Serine Protease Inhibitory Activity Research Articles

15-lipoxygenase and serine protease inhibitory activities of Heritiera fomes (buch. -ham), a mangrove plant of the Sundarbans

15-Lipoxygenase (15-Lox) oxidizes fatty acid, thereby producing inflammatory mediators which cause diverse inflammatory diseases such as atherosclerosis, asthma, cancer etc. Serine proteases are enzymes that activate tissue factor VII by proteolytic cleavage, eventually activating blood coagulation pathway. Antioxidants play role in 15-Lox and serine protease inhibition to dampen elevation of cytokine levels, thereby function as anti-inflammation and anticoagulation agent. In this study, we examined 15-Lox and serine protease inhibitory activities of the ethanolic bark and leaf crude extract of Heritiera fomes. The crude bark extract (HFB) exhibited 15-Lox and serine protease inhibition with IC50 117.14 and 409.61 μg/ml, respectively. Chromatographically separated active fraction HFBPF1 demonstrated highest 15-Lox and serine protease inhibitory activity with IC50 62.68 and 72.62 μg/ml, respectively. The antioxidant activity and total flavonoid content were substantially increased in the chromatographic fractions compared to the crude extracts. The LC-MS/MS analysis of bark and leaf active fractions revealed the presence of 2,4,6-octatrienal, apigenin 7 (4˝-Z-p-coumerylglucoside), brosimacutin B, gambrin B2, kandelin A1 and tetraneurin A which we report for the first time in H. fomes. Therefore, we conclude the significant augmentation in the 15-Lox and serine protease inhibition activity of the fractions which could be exerted by the enriched flavonoid content.

The Trypsin Inhibitory Activity of Vigna unguiculata ssp. Sesquipedalis (Hawari Mae) Seeds Grown in Sri Lanka was Evaluated

Aims: This study aimed to screen the entire seed sample of Vigna unguiculata ssp sesquipedalis (Hawari mae) for serine protease inhibitory activity. Additionally, the study explored the impact of various factors such as temperature, pH, metal ions, detergent, oxidizing and reducing agents on the inhibitory activity. Methodology: A batch of Hawari Mae seeds was obtained from the Plant Genetic Resources Center in Sri Lanka. A concentration gradient of aqueous seed extracts was tested for Serine Inhibitory Activity (SIA). To carry out the SIA assay, seed extracts were mixed with trypsin in phosphoric acid buffer (pH 7.6) and casein was added as the substrate. The samples were then incubated at 37°C and trichloroacetic acid was used to stop the reaction. The supernatants were checked for absorbance at 280 nm and the percentage of serine inhibitory activity (SIA%) was calculated. All experiments were conducted three times to ensure accuracy. The inhibitory activities were tested under various conditions, including different temperatures, pH levels, metal ions, detergents, and oxidizing and reducing agents. Results: The crude extract containing 10% of the substance showed the highest level of trypsin inhibitory activity at 96.03±0.005%. This particular extract was selected for further analysis. The study revealed that the enzyme inhibition activity was highest at a temperature of 37°C (95.42±0.006%) and a pH of 7.6 (95.71±0.003%). It was observed that all tested metal ions, except Cu2+, significantly reduced (P<0.05) the trypsin inhibitory activity in Hawari mae. The presence of the detergent Triton X-100 did not significantly affect (P>0.05) the trypsin inhibitory activity of Hawari mae. However, the presence of DMSO and dithiothreitol significantly (P<0.05) reduced its activity. Conclusion: Significant trypsin inhibitory activity was observed in the seed extract of Hawari mae. Further studies on the effects of various physio-chemical parameters can aid in the purification and isolation of trypsin inhibitors.

The versatile role of Serpina3c in physiological and pathological processes: a review of recent studies.

Murine Serpina3c belongs to the family of serine protease inhibitors (Serpins), clade "A" and its human homologue is SerpinA3. Serpina3c is involved in some physiological processes, including insulin secretion and adipogenesis. In the pathophysiological process, the deletion of Serpina3c leads to more severe metabolic disorders, such as aggravated non-alcoholic fatty liver disease (NAFLD), insulin resistance and obesity. In addition, Serpina3c can improve atherosclerosis and regulate cardiac remodeling after myocardial infarction. Many of these processes are directly or indirectly mediated by its inhibition of serine protease activity. Although its function has not been fully revealed, recent studies have shown its potential research value. Here, we aimed to summarize recent studies to provide a clearer view of the biological roles and the underlying mechanisms of Serpina3c.

Antioxidant, Antimicrobial and Protease Inhibitory Activity of Potato Peel.

