HPLC-PDA Method for Quantification of Bioactive Compounds in Crude Extract and Fractions of Aucklandia costus Falc. and Cytotoxicity Studies against Cancer Cells.

Aucklandia costus Falc. (Synonym: Saussurea costus (Falc.) Lipsch.) is a perennial herb of the family Asteraceae. The dried rhizome is an essential herb in the traditional systems of medicine in India, China and Tibet. The important pharmacological activities reported for Aucklandia costus are anticancer, hepatoprotective, antiulcer, antimicrobial, antiparasitic, antioxidant, anti-inflammatory and anti-fatigue activities. The objective of this study was the isolation and quantification of four marker compounds in the crude extract and different fractions of A. costus and the evaluation of the anticancer activity of the crude extract and its different fractions. The four marker compounds isolated from A. costus include dehydrocostus lactone, costunolide, syringin and 5-hydroxymethyl-2-furaldehyde. These four compounds were used as standard compounds for quantification. The chromatographic data showed good resolution and excellent linearity (r2 ˃ 0.993). The validation parameters, such as inter- and intraday precision (RSD < 1.96%) and analyte recovery (97.52-110.20%; RSD < 2.00%),revealed the high sensitivity and reliability of the developed HPLC method. The compounds dehydrocostus lactone and costunolide were concentrated in the hexane fraction (222.08 and 65.07 µg/mg, respectively) and chloroform fraction (99.02 and 30.21 µg/mg, respectively), while the n-butanol fraction is a rich source of syringin (37.91 µg/mg) and 5-hydroxymethyl-2-furaldehyde (7.94 µg/mg). Further, the SRB assay was performed for the evaluation of anticancer activity using lung, colon, breast and prostate cancer cell lines. The hexane and chloroform fractions show excellent IC50 values of 3.37 ± 0.14 and 7.527 ± 0.18 µg/mL, respectively, against the prostate cancer cell line (PC-3).

DNMT1 represses p53 to maintain progenitor cell survival during pancreatic organogenesis.

In the developing pancreas, self-renewal of progenitors and patterning of cell fates are coordinated to ensure the correct size and cellular makeup of the organ. How this coordination is achieved, however, is not clear. We report that deletion of DNA methyltransferase 1 (Dnmt1) in pancreatic progenitors results in agenesis of the pancreas due to apoptosis of progenitor cells. We show that DNMT1 is bound to the p53 regulatory region and that loss of Dnmt1 results in derepression of the p53 locus. Haploinsufficiency of p53 rescues progenitor cell survival and cellular makeup of the Dnmt1-deleted pancreas.

Nkx2.2 repressor complex regulates islet ß-cell specification and prevents ß-to-α-cell reprogramming.

Regulation of cell differentiation programs requires complex interactions between transcriptional and epigenetic networks. Elucidating the principal molecular events responsible for the establishment and maintenance of cell fate identities will provide important insights into how cell lineages are specified and maintained and will improve our ability to recapitulate cell differentiation events in vitro. In this study, we demonstrate that Nkx2.2 is part of a large repression complex in pancreatic ß cells that includes DNMT3a, Grg3, and HDAC1. Mutation of the endogenous Nkx2.2 tinman (TN) domain in mice abolishes the interaction between Nkx2.2 and Grg3 and disrupts ß-cell specification. Furthermore, we demonstrate that Nkx2.2 preferentially recruits Grg3 and HDAC1 to the methylated Aristaless homeobox gene (Arx) promoter in ß cells. The Nkx2.2 TN mutation results in ectopic expression of Arx in ß cells, causing ß-to-α-cell transdifferentiation. A corresponding ß-cell-specific deletion of DNMT3a is also sufficient to cause Arx-dependent ß-to-α-cell reprogramming. Notably, subsequent removal of Arx in the ß cells of Nkx2.2(TNmut/TNmut) mutant mice reverts the ß-to-α-cell conversion, indicating that the repressor activities of Nkx2.2 on the methylated Arx promoter in ß cells are the primary regulatory events required for maintaining ß-cell identity.

BET Proteins Are Required for Transcriptional Activation of the Senescent Islet Cell Secretome in Type 1 Diabetes.

