The glucagon-like peptide-1 analogue exendin-4 reverses impaired intracellular Ca(2+) signalling in steatotic hepatocytes

Calreticulin regulates hepatic stellate cell activation through modulating TGF-beta-induced Smad signaling

Liver fibrosis is characterized by excessive deposition of extracellular matrix (ECM) as a wound healing process. Activated hepatic stellate cells (HpSCs) are the major producer of the ECM and play a central role in liver fibrogenesis. It has been widely accepted that elimination of activated HpSCs or reversion to a quiescent state can be a feasible strategy for resolving the disease, further highlighting the urgent need for novel therapeutic targets. Calreticulin (CRT) is a molecular chaperone that normally resides in the endoplasmic reticulum (ER), important in protein folding and trafficking through the secretory pathway. CRT also plays a critical role in calcium (Ca2+) homeostasis, with its Ca2+ storage capacity. In the current study, we aimed to demonstrate its function in directing HpSC activation. In a mouse liver injury model, CRT was up-regulated in HpSCs. In cellular experiments, we further showed that this activation was through modulating the canonical TGF-β signaling. As down-regulation of CRT in HpSCs elevated intracellular Ca2+ levels through a form of Ca2+ influx, named store-operated Ca2+ entry (SOCE), we examined whether moderating SOCE affected TGF-β signaling. Interestingly, blocking SOCE had little effect on TGF-β-induced gene expression. In contrast, inhibition of ER Ca2+ release using the inositol trisphosphate receptor inhibitor 2-APB increased TGF-β signaling. Treatment with 2-APB did not alter SOCE but decreased intracellular Ca2+ at the basal level. Indeed, adjusting Ca2+ concentrations by EGTA or BAPTA-AM chelation further enhanced TGF-β-induced signaling. Our results suggest a crucial role of CRT in the liver fibrogenic process through modulating Ca2+ concentrations and TGF-β signaling in HpSCs, which may provide new information and help advance the current discoveries for liver fibrosis.

Calcium signalling in hepatic metabolism: Health and diseases

The flexibility between the wide array of hepatic functions relies on calcium (Ca2+) signalling. Indeed, Ca2+ is implicated in the control of many intracellular functions as well as intercellular communication. Thus, hepatocytes adapt their Ca2+ signalling depending on their nutritional and hormonal environment, leading to opposite cellular functions, such as glucose storage or synthesis. Interestingly, hepatic metabolic diseases, such as obesity, type 2 diabetes and non-alcoholic fatty liver diseases, are associated with impaired Ca2+ signalling. Here, we present the hepatocytes' toolkit for Ca2+ signalling, complete with regulation systems and signalling pathways activated by nutrients and hormones. We further discuss the current knowledge on the molecular mechanisms leading to alterations of Ca2+ signalling in hepatic metabolic diseases, and review the literature on the clinical impact of Ca2+-targeting therapeutics.

A Systematic Review and Meta-Analysis of Continuous Subcutaneous Insulin Infusion vs. Multiple Daily Injections in Type-2 Diabetes

Diabetes mellitus (DM) has a growing prevalence worldwide, even in developing countries. Many antidiabetic agents are used to improve glycemic control; however, in cases of an insufficient outcome, insulin is administered. Yet, the timing of proper insulin administration is still a subject of intense research. To date, there have been no recommendations or guidelines for the use of continuous subcutaneous insulin infusion (CSII) in Type 2 Diabetes Mellitus (T2DM). In the present study, we have performed a meta-analysis to evaluate the use of CSII in patients with T2DM. An extensive literature search was conducted through the electronic databases Pubmed, Clinicaltrials.gov, and Cochrane Central Register of Controlled Trials (CENTRAL) from October 2019-May 2022, for interventional studies related to T2DMI and CSII versus multiple daily injections (MDI). We included articles published in the English language only, yielding a total of thirteen studies. We found better outcomes in patients receiving CSII, in regard to glycated hemoglobin (HbA1c) and total insulin dose. In contrast, fasting plasma glucose and body weight did not show statistically significant differences between the two groups. Our analyses showed that CSII could be beneficial in patients with T2DM in order to achieve their glucose targets.

GLP-1 mimetics as a potential therapy for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), as a severe form of nonalcoholic fatty liver disease (NAFLD), is characterized by liver steatosis, inflammation, hepatocellular injury and different degrees of fibrosis. The pathogenesis of NASH is complex and multifactorial, obesity and type 2 diabetes mellitus (T2DM) have been implicated as major risk factors. Glucagon-like peptide-1 receptor (GLP-1R) is one of the most successful drug targets of T2DM and obesity, and its peptidic ligands have been proposed as potential therapeutic agents for NASH. In this article we provide an overview of the pathophysiology and management of NASH, with a special focus on the pharmacological effects and possible mechanisms of GLP-1 mimetics in treating NAFLD/NASH, including dual and triple agonists at GLP-1R, glucose-dependent insulinotropic polypeptide receptor or glucagon receptor.

Emerging Nanotherapeutic Approaches to Overcome Drug Resistance in Cancers with Update on Clinical Trials

A key issue with modern cancer treatments is the emergence of resistance to conventional chemotherapy and molecularly targeted medicines. Cancer nanotherapeutics were created in order to overcome the inherent limitations of traditional chemotherapeutics. Over the last few decades, cancer nanotherapeutics provided unparalleled opportunities to understand and overcome drug resistance through clinical assessment of rationally designed nanoparticulate delivery systems. In this context, various design strategies such as passive targeting, active targeting, nano-drug, and multimodal nano-drug combination therapy provided effective cancer treatment. Even though cancer nanotherapy has made great technological progress, tumor biology complexity and heterogeneity and a lack of comprehensive knowledge of nano-bio interactions remain important roadblocks to future clinical translation and commercialization. The current developments and advancements in cancer nanotherapeutics employing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are discussed in this article. There is also a review of various nanotherapeutics-based approaches to cancer therapy, including targeting strategies for the tumor microenvironment and its components, advanced delivery systems for specific targeting of cancer stem cells (CSC), as well as exosomes for delivery strategies, and an update on clinical trials. Finally, challenges and the future perspective of the cancer nanotherapeutics to reverse cancer drug resistance are discussed.

