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Fulltext Novel angiotensin I-converting enzyme inhibitory peptides derived from an edible mushroom, Pleurotus cystidiosus O.K. Miller identified by LC-MS/MS

Lau CC, Abdullah N, Shuib AS

BMC Complement Altern Med, 2013 Nov 11;13:313.
PMID: 24215325 DOI: 10.1186/1472-6882-13-313

BACKGROUND: Angiotensin I-converting enzyme (ACE) inhibitors have been reported to reduce mortality in patients with hypertension. Compared to chemosynthetic drugs, ACE inhibitors derived from natural sources such as food proteins are believed to be safer for consumption and to have fewer adverse effects. Some edible mushrooms have been reported to significantly reduce blood pressure after oral administration. In addition, mushrooms are known to be rich in protein content. This makes them a potential source of ACE inhibitory peptides. Hence, the objective of the current study was to isolate and characterise ACE inhibitory peptides from an edible mushroom, Pleurotus cystidiosus.
METHODS: ACE inhibitory proteins were isolated from P. cystidiosus based on the bioassay guided purification steps, i.e. ammonium sulphate precipitation, reverse phase high performance liquid chromatography and size exclusion chromatography. Active fraction was then analysed by LC-MS/MS and potential ACE inhibitory peptides identified were chemically synthesized. Effect of in vitro gastrointestinal digestions on the ACE inhibitory activity of the peptides and their inhibition patterns were evaluated.
RESULTS: Two potential ACE inhibitory peptides, AHEPVK and GPSMR were identified from P. cystidiosus with molecular masses of 679.53 and 546.36 Da, respectively. Both peptides exhibited potentially high ACE inhibitory activity with IC50 values of 62.8 and 277.5 μM, respectively. SEC chromatograms and BIOPEP analysis of these peptides revealed that the peptide sequence of the hexapeptide, AHEPVK, was stable throughout gastrointestinal digestion. The pentapeptide, GPSMR, was hydrolysed after digestion and it was predicted to release a dipeptide ACE inhibitor, GP, from its precursor. The Lineweaver-Burk plot of AHEPVK showed that this potent and stable ACE inhibitor has a competitive inhibitory effect against ACE.
CONCLUSION: The present study indicated that the peptides from P. cystidiosus could be potential ACE inhibitors. Although these peptides had lower ACE inhibitory activity compared to commercial antihypertensive drugs, they are derived from mushroom which could be easily obtained and should have no side effects. Further in vivo studies can be carried out to reveal the clear mechanism of ACE inhibition by these peptides.
Potential use of Lentinus squarrosulus mushroom as fermenting agent and source of natural antioxidant additive in livestock feed

Abdullah N, Lau CC, Ismail SM

J Sci Food Agric, 2016 Mar;96(5):1459-66.
PMID: 25926021 DOI: 10.1002/jsfa.7242

Fermenting feed has gained a lot of popularity in recent years owing to its renowned benefits to the livestock and feed quality. In the current study, Lentinus squarrosulus mushroom mycelium was tested for its potential as a fermenting agent and source of natural antioxidant in the feed.
Novel angiotensin I-converting enzyme inhibitory peptides derived from edible mushroom Agaricus bisporus (J.E. Lange) Imbach identified by LC-MS/MS

Lau CC, Abdullah N, Shuib AS, Aminudin N

Food Chem, 2014 Apr 1;148:396-401.
PMID: 24262574 DOI: 10.1016/j.foodchem.2013.10.053

Angiotensin I-converting enzyme (ACE) inhibitors derived from foods are valuable auxiliaries to agents such as captopril. Eight highly functional ACE inhibitory peptides from the mushroom, Agaricus bisporus, were identified by LC-MS/MS. Among these peptides, the most potent ACE inhibitory activity was exhibited by AHEPVK, RIGLF and PSSNK with IC₅₀ values of 63, 116 and 129 μM, respectively. These peptides exhibited high ACE inhibitory activity after gastrointestinal digestion. Lineweaver-Burk plots suggested that AHEPVK and RIGLF act as competitive inhibitors against ACE, whereas PSSNK acts as a non-competitive inhibitor. Mushrooms can be a good component of dietary supplement due to their readily available source and, in addition, they rarely cause food allergy. Compared to ACE inhibitory peptides isolated from other edible mushrooms, AHEPVK, RIGLF and PSSNK have lower IC₅₀ values. Therefore, these peptides may serve as an ideal ingredient in the production of antihypertensive supplements.
Proteomic analysis of antihypertensive proteins in edible mushrooms

