Perinatal metabolic inflammation in the hypothalamus impairs the development of homeostatic feeding circuitry.

Over the past few decades, there has been a global increase in childhood obesity. This rise in childhood obesity contributes to the susceptibility of impaired metabolism during both childhood and adulthood. The hypothalamus, specifically the arcuate nucleus (ARC), houses crucial neurons involved in regulating homeostatic feeding. These neurons include proopiomelanocortin (POMC) and agouti-related peptide (AGRP) secreting neurons. They play a vital role in sensing nutrients and metabolic hormones like insulin, leptin, and ghrelin. The neurogenesis of AGRP and POMC neurons completes at birth; however, axon development and synapse formation occur during the postnatal stages in rodents. Insulin, leptin, and ghrelin are the essential regulators of POMC and AGRP neurons. Maternal obesity and postnatal overfeeding or a high-fat diet (HFD) feeding cause metabolic inflammation, disrupted signaling of metabolic hormones, netrin-1, and neurogenic factors, neonatal obesity, and defective neuronal development in animal models; however, the mechanism is unclear. Within the hypothalamus and other brain areas, there exists a wide range of interconnected neuronal populations that regulate various aspects of feeding. However, this review aims to discuss how perinatal metabolic inflammation influences the development of POMC and AGRP neurons within the hypothalamus.

Targeting CTGF in Cancer: An Emerging Therapeutic Opportunity.

Despite the dramatic advances in cancer research over the decades, effective therapeutic strategies are still urgently needed. Increasing evidence indicates that connective tissue growth factor (CTGF), a multifunctional signaling modulator, promotes cancer initiation, progression, and metastasis by regulating cell proliferation, migration, invasion, drug resistance, and epithelial-mesenchymal transition (EMT). CTGF is also involved in the tumor microenvironment in most of the nodes, including angiogenesis, inflammation, and cancer-associated fibroblast (CAF) activation. In this review, we comprehensively discuss the expression of CTGF and its regulation, oncogenic role, clinical relevance, targeting strategies, and therapeutic agents. Herein, we propose that CTGF is a promising cancer therapeutic target that could potentially improve the clinical outcomes of cancer patients.

Glial Regulation of Energy Metabolism.

The major function of brain glial cells is to maintain a homeostatic milieu for neurons to work properly in response to a variety of environmental alterations. Recent studies have shown that glial cells in the hypothalamus, a brain center controlling homeostatic physiological functions, are essential for regulating energy metabolism in both physiological and pathological conditions. Astrocytes, tanycytes, and NG2-glia shuttle and/or sense key metabolic factors presented to the hypothalamus either directly, by glial metabolic enzymes, receptors, and transporters, or indirectly, by modulating the sensing ability of other types of hypothalamic cells. Astrocytes, tanycytes, and microglia are critically important in the development and maintenance of hypothalamic circuits regulating energy balance. Hypothalamic inflammation commonly associated with diet-induced obesity is manifested via hypothalamic reactive gliosis involving microglia and astrocytes, contributing to the correlated abnormal energy metabolism. Although many glial functions in energy metabolism remain to be fully elucidated, we are at the dawn of targeting glia-neuron interactions in the hypothalamus for therapeutic applications in metabolic disorders.

The antitumor natural product tanshinone IIA inhibits protein kinase C and acts synergistically with 17-AAG.

Tanshinone IIA (Tan IIA), the primary bioactive compound derived from the traditional Chinese medicine (TCM) Salvia miltiorrhiza Bunge, has been reported to possess antitumor activity. However, its antitumor mechanisms are not fully understood. To resolve the potential antitumor mechanism(s) of Tan IIA, its gene expression profiles from our database was analyzed by connectivity map (CMAP) and the CMAP-based mechanistic predictions were confirmed/validated in further studies. Specifically, Tan IIA inhibited total protein kinase C (PKC) activity and selectively suppressed the expression of cytosolic and plasma membrane PKC isoforms ζ and ε. The Ras/MAPK pathway that is closely regulated by the PKC signaling is also inhibited by Tan IIA. While Tan IIA did not inhibit heat shock protein 90 (Hsp90), it synergistically enhanced the antitumor efficacy of the Hsp90 inhibitors 17-AAG and ganetespib in human breast cancer MCF-7 cells. In addition, Tan IIA significantly inhibited PI3K/Akt/mTOR signaling, and induced both cell cycle arrest and autophagy. Collectively, these studies provide new insights into the molecular mechanisms responsible for antitumor activity of Tan IIA.