New treatment approaches for Alzheimer's disease: preclinical studies and clinical trials centered on antidiabetic drugs

INTRODUCTION

Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) represent two major chronic diseases that affect a large percentage of the population and share common pathogenetic mechanisms, including oxidative stress and inflammation. Considering their common mechanistic aspects, and given the current lack of effective therapies for AD, accumulating research has focused on the therapeutic potential of antidiabetic drugs in the treatment or prevention of AD.

AREAS COVERED

This review examines the latest preclinical and clinical evidence on the potential of antidiabetic drugs as candidates for AD treatment. Numerous approved drugs for T2DM, including insulin, metformin, glucagon-like peptide-1 receptor agonists (GLP-1 RA), and sodium glucose cotransporter 2 inhibitors (SGLT2i), are in the spotlight and may constitute novel approaches for AD treatment.

EXPERT OPINION

Among other pharmacologic agents, GLP-1 RA and SGLT2i have so far exhibited promising results as novel treatment approaches for AD, while current research has centered on deciphering their action on the central nervous system (CNS). Further investigation is crucial to reveal the most effective pharmacological agents and their optimal combinations, maximize their beneficial effects on neurons, and find ways to increase their distribution to the CNS.

Emerging Roles of Calcium Signaling in the Development of Non-Alcoholic Fatty Liver Disease

The liver plays a central role in energy metabolism. Dysregulated hepatic lipid metabolism is a major cause of non-alcoholic fatty liver disease (NAFLD), a chronic liver disorder closely linked to obesity and insulin resistance. NAFLD is rapidly emerging as a global health problem with currently no approved therapy. While early stages of NAFLD are often considered benign, the disease can progress to an advanced stage that involves chronic inflammation, with increased risk for developing end-stage disease including fibrosis and liver cancer. Hence, there is an urgent need to identify potential pharmacological targets. Ca²⁺ is an essential signaling molecule involved in a myriad of cellular processes. Intracellular Ca²⁺ is intricately compartmentalized, and the Ca²⁺ flow is tightly controlled by a network of Ca²⁺ transport and buffering proteins. Impaired Ca²⁺ signaling is strongly associated with endoplasmic reticulum stress, mitochondrial dysfunction and autophagic defects, all of which are etiological factors of NAFLD. In this review, we describe the recent advances that underscore the critical role of dysregulated Ca²⁺ homeostasis in lipid metabolic abnormalities and discuss the feasibility of targeting Ca²⁺ signaling as a potential therapeutic approach.

Wogonin and alleviation of hyperglycemia via inhibition of DAG mediated PKC expression. A brief insight

Protein kinase C (PKC) is a family of protein kinase enzymes that can phosphorylate other proteins and influence their functions, such as signal transduction, cell survival, and death. Increased diacylglycerol (DAG) concentrations, which are typically observed raised in hyperglycemic situations such as diabetes mellitus, can also activate PKC enzymes (DM). On the other hand, PKC isomers have been shown to play an essential role in diabetes and many hyperglycemic complications, most importantly atherosclerosis and diabetic cardiomyopathy (DCM). As a result, blocking PKC activation via DAG can prevent hyperglycemia and related consequences, such as DCM. Wogonin is a herbal medicine which has anti-inflammatory properties, and investigations show that it scavenge oxidative radicals, attenuate nuclear factor-kappa B (NF-κB) activity, inhibit several essential cell cycle regulatory genes, block nitric oxide (NO) and suppress cyclooxygenase-2 (COX-2). Furthermore, several investigations show that wogonin also attenuates diacylglycerol DAG levels in diabetic mice. Since the DAG-PKC pathway is linked with hyperglycemia and its complications, Wogonin-mediated DAG-PKC attenuation can help treat hyperglycemia and its complications.

Differential lysophosphatidylcholine acyltransferase 1 (LPCAT1) expression confers aggressiveness and independently predicts recurrence in bladder urothelial carcinomas

Bladder urothelial carcinomas are diverse in terms of biological behavior and this reflects the underlying complex metabolic and molecular pathways. Novel biomarkers that could assist in the management and outcome prediction of bladder urothelial carcinomas are eagerly needed. Recently, overexpression of lysophosphatidylcholine acyltransferase 1 (LPCAT1), a key enzyme in lipid metabolism, has been implicated in the evolvement of several tumors. In this study, LPCAT1 immunohistochemical expression was evaluated and statistically analyzed in 60 bladder urothelial carcinomas in relation to other clinicopathological parameters including the patient outcome. Twenty non-neoplastic bladder tissues served as a control group. Cases were followed up for a mean period of 9 months. LPCAT1 was expressed in all bladder urothelial carcinoma cases with two distinct patterns designated as high and low nuclear expression. Low LPCAT1 nuclear expression was detected in urothelial carcinoma cases as compared to the control group. Similarly, low nuclear expression of LPCAT1 was associated with high grade and invasive tumors and could independently predict tumor recurrence and short survival. In conclusion, LPCAT1 downregulation might be involved in bladder urothelial carcinoma tumorigenesis and could contribute to tumor aggressive phenotype. Retained LPCAT1 expression is an independent predictor of tumor recurrence and it represents a promising prognostic marker for patients' risk stratification.