Lau CC, Abdullah N, Shuib AS, Aminudin N

J Agric Food Chem, 2012 Dec 19;60(50):12341-8.
PMID: 23190208 DOI: 10.1021/jf3042159

Mushrooms are high in protein content, which makes them potentially a good source of antihypertensive peptides. Among the mushrooms tested, protein extracts from Pleurotus cystidiosus (E1Pc and E5Pc) and Agaricus bisporus (E1Ab and E3Ab) had high levels of antihypertensive activity. The protein extracts were fractionated by reverse-phase high-performance liquid chromatography (RPHPLC) into six fractions. Fraction 3 from E5Pc (E5PcF3) and fraction 6 from E3Ab (E3AbF6) had the highest antihypertensive activities. SDS-PAGE analysis showed E5PcF3 consisted mainly of low molecular weight proteins, whereas E3AbF6 contained a variety of high to low molecular weight proteins. There were 22 protein clusters detected by SELDI-TOF-MS analysis with five common peaks found in E5PcF3 and E3AbF6, which had m/z values in the range of 3940-11413. This study suggests that the antihypertensive activity in the two mushroom species could be due to proteins with molecular masses ranging from 3 to 10 kDa.
Fulltext Extracellular ATP Induced S-Phase Cell Cycle Arrest via P2Y Receptor-Activated ERK Signaling in Poorly Differentiated Oral Squamous Cell Carcinoma SAS Cells

Lau CC, Aminuddin A, Chan KM, Paterson IC, Law LM, Ng PY

Life (Basel), 2021 Nov 02;11(11).
PMID: 34833046 DOI: 10.3390/life11111170

Extracellular ATP in the tumor microenvironment exhibits either pro- or antitumor effect via interaction with P2Y receptors, but the intracellular signaling and functional roles of P2Y receptors in oral squamous cell carcinoma (OSCC) are unclear. We aimed to study the effect of ATP on OSCC cell lines and the potential mechanisms involved. Through GEPIA dataset analysis, high expression levels of mRNA encoding P2Y receptors, the ATP-induced G protein-coupled receptors, were associated with better overall patient survival in head and neck squamous cell carcinoma. qPCR analysis showed that the poorly differentiated OSCC SAS cell line, had higher P2RY1 expression level compared to the well-differentiated H103 and H376 cell lines. Western blotting and flow cytometry analyses revealed that ATP phosphorylated ERK and elevated intracellular calcium signaling in all tested cell lines. A significant S-phase cell cycle arrest was observed in SAS, and preincubation with the MEK inhibitor PD0325901 reversed the ATP-induced S-phase arrest. We further demonstrated that ATP induced a slight reduction in cell count and colony formation yet significant apoptosis in SAS. Overall, we postulate that the ATP-induced S-phase arrest effect in SAS cells may be regulated through P2Y receptor-mediated ERK signaling, thus suggesting a potential antitumor effect of ATP via interaction with its distinct profile of P2Y receptors.
Calcium and vitamin D fortified milk reduces bone turnover and improves bone density in postmenopausal women over 1 year

Kruger MC, Chan YM, Lau LT, Lau CC, Chin YS, Kuhn-Sherlock B, et al.

Eur J Nutr, 2018 Dec;57(8):2785-2794.
PMID: 28975432 DOI: 10.1007/s00394-017-1544-6

PURPOSE: In Malaysia, hip fracture incidence is higher in Chinese women than other ethnic groups. This study compared the effects of a high-calcium vitamin D fortified milk with added FOS-inulin versus regular milk over 1 year on aspects of bone health in Chinese postmenopausal women in Malaysia.
METHODS: One-hundred and twenty-one women (mean age 59 (± 4) years) were randomized into two groups: control (n = 60; regular milk, 428 mg calcium per day) or intervention (n = 61; fortified milk at 1200 mg calcium, 96 mg magnesium, 2.4 mg zinc, 15 μg vitamin D and 4 g FOS-inulin per day). At baseline, weeks 12, 24, 36 and 52, parathyroid hormone (PTH), C-Telopeptide of Type I Collagen (CTx-1), Procollagen I Intact N-Terminal propeptide (PINP) and vitamin D levels were assessed. Bone density (BMD) was measured at baseline and week 52 using a GE Lunar iDXA.
RESULTS: Body mass index, lumbar spine and femoral neck BMD did not differ between groups at baseline. Over 52 weeks, mean plasma 25 (OH) D3 levels increased to 74.8 nmol/L (intervention group) or remained at 63.1 nmol/L (control group) (p
Fulltext The effects of Pandanus tectorius leaf extract on the resistance of White-leg shrimp Penaeus vannamei towards pathogenic Vibrio parahaemolyticus

