and (iii) fingolimod+I/R. The last group was pretreated with a single dose of fingolimod (1mg/kg) (intraperitoneal injection) before induction of the I/R injury. Kidney function, oxidative stress marker (malondialdehyde), and antioxidant markers (catalase, superoxide dismutase, glutathione, glutathione peroxidase, and total antioxidant capacity) were determined in the kidney tissue of the rats. Moreover, kidney samples were taken for histological analysis.

Fingolimod pre-treatment could significantly improve the glutathione peroxidase (p<0.01) and glutathione (p<0.001) activities along with the total antioxidant capacity levels (p<0.001) when compared to the I/R group. Moreover, significant recovery of kidney function and histology was seen in the fingolimod+ I/R group compared to the I/R group (p<0.01).

Fingolimod pretreatment could improve renal function, antioxidant capacity, and histological alterations after I/R injury. Hence, it might protect the kidney against IRI-related kidney damage including AKI and transplantation.

Cholangiopathies comprise a spectrum of diseases without curative treatments. Pharmacological treatments based on bile acid (BA) metabolism regulation represent promising therapeutic strategies for the treatment of cholangiopathies. Gentiopicroside (GPS), derived from the Chinese medicinal herb Gentianae Radix, exerts pharmacological effects on bile acid metabolism regulation and oxidative stress.

The present study aims to investigate the effect of GPS on 3,5-diethoxycarbonyl-1,4dihydrocollidine (DDC)-induced cholangiopathy.

Two independent animal experiments were designed to evaluate the comprehensive effect of GPS on chronic DDC diet-induced cholangiopathy, including bile duct obliteration, ductular reaction, BA metabolism reprogramming, liver fibrosis, oxidative stress and inflammatory responses.

In the first pharmacological experiment, three doses of GPS (5, 25 and 125 mg/kg) were injected intraperitoneally into mice fed a DDC diet for 14 days. DDC induced a typical ductular reaction, increased periductal fibrosis and mixed inflammatory cell infiltration in the portal areas. GPS treatment showed dose-dependent improvements in the ductular reaction, BA metabolism, fibrosis, oxidative stress and inflammatory response. In the second experiment, a high dose of GPS was injected intraperitoneally into control mice for 28 days, resulting in no obvious histologic changes and significant serologic abnormalities in liver function. However, GPS inhibited DDC-induced oxidative stress, serum and hepatic BA accumulation, proinflammatory cytokine production, and immunocyte infiltration. Specifically, the GPS-treated groups showed decreased infiltration of monocyte-derived macrophages and CD4+ and CD8+ T lymphocytes, as well as preserved Kupffer cells.

GPS alleviated chronic DDC diet-induced cholangiopathy disorder by improving the ductular reaction, periductal fibrosis, oxidative stress and inflammatory response. Its dosage-dependent pharmacological effects indicated that GPS warrants its further evaluation in clinical trials for cholangiopathy.

With the increasing risk of infections and other serious complications, the underlying molecular mechanism of wound healing impairment in diabetes deserves attention. Cold shock proteins (CSPs), including CIRP and RBM3 are highly expressed in the skin; however, it is unknown whether CSPs are involved in the wound-healing impairment of diabetic skin.

The objective of this study is to investigate the effects of RBM3 on skin wound healing in diabetes.

In vitro experiments, western blot assay was used to test the levels of proteins in HaCaT cells treated with different concentrations of glucose. RBM3 was over-expressed in HaCaT cells using lentivirus particles. Cell viability was analyzed by Cell-Counting Kit-8 assay and colony formation assay. The migration of HaCaT cells at different concentrations of glucose was evaluated by wound healing assay. In vivo experiments, the mouse model of diabetes was established by intraperitoneal injection of streptozotocin. Four weeks later, the mice were anesthetized by intraperitoneal injection of pentobarbital sodium for skin tissue collection or wound healing experiments. RBM3 knockout mice were established by removing exons 2–6 using the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technique and then used in skin wound healing experiments with or without diabetic stress.

In this study, the expression of RBM3, rather than CIRP, was altered in the skin of diabetic specimens, and the RBM3’s overexpression accelerated the cell viability and proliferation of HaCaT cells under high glucose conditions. RBM3 deficiency caused delayed wound healing in RBM3 knockout in diabetic conditions. Moreover. RBM3 enhanced the ERK1/2 signaling pathway, and its inhibitor FR180204 blocked the beneficial effect of RBM3 overexpression on skin wound healing in diabetes.