Impaired Ca2+ signaling due to hepatic steatosis mediates hepatic insulin resistance in Alström syndrome mice that is reversed by GLP-1 analog treatment

Ca²⁺ signaling plays a critical role in the regulation of hepatic metabolism by hormones including insulin. Changes in cytoplasmic Ca²⁺ regulate synthesis and posttranslational modification of key signaling proteins in the insulin pathways. Emerging evidence suggests that hepatocyte intracellular Ca²⁺ signaling is altered in lipid-loaded liver cells isolated from obese rodent models. The mechanisms of altered Ca²⁺-insulin and insulin-Ca²⁺ signaling pathways in obesity remain poorly understood. Here, we show that the kinetics of insulin-initiated intracellular (initial) Ca²⁺ release from endoplasmic reticulum is significantly impaired in steatotic hepatocytes from obese Alström syndrome mice. Furthermore, exenatide, a glucagon-like peptide-1 (GLP-1) analog, reversed lipid-induced inhibition of intracellular Ca²⁺ release kinetics in steatotic hepatocytes, without affecting the total content of intracellular Ca²⁺ released. Exenatide reversed the lipid-induced inhibition of intracellular Ca²⁺ release, at least partially, via lipid reduction in hepatocytes, which then restored hormone-regulated cytoplasmic Ca²⁺ signaling and insulin sensitivity. This data provides additional evidence for the important role of Ca²⁺ signaling pathways in obesity-associated impaired hepatic lipid homeostasis and insulin signaling. It also highlights a potential advantage of GLP-1 analogs when used to treat type 2 diabetes associated with hepatic steatosis.

Molecular Characterization of Carbonic Anhydrase II (CA II) and Its Potential Involvement in Regulating Shell Formation in the Pacific Abalone, Haliotis discus hannai

Carbonic anhydrases (CAs) are a family of metalloenzymes that can catalyze the reversible interconversion of CO₂/HCO₃^–, ubiquitously present in both prokaryotes and eukaryotes. In the present study, a CA II (designated as HdhCA II) was sequenced and characterized from the mantle tissue of the Pacific abalone. The complete sequence of HdhCA II was 1,169 bp, encoding a polypeptide of 349 amino acids with a NH₂-terminal signal peptide and a CA architectural domain. The predicted protein shared 98.57% and 68.59% sequence identities with CA II of Haliotis gigantea and Haliotis tuberculata, respectively. Two putative N-linked glycosylation motifs and two cysteine residues could potentially form intramolecular disulfide bond present in HdhCA II. The phylogenetic analysis indicated that HdhCA II was placed in a gastropod clade and robustly clustered with CA II of H. gigantea and H. tuberculata. The highest level of HdhCA II mRNA expression was detected in the shell forming mantle tissue. During ontogenesis, the mRNA of HdhCA II was detected in all stages, with larval shell formation stage showing the highest expression level. The in situ hybridization results detected the HdhCA II mRNA expression in the epithelial cells of the dorsal mantle pallial, an area known to express genes involved in the formation of a nacreous layer in the shell. This is the first report of HdhCA II in the Pacific abalone, and the results of this study indicate that this gene might play a role in the shell formation of abalone.

Carbonic Anhydrase in Pacific Abalone Haliotis discus hannai: Characterization, Expression, and Role in Biomineralization

Carbonic anhydrases (CAs) are universal zinc ion containing metalloenzymes that play a pivotal role in various physiological processes. In this study, a CA I (designated as Hdh CA I) was isolated and characterized from the mantle tissue of Pacific abalone, Haliotis discus hannai. The full-length cDNA sequence of Hdh CA I was 1,417-bp in length, encoding a protein of 337 amino acids with molecular weight of 37.58 kDa. Hdh CA I sequence possessed a putative signal peptide of 22 amino acids and a CA catalytic function domain. The predicted protein shared 94 and 78% sequence identities with Haliotis gigantea and Haliotis tuberculata CA I, respectively. Results of phylogenetic analysis indicated that Hdh CA I was evolutionarily close to CA I of H. gigantea and H. tuberculata with high bootstrap values. Significantly higher levels of Hdh CA I mRNA transcript were found in mantle than other examined tissues. In situ hybridization results showed strong hybridization signals in epithelial cells of the dorsal mantle pallial, an area known to synthesize and secrete proteins responsible for the nacreous layer formation of shell. This is the first study on Hdh CA I in H. discus hannai and the results may contribute to further study its physiological functions in shell biomineralization of abalone.

Characterization of Insulin-Like Growth Factor Binding Protein 7 (Igfbp7) and Its Potential Involvement in Shell Formation and Metamorphosis of Pacific Abalone, Haliotis discus hannai

Insulin-like growth factor binding proteins (IGFBPs) are secreted proteins that play an important role in IGF regulation of growth and development of vertebrate and invertebrates. In this study, the IGFBP7 gene was cloned and characterized from mantle tissues of H. discus hannai, and designated as Hdh IGFBP7. The full-length cDNA sequence transcribed from the Hdh IGFBP7 gene was 1519-bp long with an open reading frame of 720-bp corresponding to a putative polypeptide of 239 amino acids. The molecular mass of its mature protein was approximately 23.44 KDa with an estimated isoelectric point (pI) of 5.35, and it shared significant homology with IGFBP7 gene of H. madaka. Hdh IGFBP7 has a characteristic IGFBP N-terminal domain (22–89 aa), a kazal-type serine proteinase inhibitor domain (77–128), and an immunoglobulin-like C2 domain (144–223). Furthermore, twelve cysteine residues and a signature motif of IGFBPs (XCGCCXXC) were found in its N-terminal domain. Phylogenetic analysis revealed that Hdh IGFBP7 was aligned with IGFBP7 of H. madaka. Tissue distribution analysis showed that the mRNA of Hdh IGFBP7 was expressed in all examined tissues, with the highest expression level observed in the mantle and gill tissues. The expression level of Hdh IGFBP7 mRNA was relatively higher at the juvenile stage during its metamorphosis period. In situ hybridization showed that Hdh IGFBP7 transcript was expressed in epithelial cells of the dorsal mantle pallial and mucus cells of the branchial epithelium in gill. These results provide basic information for future studies on the role of IGFBP7 in IGF regulation of shell growth, development and metamorphosis of abalone.