Expression and actions of GnIH and its orthologs in vertebrates: Current status and advanced knowledge.

The physiology of reproduction is very complex and is regulated by multiple factors, including a number of hypothalamic neuropeptides. In last few decades, various neuropeptides have been discovered to be involved in stimulation or inhibition of reproduction. In 2000, Tsutsui and colleagues uncovered gonadotropin-inhibitory hormone (GnIH), a neuropeptide generating inhibitory drive to the reproductive axis, in the brain of Coturnix quail. Afterward, GnIH orthologs were discovered in other vertebrates from fish to mammals including human. In these vertebrates, all the discovered GnIH and its ortholgs have LPXRFamide (X=L or Q) sequence at C-terminus. GnIH orthologs of mammals and primates are also termed as RFamide-related peptide (RFRP)-1 and -3 that too have an LPXRFamide (X=L or Q) motif at their C-terminus. GnIH and its orthologs form a member of the RFamide peptide family. GnIH signals via its canonical G protein coupled receptor 147 (GPR147). Both GnIH and GPR147 are expressed in hypothalamus and other brain regions. Besides actions through the hypothalamic GnRH and kisspeptinergic neurons, GnIH-GPR147 signaling exerts inhibitory effect on the reproductive axis via pituitary gonadotropes and directly at gonadal level. Various factors including availability and quality of food, photoperiod, temperature, social interaction, various stresses and some diseases modulate GnIH-GPR147 signaling. In this review, we have discussed expression and actions of GnIH and its orthologs in vertebrates. Special emphasis is given on the role of GnIH-GPR147 signaling pathway in the regulation of reproduction. We have also reviewed and discussed currently available literature on the participation of GnIH-GPR147 signaling pathway in the stress modulation of reproduction.

Toxins in botanical dietary supplements: blue cohosh components disrupt cellular respiration and mitochondrial membrane potential.

Certain botanical dietary supplements have been associated with idiosyncratic organ-specific toxicity. Similar toxicological events, caused by drug-induced mitochondrial dysfunction, have forced the withdrawal or U.S. FDA "black box" warnings of major pharmaceuticals. To assess the potential mitochondrial liability of botanical dietary supplements, extracts from 352 authenticated plant samples used in traditional Chinese, Ayurvedic, and Western herbal medicine were evaluated for the ability to disrupt cellular respiration. Blue cohosh (Caulophyllum thalictroides) methanol extract exhibited mitochondriotoxic activity. Used by some U.S. midwives to help induce labor, blue cohosh has been associated with perinatal stroke, acute myocardial infarction, congestive heart failure, multiple organ injury, and neonatal shock. The potential link between mitochondrial disruption and idiosyncratic herbal intoxication prompted further examination. The C. thalictroides methanol extract and three saponins, cauloside A (1), saponin PE (2), and cauloside C (3), exhibited concentration- and time-dependent mitochondriotoxic activities. Upon treatment, cell respiration rate rapidly increased and then dramatically decreased within minutes. Mechanistic studies revealed that C. thalictroides constituents impair mitochondrial function by disrupting membrane integrity. These studies provide a potential etiological link between this mitochondria-sensitive form of cytotoxicity and idiosyncratic organ damage.

Comparative study of chromatographic medium-associated mass and potential antitumor activity loss with bioactive extracts.

Natural product drug discovery programs often rely on the use of silica (Si) gel, reversed-phase media, or size-exclusion resins (e.g., RP-C18, Sephadex LH-20) for compound purification. The synthetic polymer-based sorbent Diaion HP20SS (cross-linked polystyrene matrix) is used as an alternative to prepare purified natural product libraries. To evaluate the impact of chromatographic media on the isolation of biologically active, yet chromatographically unstable natural products, Diaion HP20SS was evaluated side-by-side with normal-phase sorbents for irreversible binding of extract constituents and their effects on bioactivity. An array of chemically diverse natural product-rich extracts was selected as a test panel, and a cell-based reporter assay for hypoxia-inducible factor-1 (HIF-1) was employed to monitor potential change(s) in bioactivity. Silica gel caused significant irreversible binding of three out of 10 extracts. Curcuma longa, Saururus cernuus, and Citrus reticulata extracts showed decreased HIF-1 inhibitory activity after elution through Si gel. An additional nonpolar column wash of HP20SS with EtOAc retained considerable bioactivities of active extracts. In general, Si gel produced the greatest loss of bioactivity. However, HP20SS elution reduced significantly HIF-1 inhibitory activity of certain extracts (e.g., Asimina triloba).