Type 1 diabetes (T1D) results from the progressive loss of pancreatic beta cells as a result of autoimmune destruction. We recently reported that during the natural history of T1D in humans and the female nonobese diabetic (NOD) mouse model, beta cells acquire a senescence-associated secretory phenotype (SASP) that is a major driver of disease onset and progression, but the mechanisms that activate SASP in beta cells were not explored. Here, we show that the SASP in islet cells is transcriptionally controlled by Bromodomain ExtraTerminal (BET) proteins, including Bromodomain containing protein 4 (BRD4). A chromatin analysis of key beta cell SASP genes in NOD islets revealed binding of BRD4 at active regulatory regions. BET protein inhibition in NOD islets diminished not only the transcriptional activation and secretion of SASP factors, but also the non-cell autonomous activity. BET protein inhibition also decreased the extent of SASP induction in human islets exposed to DNA damage. The BET protein inhibitor iBET-762 prevented diabetes in NOD mice and also attenuated SASP in islet cells in vivo. Taken together, our findings support a crucial role for BET proteins in the activation of the SASP transcriptional program in islet cells. These studies suggest avenues for preventing T1D by transcriptional inhibition of SASP.

The histone demethylase Jmjd3 sequentially associates with the transcription factors Tbx3 and Eomes to drive endoderm differentiation.

Stem cell differentiation depends on transcriptional activation driven by lineage-specific regulators as well as changes in chromatin organization. However, the coordination of these events is poorly understood. Here, we show that T-box proteins team up with chromatin modifying enzymes to drive the expression of the key lineage regulator, Eomes during endodermal differentiation of embryonic stem (ES) cells. The Eomes locus is maintained in a transcriptionally poised configuration in ES cells. During early differentiation steps, the ES cell factor Tbx3 associates with the histone demethylase Jmjd3 at the enhancer element of the Eomes locus to allow enhancer-promoter interactions. This spatial reorganization of the chromatin primes the cells to respond to Activin signalling, which promotes the binding of Jmjd3 and Eomes to its own bivalent promoter region to further stimulate Eomes expression in a positive feedback loop. In addition, Eomes activates a transcriptional network of core regulators of endodermal differentiation. Our results demonstrate that Jmjd3 sequentially associates with two T-box factors, Tbx3 and Eomes to drive stem cell differentiation towards the definitive endoderm lineage.

Bmi-1 regulates the Ink4a/Arf locus to control pancreatic beta-cell proliferation.

The molecular mechanisms that regulate the age-induced increase of p16(INK4a) expression associated with decreased beta-cell proliferation and regeneration are not well understood. We report that in aged islets, derepression of the Ink4a/Arf locus is associated with decreased Bmi-1 binding, loss of H2A ubiquitylation, increased MLL1 recruitment, and a concomitant increase in H3K4 trimethylation. During beta-cell regeneration these histone modifications are reversed resulting in reduced p16(INK4a) expression and increased proliferation. We suggest that PcG and TrxG proteins impart a combinatorial code of histone modifications on the Ink4a/Arf locus to control beta-cell proliferation during aging and regeneration.

Formation and regeneration of the endocrine pancreas.

The elaboration of the pancreas from epithelial buds to the intricate organ requires complex patterning information that controls fundamental cellular processes such as differentiation and proliferation of pancreatic progenitor cells. During pancreatic organogenesis, endocrine cells are generated from a population of pancreatic progenitor cells. The progenitor cells during the early development simultaneously receive multiple signals, some mitogenic and some inducing differentiation. These extrinsic signals are interpreted through an intrinsic mechanism that either commits the progenitor cell to the mitotic cell cycle or leads to exit from the cell cycle in order to differentiate. The endocrine cells that differentiate from progenitor cells are postmitotic, and direct lineage tracing analyses indicate that a population of progenitor cells persists throughout embryogenesis to allow the differentiation of new endocrine cells. At the end of embryogenesis an early postnatal period is characterized by high rates of beta cell proliferation leading to massive increases in beta cell mass. The beta cell mass expansion considerably slows down in adult animals, though variations in insulin demand due to physiological and pathological states such as pregnancy and obesity can lead to adaptive changes in the beta cells that include hyperplasia, hypertrophy, and increased insulin synthesis and secretion. Deciphering the mechanisms that regulate the plasticity of beta cell mass can be an important step in developing effective strategies to treat diabetes.

