Alzheimer's disease (AD) and type 2 diabetes mellitus (DM) are more prevalent with ageing and cause a substantial global socio-economic burden. The biology of these two conditions is well elaborated, but whether AD and type 2 DM arise from coincidental roots in ageing or are linked by pathophysiological mechanisms remains unclear. Research findings involving animal models have identified mechanisms shared by both AD and type 2 DM. Deposition of β-amyloid peptides and formation of intracellular neurofibrillary tangles are pathological hallmarks of AD. Type 2 DM, on the other hand, is a metabolic disorder characterised by hyperglycaemia and insulin resistance. Several studies show that improving type 2 DM can delay or prevent the development of AD, and hence, prevention and control of type 2 DM may reduce the risk of AD later in life. Alpha-glucosidase is an enzyme that is commonly associated with hyperglycaemia in type 2 DM. However, it is uncertain if this enzyme may play a role in the progression of AD. This review explores the experimental evidence that depicts the relationship between dysregulation of glucose metabolism and AD. We also delineate the links between alpha-glucosidase and AD and the potential role of alpha-glucosidase inhibitors in treating AD.
Lysosome is a primary degradative organelle and is crucial in cellular homeostasis. A reduction in its function due to ageing has been associated with the development of Alzheimer's disease (AD), a common neurodegenerative disorder characterised by the deposition of neurotoxic amyloid plaque in the brain and cerebral vessel walls. The breakdown of the blood-brain barrier (BBB) plays a vital role in the pathogenesis of AD. However, the impact of lysosomal dysfunction on brain endothelial cells, the key component of the BBB, in the disease progression is yet to be fully understood. In this study, human brain endothelial cells (HBEC-5i) were exposed to a lysosomotropic compound, chloroquine (CQ) for 24 h. Cell viability was assessed with the 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay to determine the inhibitory concentration (IC) at IC10 (17.5 µM), IC25 (70.5 µM), and IC50 (125 µM). The morphological changes observed include vacuoles arrested in the cytosols and cell shrinkage that were more prominent at IC25 and IC50. Lysosomal dysfunction was evaluated by measuring the lysosomal-associated membrane protein-1 (LAMP-1) and microtubule-associated protein light chain 3-II (LC3-II) using the capillary-based immunoassay. LC3-II was significantly increased at IC25 and IC50 (p
Dengue infections pose a critical threat to public health worldwide. Since there are no clinically approved antiviral drugs to treat dengue infections caused by the four dengue virus (DENV) serotypes, there is an urgent need to develop effective antivirals. Peptides are promising antiviral candidates due to their specificity and non-toxic properties. The DENV envelope (E) protein was selected for the design of antiviral peptides due to its importance in receptor binding and viral fusion to the host cell membrane. Twelve novel peptides were designed to mimic regions containing critical amino acid residues of the DENV E protein required for interaction with the host. A total of four peptides were identified to exhibit potent inhibitory effects against at least three or all four DENV serotypes. Peptide 3 demonstrated all three modes of action: cell protection and inhibition of post-infection against all four DENV serotypes, whereas direct virus-inactivating effects were only observed against DENV-2, 3, and 4. Peptide 4 showed good direct virus-inactivating effects against DENV-2 (74.26%) as well as good inhibitions of DENV-1 (80.37%) and DENV-4 (72.22%) during the post-infection stage. Peptide 5 exhibited direct virus-inactivating effects against all four DENV serotypes, albeit at lower inhibition levels against DENV-1 and DENV-3. It also exhibited highly significant inhibition of DENV-4 (89.31%) during post-infection. Truncated peptide 5F which was derived from peptide 5 showed more significant inhibition of DENV-4 (91.58%) during post-infection and good direct virus-inactivating effects against DENV-2 (77.55%) at a lower concentration of 100 μM. Peptide 3 could be considered as the best antiviral candidate for pre- and post-infection treatments of DENV infections in regions with four circulating dengue serotypes. However, if the most predominant dengue serotype for a particular region could be identified, peptides with significantly high antiviral activities against that particular dengue serotype could serve as more suitable antiviral candidates. Thus, peptide 5F serves as a more suitable antiviral candidate for post-infection treatment against DENV-4.