RBM3 activated the ERK1/2 signal to facilitate skin wound healing in diabetes, offering a novel therapeutic target for its treatment.

Mutations in the TP53 gene are the most common among genetic alterations in human cancers, resulting in the formation of mutant p53 protein (mutp53). Mutp53 promotes proliferation, migration, invasion, and metastasis in cancer cells. Not only does the initiation of oncogenesis ensue due to mutp53, but resistance towards chemotherapy and radiotherapy in cancer cells also occurs. This review aims to summarise and discuss the oncogenesis of mutant p53 in cancer cells and introduce the various mutant p53 inhibitors currently being evaluated at the pre-clinical and clinical stages. Compounds that induce the wild-type conformation on the targeted p53 missense mutation, restore or enhance the DNA binding of mutant p53, and inhibit cancer cells' growth are highlighted. In addition, the progression and development of the mutant p53 inhibitors in clinical trials are updated.

The progress of developing a cancer treatment that may successfully and efficiently target mutant p53 is on the verge of development. Mutant p53 proteins not only initiate oncogenesis but also cause resistance in cancer cells to certain chemo or radiotherapies, further endorse cancer cell survival and promote migration as well as metastasis of cancerous cells. With this regard, many mutant p53 inhibitors have been developed, some of which are currently being evaluated at the pre-clinical level and have been identified and discussed. To date, APR-246 is the most prominent one that has progressed to the Phase III clinical trial.

Research has revealed that the expression of PD-L1 is significantly upregulated in tumour cells and that the binding of programmed cell death protein 1 (PD-1) to programmed cell death 1 ligand 1 (PD-L1) inhibits the response of T cells, thereby suppressing tumour immunity. Therefore, blocking PD-L1/PD-1 signalling has become an important target in clinical immunotherapy. Some old drugs, namely, non-anticancer drugs, have also been found to have antitumour effects, and maprotiline is one of them. Maprotiline is a tetracyclic antidepressant that has been widely used to treat depression. However, it has not yet been reported whether maprotiline can exert an antitumour effect on melanoma.

This study aimed to investigate the antitumour efficacy of maprotiline in mice with melanoma.

In this study, female C57BL/6 mice were used to establish a tumour-bearing animal model. After treatment with maprotiline, the survival rate of mice was recorded daily. The expression of relevant proteins was detected by Western blotting, the proportion of immune cells was detected by flow cytometry, and the infiltration of immune cells in tumour tissue was detected by immunofluorescence staining.

Maprotiline was found to inhibit the proliferation and migration of B16 cells while increasing cell apoptosis. Importantly, treatment with maprotiline decreased the expression of PD-L1 and increased the proportion of CD4⁺ T cells, CD8⁺ T cells, and NK cells in the spleen. It also increased the infiltration of CD4⁺ and CD8⁺ T cells in tumour tissue.

Our research findings suggest that maprotiline enhances the antitumour immune response in mouse melanoma by inhibiting PD-L1 expression. This study may discover a new PD-L1 inhibitor, providing a novel therapeutic option for the clinical treatment of tumours.

Colorectal cancer remains a life-threatening malignancy with increasing morbidity and mortality worldwide. Therefore, new and effective anti-colorectal cancer therapeutics are urgently needed.

In this study, we have studied the anti-tumor properties and potential mechanisms of PF-04449913. Colorectal cancer cell viability was reduced by PF-04449913 in a dose-dependent manner. The migration and invasion ability of malignant colon cells were attenuated by the drug, as demonstrated by the Transwell test. Moreover, PF-04449913 repressed the phosphorylation levels of ERK and other proteins, and the expression levels of MMP9. The anti-tumor effects of the drug in vivo were demonstrated in BALB/c-nude mice models, and PF-04449913 inhibited the malignant phenotype of colorectal cancer cells, including reduction of tumor size and promotion of apoptosis. At the molecular level, PF-04449913 induced a significant decrease in ERK and p65 protein phosphorylation levels and inhibited MMP9 protein expression.

Both in vivo and in vitro results showed PF-04449913 to demonstrate antitumor effects, which have been proposed to be mediated through blockade of the ERK/p65 signaling pathway, and subsequent repression of MMP9 expression.