Inflammatory ß-Cell Stress and Immune Surveillance in Type 1 Diabetes.

Recent years have seen increased recognition for the role of ß-cell stress as a contributing factor to the autoimmune destruction process that ultimately results in symptomatic type 1 diabetes (T1D). Preclinical studies have discovered a variety of stress responses in the ß-cell that occur at presymptomatic stages and contribute to disease progression, but unifying explanations of how these mechanisms operate to promote disease progression remain incomplete. We propose that stressed ß-cells transition into ß-cells expressing inflammatory molecules that provoke an immune response to restore homeostasis by coordinating islet repair and the removal of stressed cells. However, when immune surveillance fails, stressed ß-cells accumulate and contribute to autoimmunity. Therapies directed toward stressed ß-cells to either curb their inflammatory signaling or to eliminate them (essentially doing the job of the failed immune surveillance) are moving from animal models into the clinic with promising initial results, although the understanding of how the immune response is coordinated by stressed ß-cells is not clear. In this article, we discuss ß-cell stress responses implicated in T1D pathogenesis based on evidence from humans and highlight existing knowledge gaps in their mechanisms. Future work in this field is poised to target T1D by simultaneously targeting stressed ß-cells and the failed immune response to halt the progression of autoimmunity and prevent ß-cell destruction.

Biotransformation of eugenol by an endophytic fungus Daldinia sp. IIIMF4010 isolated from Rosmarinus officinalis.

Natural value-added compounds produced from biological sources have attained immense significance in medicinal, food, flavourings, and agrochemical industries. Further, biotransformation is a powerful tool used to produce value-added compounds cost-effectively and selectively. In the present study, biotransformation of eugenol using an endophytic fungus Daldinia sp. IIIMF4010 isolated from the fresh leaves of the plant Rosmarinus officinalis leads to the production of two known value-added compounds. The biotransformation reaction of eugenol (50 mM) resulted in the production of eugenol-ß-D-glucopyranoside (6.2%) and vanillin (21.8%). These biotransformed products were further characterized by liquid chromatography-mass spectroscopy (LC-MS) and nuclear magnetic resonance (NMR).

Apoptotic Potential and Antitumor Efficacy of Trilliumoside A: A New Steroidal Saponin Isolated from Rhizomes of Trillium govanianum.

Natural product-derived molecules exhibit potential as anticancer agents. Trilliumoside A, a new steroidal saponin, was obtained from rhizomes of Trillium govanianum, and its anticancer activity was investigated in the presented study. Trilliumoside A was investigated in a panel of cell lines, and it exhibited promising cytotoxic activity on the A549 cells (human lung cancer cells) with an IC50 of 1.83 µM. The mechanism of cell death induced by Trilliumoside A in A549 cells and its anticancer potential in murine tumor models (EAC and EAT) were presented in the current research. Trilliumoside A was found to induce apoptosis in A549 cells by increasing the expression of various apoptotic proteins, such as Bax, Puma, cytochrome C, cleaved PARP, and cleaved caspase 3. Additionally, Trilliumoside A regulates the expression of p53, CDK2, and Cyclin A by decreasing the mitochondrial membrane potential, elevating reactive oxygen species, and stopping the growth of A549 cells in the synthesis phase (S) of the cell cycle. Trilliumoside A showed a considerable reduction in the tumor volume, the amount of ascitic fluid, and the total cell number without affecting the body weight of animals. Our results demonstrate that Trilliumoside A inhibits the proliferation of human lung cancer cells by inducing DNA damage, arresting the cell cycle, and activating the mitochondrial signaling pathway. The study demonstrated the potential of Trilliumoside A as a potential anticancer agent.

Costunosides A-C: cytotoxic sesquiterpene lactones from the rhizomes of Aucklandia costus Falc.