Dengue presents a major public health concern in over 100 countries due to the absence of an effective vaccine and antiviral therapy against all four dengue virus (DENV) serotypes. Several antiviral peptides were previously reported to inhibit at least three or all four DENV serotypes. Chemical modifications such as d-amino acid substitutions, polyethylene glycol (PEG)ylation, and cyclization could be applied to peptides to improve their biological activities and stability in serum. The PEGylated peptide 3 (PEG-P3) was identified to be the most promising antiviral candidate as it demonstrated good inhibitory effects against all four DENV serotypes during the pre- and post-infection stages, Based on the RP-HPLC and LC/MS analysis, peptide 4 was identified to be more stable in human serum than peptide 3, with 78.9 % and 41.6 % of the peptides remaining after 72 h of incubation in human serum, respectively. Both peptides were also able to retain their antiviral activities against specific DENV serotypes after 72 h incubation in human serum. PEG-P3 was found to be more stable than the unmodified peptide 3 with 89.4 % of PEG-P3 remaining in the human serum after 72 h of incubation. PEG-P3 was able to retain its inhibitory effects against DENV-1 to 4 after 72 h of incubation in human serum. This study provided insights into the antiviral activities and stabilities of the unmodified and chemically modified peptides in human serum.
Macromolecular protein and peptide therapeutics have been proven to be effective in treating critical human diseases precisely. Thanks to biotechnological advancement, a huge number of proteins and peptide therapeutics were made their way to pharmaceutical market in past few decades. However, one of the biggest challenges to be addressed for protein therapeutics during clinical application is their fast degradation in serum and quick elimination owing to enzymatic degradation, renal clearance, liver metabolism and immunogenicity, attributing to the short half-lives. Size and hydrophobicity of protein molecules make them prone to kidney filtration and liver metabolism. On the other hand, proteasomes responsible for protein destruction possess the capability of specifically recognizing almost all kinds of foreign proteins while avoiding any unwanted destruction of cellular components. At present almost all protein-based drug formulations available in market are administered intravenously (IV) or subcutaneously (SC) with high dosing at frequent interval, eventually creating dose-fluctuation-related complications and reducing patient compliance vastly. Therefore, artificially increasing the therapeutic half-life of a protein by attaching to it a molecule that increases the overall size (eg, PEG) or helps with receptor mediated recycling (eg, albumin), or manipulating amino acid chain in a way that makes it more prone towards aggregate formation, are some of the revolutionary approaches to avoid the fast degradation in vivo. Half-life extension technologies that are capable of dramatically enhancing half-lives of proteins in circulation (2-100 folds) and thus improving their overall pharmacokinetic (PK) parameters have been successfully applied on a wide range of protein therapeutics from hormones and enzymes, growth factor, clotting factor to interferon. The focus of the review is to assess the technological advancements made so far in enhancing circulatory half-lives and improving therapeutic potency of proteins.
Analisis geokimia menggunakan kaedah ICP-MS menunjukkan taburan geokimia unsur di kawasan kajian dipengaruhi
oleh dua asalan sedimen berbeza iaitu daripada marin dan daratan. Unsur Ca dan Mg dikenal pasti sebagai unsur
marin, manakala unsur Al, Fe, Mn, Na, Cu, Cr, Zn dan Ni dikenal pasti sebagai unsur daratan. Unsur Ca dan Mg dikenal
pasti terhasil daripada proses penyahkapuran rangka dan hidupan marin seperti cengkerang moluska dan foraminifera.
Unsur benua berasal daripada granit dari Gunung Korbu dan Gunung Stong yang disaliri oleh Sungai Nenggiri dan
Sungai Galas, serta batuan argilit arenit yang berasal dari bahagian selatan dan tenggara Negeri Kelantan dari
Gunung Cintawangsa dan Gunung Stong dan disaliri oleh Sungai Lebir dan Sungai Galas. Unsur daripada batuan
induk membebaskan unsur kimia semasa luluhawa kimia dan telah dijerap oleh cas-cas negatif pada permukaan sedimen
halus seperti lempung dan lodak sebelum dimendapkan bersama di dalam kawasan kajian.