Characterization of Insulin-Like Growth Factor Binding Protein-5 (IGFBP-5) Gene and Its Potential Roles in Ontogenesis in the Pacific Abalone, Haliotis discus hannai

Insulin-like growth factor binding protein family is known to be involved in regulating biological actions of insulin-like growth factors (IGFs). In the present study, a full-length cDNA encoding the IGFBP-5 gene was cloned and characterized from the cerebral ganglion of Haliotis discus hannai. The 921-bp full-length sequence of Hdh IGFBP-5 cDNA transcript had an open reading frame of 411 bp encoding a predicted polypeptide of 136 amino acids, sharing high sequence identities with IGFBP-5 of H. diversicolor. The deduced Hdh IGFBP-5 protein contained a putative transmembrane domain (13-35 aa) in the N-terminal region. It also possessed a signature domain of IGFBP protein family (IB domain, 45-120 aa). Six cysteine residues (Cys-47, Cys-55, Cys-73, Cys-85, Cys-98, and Cys-118) in this cloned sequence could potentially form an intrachain disulfide bond. Phylogenetic analysis indicated that the Hdh IGFBP-5 gene was robustly clustered with IGFBP-5 of H. diversicolor. Tissue distribution analysis based on qPCR assay showed that Hdh IGFBP-5 was widely expressed in all examined tissues, with significantly (p < 0.05) higher expression in the cerebral ganglion. In male and female gametogenetic cycles, Hdh IGFBP-5 mRNA was expressed at all stages, showing significantly higher level at ripening stage. The expression level of Hdh IGFBP-5 mRNA was significantly higher in the polar body stage than in other ontogenic stages. In situ hybridization revealed that Hdh IGFBP-5 mRNA was present in the neurosecretory cells of the cerebral ganglion. This is the first study describing IGFBP-5 in H. discus hannai that might be synthesized in the neural ganglia. Our results demonstrate Hdh IGFBP-5 is involved in regulating ontogenic development and reproductive regulation of H. discus hannai.

Molecular Identification, Characterization, and Expression Analysis of a Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Pacific Abalone, Haliotis discus hannai

A full-length cDNA sequence encoding a GnRH receptor was cloned from the pleuropedal ganglion of the Pacific abalone, Haliotis discus hannai. The cloned sequence is 1499-bp in length encoding a protein of 460 amino acid residues, with a molecular mass of 52.22 kDa and an isoelectric point (pI) of 9.57. The architecture of HdhGnRH-R gene exhibited key features of G protein-coupled receptors (GPCRs), including seven membrane spanning domains, putative N-linked glycosylation motifs, and phosphorylation sites of serine and threonine residues. It shared 63%, 52%, and 30% sequence identities with Octopus vulgaris, Limulus polyphemus, and Mizuhopecten yessoensis GnRH-R II sequences, respectively. Phylogenetic analysis indicated that HdhGnRH-R gene was clustered with GnRH-R II of O. vulgaris and O. bimaculoides. qPCR assay demonstrated that the mRNA expression level of this receptor was significantly higher in the pleuropedal ganglion than that in any other examined tissue. Transcriptional activities of this gene in gonadal tissues were significantly higher in the ripening stage. The mRNA expression of this gene was significantly higher in pleuropedal ganglion, testis, and ovary at higher effective accumulative temperature (1000 °C). In situ hybridization revealed that HdhGnRH-R mRNA was expressed in neurosecretory cells of pleuropedal ganglion. Our results suggest that HdhGnRH-R gene synthesized in the neural ganglia might be involved in the control of gonadal maturation and gametogenesis of H. discus hannai. This is the first report of GnRH-R in H. discus hannai and the results may contribute to further studies of GPCRs evolution or may useful for the development of aquaculture method of this abalone species.

Neurotrophins and glial cell line-derived neurotrophic factor in the ovary: physiological and pathophysiological implications

BACKGROUND

Neurotrophins [nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4)] and glial cell line-derived neurotrophic factor (GDNF) are soluble polypeptide growth factors that are widely recognized for their roles in promoting cell growth, survival and differentiation in several classes of neurons. Outside the nervous system, neurotrophin (NT) and GDNF signaling events have substantial roles in various non-neural tissues, including the ovary.

OBJECTIVE AND RATIONALE

The molecular mechanisms that promote and regulate follicular development and oocyte maturation have been extensively investigated. However, most information has been obtained from animal models. Even though the fundamental process is highly similar across species, the paracrine regulation of ovarian function in humans remains poorly characterized. Therefore, this review aims to summarize the expression and functional roles of NTs and GDNF in human ovarian biology and disorders, and to describe and propose the development of novel strategies for diagnosing, treating and preventing related abnormalities.

SEARCH METHODS

Relevant literature in the English language from 1990 to 2018 describing the role of NTs and GDNF in mammalian ovarian biology and phenotypes was comprehensively selected using PubMed, MEDLINE and Google Scholar.