Our study provides a new perspective on the potential clinical application of PF-04449913 in the treatment of colorectal cancer.

The potential mechanism underlying the protective effect of Astragaloside IV (AS-IV) co-treatment with 1, 25-dihydroxy-vitamin D (Vit-D) on neuropathy in diabetic high-fat rats was investigated.

The rat diabetic hyperlipidemia (DH) model was established via streptozotocin and a high-fat diet (HFD). After co-treatment (of AS-IV and Vit-D at respective doses of 50 mg/kg via oral gavage and 30000 IU/kg via intramuscular injection), blood glucose levels, markers of inflammation and oxidative stress, as well as apoptosis and histopathology were evaluated with appropriate techniques.

Co-treatment could effectively reduce blood glucose levels substantially (p< 0.01), improve weight loss, and decrease oral glucose tolerance. Reduced respective sensory and motor nerve conduction velocities in rats were substantially improved (p<0.01) after co-treatment. Also, we observed obvious improvement in DH-induced injured nerve fiber myelin structure and other organ pathologies in co-treated rats. Besides, we observed up-regulated expressions of peroxisomal-proliferator activated receptor-alpha (PPAR-α) and Vit-D receptors (VDR) (p< 0.01) through the western blotting technique. Using the same technique, we also discovered reduced levels of interleukin (IL)1 beta, IL-6, and tumor necrosis factor-alpha, coupled with increased IL-10 and superoxide dismutase levels (p< 0.01). Importantly, co-treatment could effectively exert anti-oxidative and anti-inflammatory effects. Also, co-treatment resulted in the up-regulation of PPAR-α and VDR expressions, inhibition of the renin–angiotensin–aldosterone system, and promotion of β-cell sensitivity to insulin.

The combined application of AS-IV and Vit-D exhibited health effects such as anti-oxidation, regulation of inflammatory factors, and promotion of cell repair, which may be considered as the mechanisms underlying treatment of diabetic peripheral neuropathy and improvement in biochemical indicators.

Artemisinin (ART) is mainly derived from Artemisia annua, a traditional Chinese medicinal plant, and has been found to affect cellular biochemical processes, such as proliferation, angiogenesis, and apoptosis, in addition to its antimalarial properties. However, its effect on cardiac hypertrophy and the underlying mechanisms remain unclear.

This study aimed to investigate the effect of ART on cardiac hypertrophy and explore its possible mechanisms.

A rat model was established by intraperitoneal injection of isoproterenol (ISO) for 3 days, and the degree of myocardial hypertrophy was compared among 5 groups: a control (CON) group, an ISO group, and groups treated with different doses of ART (7 mg/kg/d, 35 mg/kg/d, and 75 mg/kg/d). Echocardiography was used to evaluate cardiac function and structure. The cross-sectional area of cardiomyocytes was measured by hematoxylin and eosin (H&E) staining. The heart weight (HW), body weight (BW), and tail length were measured, and the HW/tail length ratio and the HW/BW ratio were calculated. H9c2 rat cardiomyocytes were cultured, and different amounts of ART were added 2 hours before ISO stimulation. Phalloidin staining was used to evaluate the degree of cell hypertrophy. The levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were quantified in rat plasma and cell supernatant using enzyme-linked immunosorbent assay (ELISA), while the expression levels of p-ERK1/2, p-JNK, and p-p38 MAPK were assessed in the myocardium and H9c2 cells via western blot analysis.

Intragastric administration of ART at a dosage of 35 mg/kg/d or over mitigated the early-stage cardiac hypertrophy induced by ISO in rats led to a reduction in left ventricular posterior wall diastolic thickness, interventricular septal thickness at diastole, lowered ANP and BNP levels, as well as a decrease in HW/tail length and HW/BW ratio. In vitro studies demonstrated that ART at a concentration of 100 μM inhibited ISO-mediated hypertrophy of H9c2 cells. The ISO group showed a higher p-ERK/GAPDH ratio and p-p38 MAPK/GAPDH ratio than the control group both in vivo and in vitro. Although the p-JNK/GAPDH ratio was increased in the ISO group, there was no statistical difference. The p-ERK/GAPDH and p-p38/GAPDH ratios were significantly lower in the ART group than in the ISO group.

The mechanism of ART against cardiac hypertrophy was related to inhibition of the ERK1/2 and p38 MAPK signaling pathways.