Chemical transformations of Amadori compounds are responsible for the formation of aroma volatiles at the end of the Maillard reaction cascade, which in turn contributes to unique organoleptic characteristics of chocolate. A large amount of short peptides reported in fermented cocoa suggests the existence of a much larger variety of these flavor precursors than previously suspected. An HPLC-MS-MS study was performed on dried Malaysian cocoa beans to identify novel Amadori and Heyns compounds. In total, 34 species were found, including 26 previously unknown derived from di- and tripeptides. We illustrate how the structures were elucidated via tandem MS experiments, as well as present a comparative study on their relative quantities in samples coming from 11 countries of origin. There were significant differences between them, and discrimination was possible by principal component analysis based on Amadori content alone. However, the PCA separation could be a result of various post-harvest practices exerted among said countries.
Jackfruit is a sweet tropical fruit with very pleasant aroma, and the ripe seeds are edible. In this study, jackfruit seed proteins were isolated and subjected to trypsin digestion. The resultant protein hydrolysate was then subjected to antioxidant assay-guided purification, using centrifugal filtration, C18 reverse-phase and strong cation exchange (SCX) fractionations. The purified SCX fraction was further analyzed by de novo peptide sequencing, and two peptide sequences were identified and synthesized. Peptide JFS-2 (VGPWQK) was detected with antioxidant potential, with EC50 value comparable to that of commercial GSH antioxidant peptide. Additionally, the identified peptides were tested with protein protection potential, in an albumin protein denaturation inhibitory assay. Concurrently, we also investigated the pH, temperature, and gastrointestinal-digestion stability profiles for the identified peptide. With further research efforts, the identified peptides could potentially be developed into preservative agent for protein-rich food systems or as health-promoting diet supplements.
A Montana soil actinomycete, Streptomyces anulatus, produced (1 x 10(-2)% yield) a new cancer cell growth inhibitory cyclooctadepsipeptide named montanastatin (1) accompanied by the potent anticancer antibiotic valinomycin (2) in very high (5.1%) yields. Valinomycin but not montanastatin inhibited growth of a number of pathogenic bacteria and fungi. Interpretation of high-field (500 MHz) NMR and high-resolution FAB mass spectral data allowed assignment of the structure cyclo-(D-Val-L-Lac-L-Val-D-Hiv) to montanastatin. Valinomycin (2) was also isolated from actinomycetes cultured from a tree branch and animal feces collected in Malaysia. Streptomyces exfoliatus, isolated from the tree branch, was found to contain valinomycin in 1.6% yield, while the fecal isolate, S. anulatus, gave valinomycin in 0.9% yield.
Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting about 0.24 % of the world population. Protein arginine deiminase type 4 (PAD4) is believed to be responsible for the occurrence of RA by catalyzing citrullination of proteins. The citrullinated proteins act as autoantigens by stimulating an immune response. Citrullinated α-enolase has been identified as one of the autoantigens for RA. Hence, α-enolase serves as a suitable template for design of potential peptide inhibitors against PAD4. The binding affinity of α-enolase-derived peptides and PAD4 was virtually determined using PatchDock and HADDOCK docking programs. Synthesis of the designed peptides was performed using a solid phase peptide synthesis method. The inhibitory potential of each peptide was determined experimentally by PAD4 inhibition assay and IC50 measurement. PAD4 assay data show that the N-P2 peptide is the most favourable substrate among all peptides. Further modification of N-P2 by changing the Arg residue to canavanine [P2 (Cav)] rendered it an inhibitor against PAD4 by reducing the PAD4 activity to 35 % with IC50 1.39 mM. We conclude that P2 (Cav) is a potential inhibitor against PAD4 and can serve as a starting point for the development of even more potent inhibitors.