Anirudhan A, Iryani MTM, Andriani Y, Sorgeloos P, Tan MP, Wong LL, et al.

Fish Shellfish Immunol Rep, 2023 Dec;4:100101.
PMID: 37397801 DOI: 10.1016/j.fsirep.2023.100101

Pandanus tectorius leaf extract effect on the White-leg shrimp Penaeus vannamei tolerance against Vibrio parahaemolyticus were investigated in this study. Thirty shrimp post-larvae measured at approximately 1 cm were exposed for 24 h to 0.5, 1, 2, 3, 4, 5 and 6 g/L leaf extract and subsequently observed for survival and immune-related genes expression (Hsp70, ProPO, peroxinectin, penaeidin, crustin and transglutaminase), followed by determination of their tolerance and histological tissue profiles upon Vibrio challenge. Survival of shrimps treated with 6 g/L of leaf extract improved by up to 95% to controls. Hsp70, crustin, and prophenoloxidase mRNA levels were observed to be 8.5, 10.4, and 1.5-fold higher, respectively. Histopathological analysis of the hepatopancreas and the muscle tissues revealed major tissue degeneration in Vibrio-challenged shrimps but not in shrimps primed with P. tectorius leaf extract. Of all the dose examined, the best pathogen resistance results were obtained with a 24 h incubation of shrimp in 6 g/L P. tectorius methanolic leaf extract. The tolerance towards V. parahaemolyticus might be associated with the increased regulation of Hsp70, prophenoloxidase and crustin upon exposure to the extract, all immune-related proteins essential for pathogen elimination in Penaeid shrimp. The present study primarily demonstrated that P. tectorius leaf extract is a viable alternative for enhancing P. vannamei post-larvae resistance against V. parahaemolyticus, a major bacterial pathogen in aquaculture.
Hsp70 Knockdown in the Brine Shrimp Artemia franciscana: Implication on Reproduction, Immune Response and Embryonic Cuticular Structure

Tiong IKR, Lau CC, Sorgeloos P, Mat Taib MI, Muhammad TST, Danish-Daniel M, et al.

Mar Biotechnol (NY), 2024 Apr 29.
PMID: 38683457 DOI: 10.1007/s10126-024-10318-8

The potential functional role(s) of heat shock protein 70 (Hsp70) in the brine shrimp, Artemia franciscana, a crucial crustacean species for aquaculture and stress response studies, was investigated in this study. Though we have previously reported that Hsp70 knockdown may have little or no impact on Artemia development, the gestational survival and number of offspring released by adult females were impaired by obscuring Hsp70 synthesis. Transcriptomic analysis revealed that several cuticle and chitin synthetic genes were downregulated, and carbohydrate metabolic genes were differentially expressed in Hsp70-knockdown individuals. A more comprehensive microscopic examination performed in this study revealed exoskeleton structural destruction and abnormal eye lenses featured in Hsp70-deficient adult females 48 h after Hsp70 dsRNA injection. Cysts produced by these Hsp70-deficient broods, instead, had a defective shell and were smaller in size, whereas nauplii had shorter first antennae and a rougher body epicuticle surface. Changes in carbohydrate metabolism caused by Hsp70 knockdown affected glycogen levels in adult Artemia females, as well as trehalose in cysts released from these broods, indicating that Hsp70 may play a role in energy storage preservation. Outcomes from this work provided novel insights into the roles of Hsp70 in Artemia reproduction performance, cyst formation, and exoskeleton structure preservation. The findings also support our previous observation that Hsp70 knockdown reduced Artemia nauplius tolerance to bacterial pathogens, which could be explained by the fact that loss of Hsp70 downregulated several Toll receptor genes (NT1 and Spaetzle) and reduced the integrity of the exoskeleton, allowing pathogens to enter and cause infection, ultimately resulting in mortality.