OUTCOMES

Studies have shown that the neurotrophins NGF, BDNF, NT-3 and NT-4 as well as GDNF and their functional receptors are expressed in the human ovary. Recently, gathered experimental data suggest putative roles for NT and GDNF signaling in the direct control of ovarian function, including follicle assembly, activation of the primordial follicles, follicular growth and development, oocyte maturation, steroidogenesis, ovulation and corpus luteum formation. Additionally, crosstalk occurs between these ovarian regulators and the endocrine signaling system. Dysregulation of the NT system may negatively affect ovarian function, leading to reproductive pathology (decreased ovarian reserve, polycystic ovary syndrome and endometriosis), female infertility and even epithelial ovarian cancers.

WIDER IMPLICATIONS

A comprehensive understanding of the expression, actions and underlying molecular mechanisms of the NT/GDNF system in the human ovary is essential for novel approaches to therapeutic and diagnostic interventions in ovarian diseases and to develop more safe, effective methods of inducing ovulation in ART in the treatment of female infertility.

Rice black-streaked dwarf virus P10 suppresses protein kinase C in insect vector through changing the subcellular localization of LsRACK1

Rice black-streaked dwarf virus (RBSDV) was known to be transmitted by the small brown planthopper (SBPH) in a persistent, circulative and propagative manner in nature. Here, we show that RBSDV major outer capsid protein (also known as P10) suppresses the protein kinase C (PKC) activity of SBPH through interacting with the receptor for activated protein kinase C 1 (LsRACK1). The N terminal of P10 (amino acids (aa) 1-270) and C terminal of LsRACK1 (aa 268-315) were mapped as crucial for the interaction. Confocal microscopy and subcellular fractionation showed that RBSDV P10 fused to enhanced green fluorescent protein formed vesicular structures associated with endoplasmic reticulum (ER) membranes in Spodoptera frugiperda nine cells. Our results also indicated that RBSDV P10 retargeted the initial subcellular localization of LsRACK1 from cytoplasm and cell membrane to ER and affected the function of LsRACKs to activate PKC. Inhibition of RACK1 by double stranded RNA-induced gene silencing significantly promoted the replication of RBSDV in SBPH. In addition, the PKC pathway participates in the antivirus innate immune response of SBPH. This study highlights that RACK1 negatively regulates the accumulation of RBSDV in SBPH through activating the PKC signalling pathway, and RBSDV P10 changes the subcellular localization of LsRACK1 and affects its function to activate PKC. This article is part of the theme issue 'Biotic signalling sheds light on smart pest management'.

Targeting cancer cells with nanotherapeutics and nanodiagnostics: Current status and future perspectives

Nanotechnology is reshaping health care strategies and is expected to exert a tremendous impact in the coming years offering better healthcare facilities. It has led to not only therapeutic drug delivery feasibility but also to diagnostics. Materials in the size of nano range (1-100 nm) used in the design, fabrication, regulation, and application of therapeutic drugs or devices are classified as medical nanotechnology and nanopharmacology. Delivery of more complex molecules to the specific site of action as well as gene therapy has pushed forward the nanoparticle-based drug delivery to its maximum. Areas that benefit from nano-based drug delivery systems are cancer, diabetes, infectious diseases, neurodegenerative diseases, blood disorders and orthopedic-related ailments. Moreover, development of nanotherapeutics with multi-functionalities has a considerable potential to fill the gaps that exist in the present therapeutic domain. In cancer treatment, nanomedicines have superiority over current therapeutic practices as they can effectively deliver the drug to the affected tissues, thus reducing drug toxicities. Along this line, polymeric conjugates of asparaginase and polymeric micelles of paclitaxel have recently been recommended for the treatment of various types of cancers. Nanotechnology-based therapeutics and diagnostics provide greater effectiveness with less or no toxicity concerns. Similarly, diagnostic imaging holds promising future applications with newer nano-level imaging elements. Advancements in nanotechnology have emerged to a newer direction which use nanorobotics for various applications in healthcare. Accordingly, this review comprehensively highlights the potentialities of various nanocarriers and nanomedicines for multifaceted applications in diagnostics and drug delivery, especially the potentialities of polymeric nanoparticle, nanoemulsion, solid-lipid nanoparticle, nanostructured lipid carrier, self-micellizing anticancer lipids, dendrimer, nanocapsule and nanosponge-based therapeutic approaches in the field of cancer. Furthermore, this article summarizes the most recent literature pertaining to the use of nano-technology in the field of medicine, particularly in treating cancer patients.

Regulation of the SIRT1 signaling pathway in NMDA-induced Excitotoxicity

Silent Information Regulator 1 (SIRT1), an NAD⁺-dependent deacetylase, contributes to the neuroprotective effect. However, intracellular signaling pathways that affect SIRT1 function remain unknown. It is well known that N-methyl-D-aspartate (NMDA) receptor activation induces calcium influx which then activates PKC, and SIRT1 is a mRNA target for HuR protein. We hypothesize that Ca²⁺-PKC-HuR-SIRT1 pathway modulates SIRT1 function. The present study is to investigate the potential pathway of SIRT1 in the SH-SY5Y cell line as an in vitro model of NMDA-induced neurotoxicity. The results showed that: (1) SIRT1 levels were downregulated in NMDA model; (2) NMDA induced an increase in serine phosphorylation of HuR, while inhibition of serine phosphorylation of HuR increased SIRT1 levels, promoting cell survival; (3) PKC inhibitor (Gö 6976) reversed NMDA insults and also suppressed serine phosphorylation of HuR; (4) 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular calcium chelator, fully reversed NMDA insults and also inhibited PKC activity evoked by NMDA. These results indicate that intracellular elevated Ca²⁺ activates PKC, which phosphorylates HuR and then promotes SIRT1 mRNA decay and subsequent neuronal death in NMDA model. Therefore, the study suggests that inhibition of Ca²⁺-PKC-HuR-SIRT1 pathway could be an effective strategy for preventing certain neurological diseases related to NMDA excitotoxicity.