Hyperglycemia, a distinguishing feature of diabetes mellitus that might cause a diabetic foot ulcer (DFU), is an endocrine disorder that affects an extremely high percentage of people. Having a comprehensive understanding of the molecular mechanisms underlying the pathophysiology of diabetic wound healing can help researchers and developers design effective therapeutic strategies to treat the wound healing process in diabetes patients. Using nanoscaffolds and nanotherapeutics with dimensions ranging from 1 to 100 nm represents a state-of-the-art and viable therapeutic strategy for accelerating the wound healing process in diabetic patients, particularly those with DFU. Nanoparticles can interact with biological constituents and infiltrate wound sites owing to their reduced diameter and enhanced surface area. Furthermore, it is noteworthy that they promote the processes of vascularization, cellular proliferation, cell signaling, cell-to-cell interactions, and the formation of biomolecules that are essential for effective wound healing. Nanomaterials possess the ability to effectively transport and deliver various pharmacological agents, such as nucleic acids, growth factors, antioxidants, and antibiotics, to specific tissues, where they can be continuously released and affect the wound healing process in DFU. The present article elucidates the ongoing endeavors in the field of nanoparticle-mediated therapies for the management of DFU.
Matched MeSH terms: Intercellular Signaling Peptides and Proteins
Alzheimer's disease (AD) is the most common neurodegenerative condition in civilizations worldwide. The distinctive occurrence of amyloid-beta (Aβ) accumulation into insoluble fibrils is part of the disease pathophysiology with Aβ42 being the most toxic and aggressive Aβ species. The polyphenol, p-Coumaric acid (pCA), has been known to boost a number of therapeutic benefits. Here, pCA's potential to counteract the negative effects of Aβ42 was investigated. First, pCA was confirmed to reduce Aβ42 fibrillation using an in vitro activity assay. The compound was next examined on Aβ42-exposed PC12 neuronal cells and was found to significantly decrease Aβ42-induced cell mortality. pCA was then examined using an AD Drosophila melanogaster model. Feeding of pCA partially reversed the rough eye phenotype, significantly lengthened AD Drosophila's lifespan, and significantly enhanced the majority of the AD Drosophila's mobility in a sex-dependent manner. The findings of this study suggest that pCA may have therapeutic benefits for AD.
Small molecules as well as peptide-based therapeutic approaches have attracted global interest due to their lower or no toxicity in nature, and their potential in addressing several health complications including immune diseases, cardiovascular diseases, metabolic disorders, osteoporosis and cancer. This study proposed a peptide, GE18 of subtilisin-like peptidase from the virulence factor of aquatic pathogenic fungus Aphanomyces invadans, which elicits anti-cancer and anti-microbial activities. To understand the potential GE18 peptide-induced biological effects, an in silico analysis, in vitro (L6 cells) and in vivo toxicity assays (using zebrafish embryo), in vitro anti-cancer assays and anti-microbial assays were performed. The outcomes of the in silico analyses demonstrated that the GE18 peptide has potent anti-cancer and anti-microbial activities. GE18 is non-toxic to in vitro non-cancerous cells and in vivo zebrafish larvae. However, the peptide showed significant anti-cancer properties against MCF-7 cells with an IC50 value of 35.34 µM, at 24 h. Besides the anti-proliferative effect on cancer cells, the peptide exposure does promote the ROS concentration, mitochondrial membrane potential and the subsequent upregulation of anti-cancer genes. On the other hand, GE18 elicits significant anti-microbial activity against P. aeruginosa, wherein GE18 significantly inhibits bacterial biofilm formation. Since the peptide has positively charged amino acid residues, it targets the cell membrane, as is evident in the FESEM analysis. Based on these outcomes, it is possible that the GE18 peptide is a significant anti-cancer and anti-microbial molecule.
Brain disorders remain the world's leading cause of disability, and account for more hospitalizations and prolonged care than almost all other diseases combined. The majority of drugs, proteins and peptides do not readily permeate into brain due to the presence of the blood-brain barrier (BBB), thus impeding treatment of these conditions.