Three new eudesmane type rare sesquiterpene lactone galactosides, costunosides A-C (1-3) were isolated from the rhizomes of Aucklandia costus along with ten known compounds (4-13). Costunosides A-C (1-3) are the first example of naturally eudesmane glycosides containing a ß-galactopyranoside moiety. The structure and relative configurations of these compounds were established by comprehensive analysis of MS and, in particular 1D/2D NMR spectroscopic data. The isolated compounds were tested against a panel of human cancer cell lines, where compounds 3, 6 and 7 have shown promising cytotoxic activity against PC-3, HCT-116 and A549 cell lines with IC50 values in the range of 3.4 µM to 9.3 µM, respectively. Costunosides A-C (1-3) were also screened for inhibition assay of acetyl-cholinesterase (AChE), and butyrylcholinesterase (BChE) and found inactive at a concentration of 10 µM.

In-vitro anti-sickling potential of baicalin and naringenin isolated from Oroxylum indicum and Citrus aurantium on human sickle red blood cells.

Sickle cell disease (SCD) is a rare inherited disorder in which red blood cells (RBCs) under oxidative stress have altered sickle shape resulting in clinical complications. In this study, a library of pure natural products were screened to see their effectiveness in preventing sickling induced in blood samples of SCA patients, ex-vivo. The results indicated that baicalin (1) and naringenin (2), reduced sickling by 46.03 and 37.48 percent, respectively, compared to positive control, 4-hydroxybenzoic acid (4-HBA), which inhibited RBC sickling by 56.87 percent. As a result of this screening, two compounds, baicalin (1) and naringenin (2), have been identified as potent sickling inhibitors. Study has clearly shown promising role of flavonoids for the management of SCD crisis for that not effective therapy is available. These phytochemicals or plant extracts can be explored further as an alternative anti-sickling remedy, owing to their high efficacy in the management of SCD crisis.

Trilliumosides K and L, two novel steroidal saponins from rhizomes of Trillium govanianum, as potent anti-cancer agents targeting apoptosis in the A-549 cancer cell line.

Two novel steroidal saponins, trilliumosides K (1) and L (2), were isolated from the rhizomes of Trillium govanianum led by bioactivity-guided phytochemical investigation along with seven known compounds: govanoside D (3), protodioscin (4), borassoside E (5), 20-hydroxyecdysone (6), 5,20-hydroxyecdysone (7), govanic acid (8), and diosgenin (9). The structure of novel compounds 1-2 was established using analysis of spectroscopic data including 1D and 2D nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HR-ESI-MS) data. All isolated compounds were evaluated for in vitro cytotoxic activity against a panel of human cancer cell lines. Compound 1 showed significant cytotoxic activity against the A-549 (Lung) and SW-620 (Colon) cancer cell lines with IC50 values of 1.83 and 1.85 µM, respectively whereas the IC50 value of Compound 2 against the A-549 cell line was found to be 1.79 µM. Among the previously known compounds 3, 5, and 9, the cytotoxic IC50 values were found to be in the range of 5-10 µM. Comprehensive anti-cancer investigation revealed that Compound 2 inhibited in vitro migration and colony-forming capability in the A-549 cell line. Additionally, the mechanistic analysis of Compound 2 on the A-549 cell line indicated distinctive alterations in nuclear morphology, increased reactive oxygen species (ROS) production, and decreased levels of mitochondrial membrane potential (MMP). By upregulating the pro-apoptotic protein BAX and downregulating the anti-apoptotic protein BCL-2, the aforementioned actions eventually cause apoptosis, a crucial hallmark in cancer research, which activates Caspase-3. To the best of our knowledge, this study reports the first mechanistic anti-cancer evaluation of the compounds isolated from the rhizomes of T. govanianum with remarkable cytotoxic activity in the desired micromolar range.

Comparative morpho-anatomical standardization and chemical profiling of root drugs for distinction of fourteen species of family Apocynaceae.