Identification, characterization, and expression analysis of a serotonin receptor involved in the reproductive process of the Pacific abalone, Haliotis discus hannai

Serotonin receptor (5-HT) is a biogenic amine acting as a neurotransmitter and neuromodulator that mediates various aspects of reproduction and gametogenesis. The full-length nucleotide sequence of Haliotis discus hannai encodes a protein of 417 amino acids with a predicted molecular mass of 46.54 kDa and isoelectric point of 8.94. The structural profile of 5-HT_Hdh displayed key features of G protein-coupled receptors, including seven hydrophobic transmembrane domains, putative N-linked glycosylation sites, and several phosphorylation consensus motifs. It shares the highest homology of its amino acid sequence with the 5-HT receptor from Haliotis asinina, and to lesser extent of human 5-HT receptor. The cloned sequence possesses two cysteine residues (Cys-115 and Cys-193), which are likely to form a disulfide bond. Phylogenetic comparison with other known 5-HT receptor genes revealed that the 5-HT_Hdh is most closely related to the 5-HT_Ha receptor. The three-dimensional structure of the 5-HT_Hdh showed multiple alpha helices which is separated by a helix-loop-helix (HLH) structure. Quantitative PCR demonstrated that the receptor mRNA was predominantly expressed in the pleuropedal ganglion. Significant differences in the transcriptional activity of the 5-HT_Hdh gene were observed in the ovary at the ripening stage. An exclusive expression was detected in pleuropedal ganglion, testis, and ovary at higher effective accumulative temperature (1000 °C). In situ hybridization showed that the 5-HT_Hdh expressing neurosecretory cells were distributed in the cortex of the pleuropedal ganglion. Our results suggest that 5-HT_Hdh synthesized in the neural ganglia may be involved in oocyte maturation and spawning of H. discus hannai.

N-arylpiperazine-containing compound (C2): An enhancer of sunitinib in the treatment of pancreatic cancer, involving D1DR activation

Previous studies showed that dopamine (DA) significantly reduces the frequency of cancer stem-like cells (CSC) and enhances the efficacy of sunitinib (SUN) in the treatment of breast cancer and non-small cell lung cancer (NSCLC). To overcome the shortcomings of DA in clinical practice, the purpose of this study was to investigate the efficacy as well as the underlying mechanism of an orally available, N-arylpiperazine-containing compound C2, in the treatment of pancreatic cancer when used alone or in combination with SUN. Our results showed that C2 and SUN exerted synergistic effects on inhibiting the growth of SW1990 and PANC-1 pancreatic cancer cells. C2 significantly inhibited colony formation and migration of both cells. SW1990 xenograft and patient-derived xenograft (PDX) models were utilized for pharmacodynamic investigation in vivo. C2 alone showed little inhibition effect on tumor growth but increased the anti-tumor efficacy of SUN in both xenografts. Moreover, C2 down-regulated CSC markers (CD133 and ALDH) of both cancer cells and up-regulated the expression of dopamine receptor D1 (D1DR) in tumor. Besides, the SW1990 tumor growth was dose-dependently inhibited when the cells were pretreated with C2 before implantation. C2 increased intratumoral cAMP level, and the combination with D1DR specific antagonist SCH23390 reversed the above-mentioned effects of C2 both in vitro and in vivo, indicating the activation of D1DR may be involved in the underlying mechanism of C2 action. In summary, C2 could reduce the CSC frequency and enhance the anti-cancer effect of SUN in the treatment of pancreatic cancer, demonstrating its potential in cancer therapy.

Glucagon-like peptide-1 receptor pathway inhibits extracellular matrix production by mesangial cells through store-operated Ca2+ channel

Glomerular mesangial cell is the major source of mesangial matrix. Our previous study demonstrated that store-operated Ca2+ channel signaling suppressed extracellular matrix protein production by mesangial cells. Recent studies demonstrated that glucagon-like peptide-1 receptor (GLP-1R) pathway had renoprotective effects. However, the underlying mechanism(s) remains unclear. The present study was aimed to determine if activation of GLP-1R decreased extracellular matrix protein production by mesangial cells through upregulation of store-operated Ca2+ function. Experiments were conducted in cultured human mesangial cells. Liraglutide and exendin 9–39 were used to activate and inhibit GLP-1R, respectively. Store-operated Ca2+ function was estimated by evaluating the SOC-mediated Ca2+ entry (SOCE). We found that liraglutide treatment reduced high glucose-stimulated production of fibronectin and collagen IV. The inhibitory effects of liraglutide were not observed in the presence of exendin 9–39. Exendin-4, another GLP-1R agonist also blunted high glucose-stimulated fibronectin and collagen IV production. Treatment of human mesangial cells with liraglutide for 24 h significantly attenuated the high glucose-induced reduction of Orai1 protein. Consistently, Ca2+ imaging experiments showed that the inhibition of high glucose on SOCE was significantly attenuated by liraglutide. However, in the presence of exendin 9–39, liraglutide failed to reverse the high glucose effect. Furthermore, liraglutide effects on fibronectin and collagen IV protein abundance were significantly attenuated by GSK-7975A, a selective blocker of store-operated Ca2+. Taken together, our findings suggest that GLP-1R signaling inhibited high glucose-induced extracellular matrix protein production in mesangial cells by restoring store-operated Ca2+ function.