MD2 pineapple (Ananas comosus) is the second most important tropical crop that preserves crassulacean acid metabolism (CAM), which has high water-use efficiency and is fast becoming the most consumed fresh fruit worldwide. Despite the significance of environmental efficiency and popularity, until very recently, its genome sequence has not been determined and a high-quality annotated proteome has not been available. Here, we have undertaken a pilot proteogenomic study, analyzing the proteome of MD2 pineapple leaves using liquid chromatography-mass spectrometry (LC-MS/MS), which validates 1781 predicted proteins in the annotated F153 (V3) genome. In addition, a further 603 peptide identifications are found that map exclusively to an independent MD2 transcriptome-derived database but are not found in the standard F153 (V3) annotated proteome. Peptide identifications derived from these MD2 transcripts are also cross-referenced to a more recent and complete MD2 genome annotation, resulting in 402 nonoverlapping peptides, which in turn support 30 high-quality gene candidates novel to both pineapple genomes. Many of the validated F153 (V3) genes are also supported by an independent proteomics data set collected for an ornamental pineapple variety. The contigs and peptides have been mapped to the current F153 genome build and are available as bed files to display a custom gene track on the Ensembl Plants region viewer. These analyses add to the knowledge of experimentally validated pineapple genes and demonstrate the utility of transcript-derived proteomics to discover both novel genes and genetic structure in a plant genome, adding value to its annotation.
Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics in order to defeat multidrug-resistant bacteria such as Streptococcus pneumoniae. In this study, thirteen antimicrobial peptides were designed based on two natural peptides indolicidin and ranalexin. Our results revealed that four hybrid peptides RN7-IN10, RN7-IN9, RN7-IN8, and RN7-IN6 possess potent antibacterial activity against 30 pneumococcal clinical isolates (MIC 7.81-15.62µg/ml). These four hybrid peptides also showed broad spectrum antibacterial activity (7.81µg/ml) against S. aureus, methicillin resistant S. aureus (MRSA), and E. coli. Furthermore, the time killing assay results showed that the hybrid peptides were able to eliminate S. pneumoniae within less than one hour which is faster than the standard drugs erythromycin and ceftriaxone. The cytotoxic effects of peptides were tested against human erythrocytes, WRL-68 normal liver cell line, and NL-20 normal lung cell line. The results revealed that none of the thirteen peptides have cytotoxic or hemolytic effects at their MIC values. The in silico molecular docking study was carried out to investigate the binding properties of peptides with three pneumococcal virulent targets by Autodock Vina. RN7IN6 showed a strong affinity to target proteins; autolysin, pneumolysin, and pneumococcal surface protein A (PspA) based on rigid docking studies. Our results suggest that the hybrid peptides could be suitable candidates for antibacterial drug development.
Three new variants of acidic proline-rich proteins (At, Au, Aw) were found in human parotid saliva by isoelectric focusing and basic gel electrophoresis. Electrophoretic comparison of the purified proteins and their tryptic peptides suggested minor charge and size differences from other acidic PRPs. Genetic and biochemical studies indicate that the At and Aw proteins are allelic products of the PRH1 locus. Gene frequencies of the At productive allele (PRH1(6)) in Japanese, Chinese, and Malays were 0.008, 0.012, and 0.004, respectively. The Au protein was also found in Japanese (2 in 746 samples), Chinese (1 in 215 samples), and Malays (1 in 220 samples), however, the Aw protein was found only in one Japanese (n = 746). These three proteins were not found in 106 Indian subjects.