Semisynthetic studies identify mitochondria poisons from botanical dietary supplements--geranyloxycoumarins from Aegle marmelos.

Bioassay-guided isolation and subsequent structure elucidation of a Bael tree Aegle marmelos lipid extract yielded two unstable acylated geranyloxycoumarin mixtures (1-2), six geranyloxycoumarins (3-8), (+)-9'-isovaleroxylariciresinol (9), and dehydromarmeline (10). In a T47D cell-based reporter assay, 1 and 2 potently inhibited hypoxia-induced HIF-1 activation (IC50 values 0.18 and 1.10 µgmL(-1), respectively). Insufficient material and chemical instability prevented full delineation of the fatty acyl side chain olefin substitution patterns in 1 and 2. Therefore, five fatty acyl geranyloxycoumarin ester derivatives (11-15) were prepared from marmin (3) and commercial fatty acyl chlorides by semisynthesis. The unsaturated C-6' linoleic acid ester derivative 14 that was structurally most similar to 1 and 2, inhibited HIF-1 activation with comparable potency (IC50 0.92 µM). The octanoyl (11) and undecanoyl (12) ester derivatives also suppressed HIF-1 activation (IC50 values 3.1 and 0.87 µM, respectively). Mechanistic studies revealed that these geranyloxycoumarin derivatives disrupt mitochondrial respiration, primarily at complex I. Thus, these compounds may inhibit HIF-1 activation by suppressing mitochondria-mediated hypoxic signaling. One surprising observation was that, while less potent, the purported cancer chemopreventive agent auraptene (8) was found to act as a mitochondrial poison that disrupts HIF-1 signaling in tumors.

Transplanted hypothalamic neurons restore leptin signaling and ameliorate obesity in db/db mice.

Evolutionarily old and conserved homeostatic systems in the brain, including the hypothalamus, are organized into nuclear structures of heterogeneous and diverse neuron populations. To investigate whether such circuits can be functionally reconstituted by synaptic integration of similarly diverse populations of neurons, we generated physically chimeric hypothalami by microtransplanting small numbers of embryonic enhanced green fluorescent protein-expressing, leptin-responsive hypothalamic cells into hypothalami of postnatal leptin receptor-deficient (db/db) mice that develop morbid obesity. Donor neurons differentiated and integrated as four distinct hypothalamic neuron subtypes, formed functional excitatory and inhibitory synapses, partially restored leptin responsiveness, and ameliorated hyperglycemia and obesity in db/db mice. These experiments serve as a proof of concept that transplanted neurons can functionally reconstitute complex neuronal circuitry in the mammalian brain.

The alternative medicine pawpaw and its acetogenin constituents suppress tumor angiogenesis via the HIF-1/VEGF pathway.

Products that contain twig extracts of pawpaw (Asimina triloba) are widely consumed anticancer alternative medicines. Pawpaw crude extract (CE) and purified acetogenins inhibited hypoxia-inducible factor-1 (HIF-1)-mediated hypoxic signaling pathways in tumor cells. In T47D cells, pawpaw CE and the acetogenins 10-hydroxyglaucanetin (1), annonacin (2), and annonacin A (3) inhibited hypoxia-induced HIF-1 activation with IC(50) values of 0.02 microg/mL, 12 nM, 13 nM, and 31 nM, respectively. This inhibition correlates with the suppression of the hypoxic induction of HIF-1 target genes VEGF and GLUT-1. The induction of secreted VEGF protein represents a key event in hypoxia-induced tumor angiogenesis. Both the extract and the purified acetogenins blocked the angiogenesis-stimulating activity of hypoxic T47D cells in vitro. Pawpaw extract and acetogenins inhibited HIF-1 activation by blocking the hypoxic induction of nuclear HIF-1alpha protein. The inhibition of HIF-1 activation was associated with the suppression of mitochondrial respiration at complex I. Thus, the inhibition of HIF-1 activation and hypoxic tumor angiogenesis constitutes a novel mechanism of action for these anticancer alternative medicines.