Impact statement

Diabetic kidney disease continues to be a major challenge to health care system in the world. There are no known therapies currently available that can cure the disease. The present study provided compelling evidence that activation of GLP-1R inhibited extracellular matrix protein production by glomerular mesangial cells. We further showed that the beneficial effect of GLP-1R was attributed to upregulation of store-operated Ca2+ channel function. Therefore, we identified a novel mechanism contributing to the renal protective effects of GLP-1R pathway. Activation of GLP-1R pathway and/or store-operated Ca2+ channel signaling in MCs could be an option for patients with diabetic kidney disease.

Deranged hepatocyte intracellular Ca2+ homeostasis and the progression of non-alcoholic fatty liver disease to hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths in men, and the sixth in women. Non-alcoholic fatty liver disease (NAFLD) is now one of the major risk factors for HCC. NAFLD, which involves the accumulation of excess lipid in cytoplasmic lipid droplets in hepatocytes, can progress to non-alcoholic steatosis, fibrosis, and HCC. Changes in intracellular Ca²⁺ constitute important signaling pathways for the regulation of lipid and carbohydrate metabolism in normal hepatocytes. Recent studies of steatotic hepatocytes have identified lipid-induced changes in intracellular Ca²⁺, and have provided evidence that altered Ca²⁺ signaling exacerbates lipid accumulation and may promote HCC. The aims of this review are to summarise current knowledge of the lipid-induced changes in hepatocyte Ca²⁺ homeostasis, to comment on the mechanisms involved, and discuss the pathways leading from altered Ca²⁺ homeostasis to enhanced lipid accumulation and the potential promotion of HCC. In steatotic hepatocytes, lipid inhibits store-operated Ca²⁺ entry and SERCA2b, and activates Ca²⁺ efflux from the endoplasmic reticulum (ER) and its transfer to mitochondria. These changes are associated with changes in Ca²⁺ concentrations in the ER (decreased), cytoplasmic space (increased) and mitochondria (likely increased). They lead to: inhibition of lipolysis, lipid autophagy, lipid oxidation, and lipid secretion; activation of lipogenesis; increased lipid; ER stress, generation of reactive oxygen species (ROS), activation of Ca²⁺/calmodulin-dependent kinases and activation of transcription factor Nrf2. These all can potentially mediate the transition of NAFLD to HCC. It is concluded that lipid-induced changes in hepatocyte Ca²⁺ homeostasis are important in the initiation and progression of HCC. Further research is desirable to better understand the cause and effect relationships, the time courses and mechanisms involved, and the potential of Ca²⁺ transporters, channels, and binding proteins as targets for pharmacological intervention.

Transcriptomic Responses of Two Ecologically Divergent Populations of Japanese Mantis Shrimp (Oratosquilla oratoria) under Thermal Stress

Simple Summary

Rising ocean temperature would change the seawater chemistry and affect the external and internal physiology of crustaceans due to their lack of certain efficient temperature regulators. In addition, the infraspecific populations of crustaceans might also have different response strategies to the rising of temperature. Therefore, we identified the transcriptomic variations to the same thermal stress between ecologically divergent populations of Oratosquilla oratoria. The aim of this study was to investigate the population-specific function genes and relevant pathways in response to thermal stress in O. oratoria. The results showed that gene-expressed variation was in a population-specific pattern, which indicated that the local environment could lead to the evolvement of changes in gene regulation, ultimately leading to adaptive divergences. Additionally, we found several genes with large pleiotropic effects in the Zhoushan population, which might indicate that the regulation mechanisms of the Zhoushan population were more efficient than those of the Qingdao population under same thermal stress. The results provided some novel insights into the local adaptive differences of the infraspecific populations of O. oratoria and other crustaceans.

Abstract

Crustaceans are generally considered more sensitive to ocean warming due to their lack of certain efficient regulators. However, the alterations in the physiology and behavior of crustaceans in response to thermal stress differ vastly even among the infraspecific populations of heterogeneous landscapes. Consequently, understanding the impact of temperature fluctuation on crustacean infraspecific populations might be essential for maintaining a sustainable persistence of populations at existing locations. In the present study, we chose the Japanese mantis shrimp (Oratosquilla oratoria) as the representative crustacean population, and conducted transcriptome analyses in two divergent O. oratoria populations (the Zhoushan and Qingdao populations) under same thermal stress (20–28 °C) to identify the population-specific expression response to thermal stress. The results showed significant differences in gene expressions, GO terms and metabolic pathways between the two populations. We hypothesized that intraspecific mutations in the same or different genes might lead to thermal adaptive divergences. Temperature increases from 20–28 °C produced significant enrichment in GO terms and altered the metabolic pathways in the Zhoushan population despite the lack of differentially expressed unigenes. Therefore, several functional genes with large pleiotropic effects may underlie the response to thermal stress in the Zhoushan population. Furthermore, the most significantly enriched biological processes of the Qingdao population were associated with the state or activity of cells and its significant enriched pathways with genetic information processing as well as immune and environmental information processing. In contrast, the differentially regulated unigenes of the Zhoushan population were primarily involved in the regulatory cellular and transcription processes and the most significant pathways found were metabolic and digestive. Consequently, the regulatory mechanisms of the Zhoushan population are probably more efficient than those of the Qingdao population under the same thermal stress.

Calcium Signaling As a Therapeutic Target for Liver Steatosis

Hepatic steatosis, the first step in nonalcoholic fatty liver disease (NAFLD), can arise from various pathophysiological conditions. While lipid metabolism in the liver is normally balanced such that there is no excessive lipid accumulation, when this homeostasis is disrupted lipid droplets (LDs) accumulate in hepatocytes resulting in cellular toxicity. The mechanisms underlying this accumulation and the subsequent hepatocellular damage are multifactorial and poorly understood, with the result that there are no currently approved treatments for NAFLD. Impaired calcium signaling has recently been identified as a cause of increased endoplasmic reticulum (ER) stress contributing to hepatic lipid accumulation. This review highlights new findings on the role of impaired Ca²⁺ signaling in the development of steatosis and discusses potential new approaches to NAFLD treatment based on these new insights.