BACKGROUND: The root drugs of the family Apocynaceae are medicinally important and used in Indian Systems of Medicine (ISM). There is often a problem of misidentification and adulteration of genuine samples with other samples in the market trade. Keeping in view the adulteration problem of raw drug material, comparative macroscopic and microscopic (qualitative and quantitative) characterisation and chemical analysis (TLC and LC-MS profiling) of a total of 14 economically important root drugs of family Apocynaceae were done for practical and rapid identification. A total of 33 qualitative botanical characteristics of root samples were subjected to Principal Component Analysis (PCA) and Cluster analysis to identify taxonomically significant characteristics in the distinction of root drug samples at the species level. RESULTS: Comparative qualitative and quantitative data on morphological, macroscopic, and microscopic characters were generated for the studied 14 species. Despite the similarity in some root characters, a combined study involving the surface, anatomical, and powder features helped distinguish root samples at the species level. The relative relationship between selected species was represented as clustering or grouping in the dendrogram. PCA analysis determined significant characters leading to species grouping and identification. Results showed that clustering of xylem vessels in cross-section, pore size, and distribution in the cut root, the shape of starch grains, the thickness of cork zone were among the most notable characters in species distinction. Chemical profiling revealed unique fingerprints and content of chemical compounds, which were significant in identification of root drug samples. CONCLUSIONS: The comparative botanical standards and chemical profiles developed in the present study can be used as future reference standards for the quick, easy, and correct identification of root drug samples to be used in the herbal drug industry. Further, the identified significant microscopic characters have the potential for taxonomic studies in species delimitation.

Heterorhabditis and Photorhabdus Symbiosis: A Natural Mine of Bioactive Compounds.

Phylum Nematoda is of great economic importance. It has been a focused area for various research activities in distinct domains across the globe. Among nematodes, there is a group called entomopathogenic nematodes, which has two families that live in symbiotic association with bacteria of genus Xenorhabdus and Photorhabdus, respectively. With the passing years, researchers have isolated a wide array of bioactive compounds from these symbiotically associated nematodes. In this article, we are encapsulating bioactive compounds isolated from members of the family Heterorhabditidae inhabiting Photorhabdus in its gut. Isolated bioactive compounds have shown a wide range of biological activity against deadly pathogens to both plants as well as animals. Some compounds exhibit lethal effects against fungi, bacteria, protozoan, insects, cancerous cell lines, neuroinflammation, etc., with great potency. The main aim of this article is to collect and analyze the importance of nematode and its associated bacteria, isolated secondary metabolites, and their biomedical potential, which can serve as potential leads for further drug discovery.

The Transcription Factor YY1 Is Essential for Normal DNA Repair and Cell Cycle in Human and Mouse ß-Cells.

Identifying the mechanisms behind the ß-cell adaptation to failure is important to develop strategies to manage type 2 diabetes (T2D). Using db/db mice at early stages of the disease process, we took advantage of unbiased RNA sequencing to identify genes/pathways regulated by insulin resistance in ß-cells. We demonstrate herein that islets from 4-week-old nonobese and nondiabetic leptin receptor-deficient db/db mice exhibited downregulation of several genes involved in cell cycle regulation and DNA repair. We identified the transcription factor Yin Yang 1 (YY1) as a common gene between both pathways. The expression of YY1 and its targeted genes was decreased in the db/db islets. We confirmed the reduction in YY1 expression in ß-cells from diabetic db/db mice, mice fed a high-fat diet (HFD), and individuals with T2D. Chromatin immunoprecipitation sequencing profiling in EndoC-ßH1 cells, a human pancreatic ß-cell line, indicated that YY1 binding regions regulate cell cycle control and DNA damage recognition and repair. We then generated mouse models with constitutive and inducible YY1 deficiency in ß-cells. YY1-deficient mice developed diabetes early in life due to ß-cell loss. ß-Cells from these mice exhibited higher DNA damage, cell cycle arrest, and cell death as well as decreased maturation markers. Tamoxifen-induced YY1 deficiency in mature ß-cells impaired ß-cell function and induced DNA damage. In summary, we identified YY1 as a critical factor for ß-cell DNA repair and cell cycle progression.

Uncovering immune and senescent cell interactions in disease.

In this backstory, Anil Bhushan explains how recent work from his group investigating the immune-mediated clearance of senescent cells may offer a unique route to the development of senolytic therapies. These findings appeared in the May 2021 issue of Med (https://www.cell.com/med/fulltext/S2666-6340(21)00163-X).

Invariant Natural Killer T cells coordinate removal of senescent cells.