Background: Due to having health hazards of artificial preservatives, natural preservatives having anti-enzymatic, antimicrobial, and antioxidant properties are drawing the attention of food scientists. Objectives: Potato peel can be a cheap and available source of preservatives as it is considered a waste after processing its tuber. Methods: We evaluated the serine protease inhibitory activity, antibacterial activity by Disc diffusion assay, and antioxidant properties by DPPH free radical scavenging assay and Ferric-ion reducing antioxidant power assay (FRAP) of crude methanol and aqueous extract of potato peel. In addition, Total phenol, flavonoid, and tannin content were also quantified in both crude extracts. Results: Crude methanol extract was found more potential to have significant serine protease inhibition activity (IC50 = 534.87 μg/mL), DPPH free radical scavenging activity (IC50 = 183.56 μg/mL), and FRAP (ferric reducing antioxidant power) value of 351.81 µM Fe(II)/100µg of dried extract. Moreover, the total phenol, flavonoid and tannin content of the methanol extract were higher than the aqueous extract. Also, crude methanol extract showed maximum zone of inhibition (ZOI) against Vibrio cholera and Salmonella typhi (13.63 ± 0.53 and 13.25 ± 0.35 mm respectively). Later, column chromatography for the enrichment of total flavonoid content of methanol fractions exhibited elevated flavonoid content and serine protease inhibitory activity than crude methanol extract. Conclusion: This study showed, the methanol extract of potato peel is more potential than water extract.

Evaluation of Antioxidant and Anticoagulation Activity of Piper chaba Hunter Stem

Background: Piper chaba Hunter, a flowering vine of the Piperaceae family, has long been used in South Asian countries for culinary purposes and traditionally in fat-rich meat preparation. The curative potential of this herb is of great interest to be studied.
 Objectives: The antioxidant and anticoagulation potential, as well as total phenolic and flavonoid content, were evaluated using cold and boiled water extract separately from the dried and ground stem.
 Methods: Antioxidant potential was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. The anticoagulation activity was evaluated by serine protease inhibition assay and prothrombin time (PT) assay. Folin–Ciocalteu (FC) reagent and aluminum complex (AlCl3 ) were used to assess total phenolic content and total flavonoid content, respectively.
 Results: DPPH scavenging assay revealed the IC50 value of 125.52 µg.mL-1 and 157.94 µg.mL-1 for boiled and cold water extract, respectively. Potent ferric reducing potential (FRAP) was observed as 142.87 µM and 135.37 µM of ferrous equivalent per 100 µg for boiled and cold water extract, respectively. The IC50 value of serine protease inhibitory activity was found as 182 µg.mL-1 and 161.12 µg.mL-1 for cold and boiled water extract, respectively. The PT time was 27.00 min for boiled water extract and 24.68 min for cold water extract. Significant phenolic and flavonoid content was also found in the test sample.
 Conclusion: P. chaba stem extract possesses potent antioxidant and anticoagulation activity, which can neutralize oxidative free radicals and have a vasodilation effect in oxidative and inflammatory diseases.

In-vitro anti-inflammatory activity of serine protease inhibitor from Cassia siamea and Dolichos biflorus: A comparative study.

Cassia siamea is a nonedible legume belonging to Fabaceae. The seed of C. siamea contains ~16% of protein. The study reports the biochemical characterization of purified novel serine protease inhibitor from seeds of C. siamea, aimed with assessing the anti-inflammatory activity. The seed extract was subjected to ammonium sulfate precipitation followed by fast protein liquid chromatography (FPLC)-anion exchange chromatography and affinity-chromatography to obtain a relative pure protease inhibitor. Thirty-fivefold purification with the specific activity of 250 U/mg of trypsin inhibitory unitwas obtained. The characterization of protease inhibitor for optimum temperature, pH, and metal ions were measured using N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA) assay and casein zymogram. The C. siamea trypsin inhibitor (CsTI) has a relative molecular mass of 25.540 kDa. Purified CsTI and Dolichos biflorus were tested for anti-inflammatory efficacy against A549 and RAW264.7 cell lines. The inhibitory activity of both purified inhibitors are comparable and are potent toward anti-inflammatory activity. The purified inhibitor shows to be a promising candidate as anti-inflammatory agent by targeting the serine proteases.

Conjugation of a Cationic Cell-Penetrating Peptide with a Novel Kunitzin-like Trypsin Inhibitor: New Insights for Enhancement of Peptide Bioactivities.

Cationic cell-penetrating peptides (CPPs), such as transactivator of transcription (TAT) peptide, have been proposed as effective drug carriers to improve intracellular delivery of biological macromolecules. Amphibian skin-derived Kunitz-type trypsin inhibitors (KTIs), short counterparts of KTIs from plant sources, were found to possess potent serine protease inhibitory activity. However, poor transmembrane permeability of these molecules has largely hindered the study of the full spectrum of their biological actions. As a result, this study aimed to extend the biological activities of amphibian KTIs by their conjugation to cationic CPPs. Herein, a novel peptide (kunitzin-OV2) and its phenylalanine-substituted analogue F9-kunitzin-OV2 (F9-KOV2) were evaluated for inhibition of trypsin/chymotrypsin and showed weak antibacterial activity against Escherichia coli (E. coli). As expected, the conjugation to TAT peptide did not increase membrane lysis compared with the original kunitzin-OV2, but effectively assisted this complex to enter cells. TAT-kunitzin-OV2 (TAT-KOV2) exhibited a 32-fold increase in antibacterial activity and an enhanced bactericidal rate against E. coli. In addition, the conjugation enabled the parent peptides to exhibit antiproliferative activity against cancer cells. Interestingly, TAT-F9-kunitzin-OV2 (TAT-F9-KOV2) showed stronger antiproliferative activity against human breast cancer (MCF-7) and human glioblastoma (U251MG) cell lines, which TAT-KOV2 did not possess. Moreover, TAT-F9-KOV2 showed a 20–25-fold increase in antiproliferative capacity against human lung cancer (H157, H460) cell lines compared with TAT-KOV2. Therefore, the conjugation of CPPs effectively solves the problem of cell penetration that short KTIs lack and provides evidence for new potential applications for their subsequent development as new antibacterial and anticancer agents.