Epigallocatechin-3-gallate (EGCG): chemical and biomedical perspectives.

The compound (-)-epigallocatechin-3-gallate (EGCG) is the major catechin found in green tea [Camellia sinensis L. Ktze. (Theaceae)]. This polyphenolic compound and several related catechins are believed to be responsible for the health benefits associated with the consumption of green tea. The potential health benefits ascribed to green tea and EGCG include antioxidant effects, cancer chemoprevention, improving cardiovascular health, enhancing weight loss, protecting the skin from the damage caused by ionizing radiation, and others. The compound EGCG has been shown to regulate dozens of disease-specific molecular targets. Many of these molecular targets are only affected by concentrations of EGCG that are far above the levels achieved by either drinking green tea or consuming moderate doses of green tea extract-based dietary supplements. In spite of this, well-designed double-blinded controlled clinical studies have recently demonstrated the efficacy of green tea extracts and purified EGCG products in patients. Therefore, this review highlights results from what the authors believe to be some of the most clinically significant recent studies and describes current developments in the stereoselective total synthesis of EGCG.

Hypoxia-inducible factor-1 activation by (-)-epicatechin gallate: potential adverse effects of cancer chemoprevention with high-dose green tea extracts.

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that induces oxygen-regulated genes in response to reduced oxygen conditions (hypoxia). Expression of the oxygen-regulated HIF-1alpha subunit correlates positively with advanced disease stages and poor prognosis in cancer patients. Green tea catechins are believed to be responsible for the cancer chemopreventive activities of green tea. We found that (-)-epicatechin-3-gallate (ECG, 1), one of the major green tea catechins, strongly activates HIF-1 in T47D human breast carcinoma cells. Among the green tea catechins tested, 1 demonstrated the strongest HIF-1-inducing activity, while (-)-epigallocatechin-3-gallate (EGCG, 2) was significantly less active. However, 2 is relatively unstable in the in vitro system studied. Compound 1 also increases the expression of HIF-1 target genes including GLUT-1, VEGF, and CDKN1A. In T47D cells, 1 induces nuclear HIF-1alpha protein without affecting HIF-1alpha mRNA. Both the induction of HIF-1alpha protein and activation of HIF-1 by 1 can be blocked by iron and ascorbate, indicating that 1 may activate HIF-1 through the chelation of iron. These results suggest that intended cancer chemoprevention with high-dose green tea extracts may be compromised, by the ability of tea catechins to promote tumor cell survival pathways associated with HIF-1 activation.

Molecular-targeted antitumor agents: the Saururus cernuus dineolignans manassantin B and 4-O-demethylmanassantin B are potent inhibitors of hypoxia-activated HIF-1.

The transcription factor hypoxia-inducible factor-1 (HIF-1) is a key regulator of tumor cell adaptation and survival under hypoxic conditions. Selective HIF-1 inhibitors represent an important new class of potential molecular-targeted antitumor therapeutic agents. Extracts of plants and marine organisms were evaluated using a T47D human breast tumor cell-based reporter assay for HIF-1 inhibitors. Bioassay-guided fractionation of the lipid extract of Saururus cernuus resulted in the isolation of manassantin B (1) and a new compound, 4-O-demethylmanassantin B (2). The structure of 2 was determined spectroscopically. The absolute configurations of manassantin-type dineolignans have not been previously reported. Therefore, the absolute configurations of the chiral centers in each side chain were deduced from spectroscopic analysis of the Mosher MTPA ester derivatives of 1. Both 1 and 2 are among the most potent small molecule HIF-1 inhibitors discovered, to date, with IC(50) values of 3 and 30 nM, respectively. Compounds 1 and 2 selectively inhibited hypoxia-activated HIF-1 in contrast to iron chelator-activated HIF-1. Compounds 1 and 2 also inhibited hypoxic induction of the angiogenic factor VEGF. Further study revealed that 1 selectively blocked the induction of HIF-1alpha protein, the oxygen regulated HIF-1 subunit that determines HIF-1 activity.