BACKGROUND: The failure of immune surveillance to remove senescent cells drive age-related diseases. Here, we target an endogenous immune surveillance mechanism that can promote elimination of senescent cells and reverse disease progression. METHODS: We identify a class of lipid-activated T cells, invariant natural killer T cells (iNKTs) are involved in the removal of pathologic senescent cells. We use two disease models in which senescent cells accumulate to test whether activation of iNKT cells was sufficient to eliminate senescent cells in vivo. FINDINGS: Senescent preadipocytes accumulate in white adipose tissue of chronic high-fat diet (HFD) fed mice, and activation of iNKT cells with the prototypical glycolipid antigen alpha-galactosylceramide (αGalCer) led to a reduction of these cells with improved glucose control. Similarly, senescent cells accumulate within the lungs of mice injured by inhalational bleomycin, and αGalCer-induced activation of iNKT cells greatly limited this accumulation, decreased the lung fibrosis and improved survival. Furthermore, co-culture experiments showed that the preferential cytotoxic activity of iNKT cells to senescent cells is conserved in human cells. CONCLUSIONS: These results uncover a senolytic capacity of tissue-resident iNKT cells and pave the way for anti-senescence therapies that target these cells and their mechanism of activation.

Inconsistent formation and nonfunction of insulin-positive cells from pancreatic endoderm derived from human embryonic stem cells in athymic nude rats.

Embryonic stem cell therapy has been proposed as a therapeutic strategy to restore ß-cell mass and function in T1DM. Recently, a group from Novocell (now ViaCyte) reported successful development of glucose-responsive islet-like structures after implantation of pancreatic endoderm (PE) derived from human embryonic stem cells (hESC) into immune-deficient mice. Our objective was to determine whether implantation of hESC-derived pancreatic endoderm from Novocell into athymic nude rats results in development of viable glucose-responsive pancreatic endocrine tissue. Athymic nude rats were implanted with PE derived from hESC either via implantation into the epididymal fat pads or by subcutaneous implantation into TheraCyte encapsulation devices for 20 wk. Blood glucose, weight, and human insulin/C-peptide secretion were monitored by weekly blood draws. Graft ß-cell function was assessed by a glucose tolerance test, and graft morphology was assessed by immunohistochemistry and immunofluorescence. At 20 wk postimplantation, epididymal fat-implanted PE progressed to develop islet-like structures in 50% of implants, with a mean ß-cell fractional area of 0.8 ± 0.3%. Human C-peptide and insulin were detectable, but at very low levels (C-peptide = 50 ± 26 pmol/l and insulin = 15 ± 7 pmol/l); however, there was no increase in human C-peptide/insulin levels after glucose challenge. There was no development of viable pancreatic tissue or meaningful secretory function when human PE was implanted in the TheraCyte encapsulation devices. These data confirm that islet-like structures develop from hESC differentiated to PE by the protocol developed by NovoCell. However, the extent of endocrine cell formation and secretory function is not yet sufficient to be clinically relevant.

Essential role of Skp2-mediated p27 degradation in growth and adaptive expansion of pancreatic beta cells.

Diabetes results from an inadequate mass of functional beta cells, due to either beta cell loss caused by immune assault or the lack of compensation to overcome insulin resistance. Elucidating the mechanisms that regulate beta cell mass has important ramifications for fostering beta cell regeneration and the treatment of diabetes. We report here that Skp2, a substrate recognition component of Skp1-Cul1-F-box (SCF) ubiquitin ligase, played an essential and specific role in regulating the cellular abundance of p27 and was a critical determinant of beta cell proliferation. In Skp2(-/-) mice, accumulation of p27 resulted in enlarged polyploid beta cells as a result of endoreduplication replacing proliferation. Despite beta cell hypertrophy, Skp2(-/-) mice exhibited diminished beta cell mass, hypoinsulinemia, and glucose intolerance. Increased insulin resistance resulting from diet-induced obesity caused Skp2(-/-) mice to become overtly diabetic, because beta cell growth in the absence of cell division was insufficient to compensate for increased metabolic demand. These results indicate that the Skp2-mediated degradation pathway regulating the cellular degradation of p27 is essential for establishing beta cell mass and to respond to increased metabolic demand associated with insulin resistance.