Raman Spectroscopic Analysis of Signaling Molecules-Dopamine Receptors Interactions in Living Cells

The selective interaction of signaling compounds including neurotransmitters and drugs with the dopamine receptors (DARs) is extremely important for the treatment of neurodegenerative diseases. Here, we report a method to probe the selective interactions of signaling compounds with D1 and D2 DARs in living cells using the combined approach of theoretical calculation and surface-enhanced Raman spectroscopy (SERS). When signaling compounds such as DA, amphetamine, methamphetamine, and methylenedioxypyrovalerone interact with D1 dopamine receptors (DRD1), the intracellular cyclic adenosine monophosphate (cAMP) level is increased. However, the intracellular level of cAMP is decreased when D2 dopamine receptors (DRD2) interact with the abovementioned signaling compounds. In our experiments, we have internalized the silica-coated silver nanoparticles (AgNP@SiO₂) in living cells to adsorb biologically generated cAMP which was probed by using SERS. Besides adsorptions of cAMP, AgNP@SiO₂ has a crucial role for the enhancement of Raman cross section of the samples. We observed the characteristic SERS peaks of cAMP when DRD1-overexpressed cells interact with the signaling compounds; these peaks were not observed for other cells including DRD2-overexpressed and DRD1-DRD2-coexpressed cells. Our experimental approach is successful to probe the intracellular cAMP and characterize the selectivity of signaling compounds to different types of DARs. Furthermore, our experimental approach is highly capable for in vivo studies because it can probe intracellular cAMP using a low input power of incident laser without significant cell damage. Our experimental results and density functional theory calculations showed that 780 and 1503 cm^-1 are signature Raman peaks of cAMP. The SERS peak at 780 cm^-1 is associated with C-O, C-C, and C-N stretching and symmetric and asymmetric bending of two O-H bonds of cAMP, whereas the SERS peak at 1503 cm^-1 is contributed by the O₉-H₃ bending mode.

The Role of Neuropeptide Y in Cardiovascular Health and Disease

Neuropeptide Y (NPY) is an abundant sympathetic co-transmitter, widely found in the central and peripheral nervous systems and with diverse roles in multiple physiological processes. In the cardiovascular system it is found in neurons supplying the vasculature, cardiomyocytes and endocardium, and is involved in physiological processes including vasoconstriction, cardiac remodeling, and angiogenesis. It is increasingly also implicated in cardiovascular disease pathogenesis, including hypertension, atherosclerosis, ischemia/infarction, arrhythmia, and heart failure. This review will focus on the physiological and pathogenic role of NPY in the cardiovascular system. After summarizing the NPY receptors which predominantly mediate cardiovascular actions, along with their signaling pathways, individual disease processes will be considered. A thorough understanding of these roles may allow therapeutic targeting of NPY and its receptors.

Pharmabiotics as an Emerging Medication for Metabolic Syndrome and Its Related Diseases

Metabolic syndrome (MetS) is a cluster of metabolic risk factors associated with central obesity, hyperglycemia, insulin resistance, dyslipidemia and high blood pressure. In recent decades, because of the remarkable increase in both prevalence and severity, MetS and its related diseases such as cardiovascular diseases (CVDs), obesity, hypertension and diabetes have become the main global burden and challenge in strategic management involving prevention and treatment. However, currently, the preventions and treatments based on pharmaceutical interventions do not provide a solution for MetS and its related diseases. Recently, gut microbiota showed clear evidence of preventing and/or treating MetS, shedding light on treating MetS and its related diseases through a completely different approach. In this review, we will interpret the effects of current pharmaceutical drugs used in preventing and treating MetS and its related diseases to understand remaining issues of those interventions. We will explore the possibility of developing gut microbiota as pharmabiotics in a completely new medication option for treating MetS and its related diseases.

Exploring genetic susceptibility to obesity through genome functional pathway analysis

OBJECTIVE

Obesity has been reaching epidemic levels in recent decades, with a growing body of research identifying predisposing genetic components. To explore the relationship of genetic factors contributing to obesity, an analytical computer-based gene-profiling approach utilizing an updated list of clinically relevant and known obesity-related genes was undertaken.

METHODS

An updated list of 494 genes reportedly associated with obesity was compiled, and the GeneAnalytics profiling software was utilized to interrogate genomic databases from GeneCards® to cross-reference obesity gene sets against tissues and cells, diseases, genetic pathways, gene ontology (GO)-biological processes and GO-molecular functions, phenotypes, and compounds.

RESULTS

Obesity-related fields identified by GeneAnalytics algorithms included 8 diseases, 46 pathways, 62 biological processes, 22 molecular functions, 148 phenotypes, and 286 compounds impacting adipogenesis, signal transduction by G-protein coupled receptors, and lipid metabolism involving insulin-related genes (IGF1, INS, IRS1). GO-biological processes identified feeding behavior, cholesterol metabolic process, and glucose and cholesterol homeostasis pathways, while GO-molecular processes pertained to receptor binding, affecting glucose homeostasis, body weight, and circulating insulin and triglyceride levels.

CONCLUSIONS

The gene-profiling model suggests that pathogenesis of obesity relates to the coordination of biological responses to glucose and intracellular lipids possibly through a disruption of biochemical cascades and cellular signaling arising from affected receptors.