SPRY domain- and SOCS box-containing proteins SPSB1, SPSB2, and SPSB4 interact with inducible nitric oxide synthase (iNOS), causing the iNOS to be polyubiquitinated and targeted for degradation. Inhibition of this interaction increases iNOS levels, and consequently cellular nitric oxide (NO) concentrations, and has been proposed as a potential strategy for killing intracellular pathogens. We previously described two DINNN-containing cyclic peptides (CP1 and CP2) as potent inhibitors of the murine SPSB-iNOS interaction. In this study, we report the crystal structures of human SPSB4 bound to CP1 and CP2 and human SPSB2 bound to CP2. We then used these structures to design a new inhibitor in which an intramolecular hydrogen bond was replaced with a hydrocarbon linkage to form a smaller macrocycle while maintaining the bound geometry of CP2 observed in the crystal structures. This resulting pentapeptide SPSB-iNOS inhibitor (CP3) has a reduced macrocycle ring size, fewer nonbinding residues, and includes additional conformational constraints. CP3 has a greater affinity for SBSB2 ( KD = 7 nM as determined by surface plasmon resonance) and strongly inhibits the SPSB2-iNOS interaction in macrophage cell lysates. We have also determined the crystal structure of CP3 in complex with human SPSB2, which reveals the structural basis for the increased potency of CP3 and validates the original design.
Matched MeSH terms: Peptides, Cyclic/pharmacology; Peptides, Cyclic/chemistry*; Intracellular Signaling Peptides and Proteins/metabolism; Intracellular Signaling Peptides and Proteins/chemistry*
Actinidin was used to pretreat the bovine hide and ultrasonic wave (53 kHz and 500 W) was used for the time durations of 2, 4 and 6 h at 60 °C to extract gelatin samples (UA2, UA4 and UA6, respectively). Control (UAC) gelatin was extracted using ultrasound for 6 h at 60 °C without enzyme pretreatment. There was significant (p < 0.05) increase in gelatin yield as the time duration of ultrasound treatment increased with UA6 giving the highest yield of 19.65%. Gel strength and viscosity of UAC and UA6 extracted gelatin samples were 627.53 and 502.16 g and 16.33 and 15.60 mPa.s, respectively. Longer duration of ultrasound treatment increased amino acids content of the extracted gelatin and UAC exhibited the highest content of amino acids. Progressive degradation of polypeptide chains was observed in the protein pattern of the extracted gelatin as the time duration of ultrasound extraction increased. Fourier transform infrared (FTIR) spectroscopy depicted loss of molecular order and degradation in UA6. Scanning electron microscopy (SEM) revealed protein aggregation and network formation in the gelatin samples with increasing time of ultrasound treatment. The study indicated that ultrasound assisted gelatin extraction using actinidin exhibited high yield with good quality gelatin.
Macrobrachium rosenbergii nodavirus (MrNv) causes white tail disease (WTD) in giant freshwater prawns, which leads to devastating economic losses in the aquaculture industry. Despite extensive research on MrNv, there is still no antiviral agent to treat WTD. Thus, the main aim of this study was to identify potential anti-MrNv molecules. A 12-mer phage-displayed peptide library was biopanned against the MrNv virus-like particle (VLP). After four rounds of biopanning, two dominant phages harbouring the amino acid sequences HTKQIPRHIYSA and VSRHQSWHPHDL were selected. An equilibrium binding assay in solution was performed to determine the relative dissociation constant (KDrel) of the interaction between the MrNv VLP and the selected fusion phages. Phage-HTKQIPRHIYSA has a KDrel value of 92.4±22.8 nM, and phage-VSRHQSWHPHDL has a KDrel value of 12.7±3.8 nM. An in-cell elisa was used to determine the inhibitory effect of the synthetic peptides towards the entry of MrNv VLP into Spodoptera frugiperda (Sf9) cells. Peptides HTKQIPRHIYSA and VSRHQSWHPHDL inhibited the entry of the MrNv VLP into Sf9 cells with IC50 values of 30.4±3.6 and 26.5±8.8 µM, respectively. Combination of both peptides showed a significantly higher inhibitory effect with an IC50 of 4.9±0.4 µM. An MTT assay revealed that the viability of MrNv-infected cells increased to about 97 % in the presence of both peptides. A real-time RT-PCR assay showed that simultaneous application of both peptides significantly reduced the number of MrNv per infected cell, from 97±9 to 11±4. These peptides are lead compounds which can be further developed into potent anti-MrNv agents.