Serine Proteases and Their Inhibitors Affect the Rate of GnRH Neuronal Migration in the Embryonic Chick Model: A Thesis Proposal

Development in an organism is a highly complex task that requires a specific sequence for proper function. One of these tasks is neuronal migration and the extracellular cues that help to guide neurons to their appropriate locations. If neurons do not migrate to their appropriate locations, then there are abnormal neural connections, which can result in neuronal migration disorders (NMD). It has been shown that the inhibition and stimulation of migration may be balanced due to effects of serine protease inhibitors and serine proteases. Serine proteases and their inhibitors can alter the various chemoattraction-signaling cues and thereby modulate neuronal migratory processes. Furthermore, there exists a delicate balance between serine proteases and their inhibitors to modulate migration of neurons within development. Thus, by understanding how the balance of serine protease and serine protease inhibitor activity works, one can further understand how these changes affect neuronal migration in development. Experiments to test in vivo neuronal migration of chick GnRH neurons during embryogenesis were investigated to elucidate the role these proteins play in migration. Protein coated beads were inserted and GnRH levels measured to control. Such experimentation is crucial, as these studies are the first to explore the role of proteases in neural migration in an in vivo model. These findings indicate that the ability to initiate migration lies inherently within the neuron itself such that changes of the extracellular matrix composition are irrelevant in the initial timing. Neurons entering the CNS earlier in trypsin-treated embryos indicates continuous movement may be a cell autonomous event with trypsin-induced proteolysis. In other words, the ability of GnRH neurons to migrate across glial boundaries and through the brain to its target site is independent of further maturation of the neuron or the brain. Taken together, this study can provide knowledge regarding these proteins and their relation to development. This knowledge can potentially lead to therapies that can provide ameliorative care for patients suffering with NMD.

Pan-cancer analysis of osteogenesis imperfecta causing gene SERPINF1.

Osteogenesis imperfecta (OI) type VI causative gene SERPINF1, encodes a member of the serpin family that does not display the serine protease inhibitory activity shown by many of the other serpin proteins. The encoded protein (pigment epithelium-derived factor, PEDF) has anti-tumor, anti-angiogenesis, anti-inflammation, nutrition and nerve protection functions, and participates in fat metabolism. In this paper, a series of bioinformatics analyses were conducted based on the regulation of SERPINF1 in the human. Pan-cancer analysis of SERPINF1 revealed it to play a role in the prognosis of tumors, especially in KIRC, and that high expression of SERPINF1 leads to a poor prognosis of the disease, the occurrence of which is largely related to the high expression of SERPINF1 leading to immune infiltration of cancer associated fibroblasts. Mutation analysis found that SERPINF1 had eight identical amino acids alterations sites with different in both cancer and OI patients. which hints the possible relationship between genotype and phenotype.

Short-term warming inhibits polyphenol oxidase activity and influences free amino acid accumulation and de novo synthesis of tyrosine in fresh-cut potato

Potatoes cut immediately after being taken out from cold storage easily undergo browning. Researchers have reported that long-term warming alleviates the browning of fresh-cut potatoes. However, long-term warming is not commercially applicable. The present study investigated the effect of short-term warming (SW) at 25 °C for 12 h on the browning of fresh-cut potatoes. The browning index of potatoes stored at 4 °C for 8 months was tested. The analysis revealed that SW efficiently blocked enzymatic browning by inhibiting polyphenol oxidase (PPO) activity, decreasing total phenolic content and malondialdehyde (MDA) content, and increasing peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activity, and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,20-azino-bis (3-ethylben zothiazoline) 6-sulphonic acid (ABTS) inhibition rates. Moreover, SW treatment induced the expression of the serine protease inhibitor (SPI) gene and enhanced SPI activity, increased the soluble protein content and decreased free tyrosine, and lysine content in fresh-cut potatoes during the 5 d storage at 2∼4 °C. The contents of glutamic acid, aspartic acid, and proline in the fresh-cut potatoes increased after SW treatment. Furthermore, the amino acid complementation experiments showed that tyrosine and lysine aggravated browning while glutamic acid and aspartic acid reduced browning. The SW treatment reduced the activity of chorismate mutase (CM), repressed the transcript levels of CM synthesis-related genes (CM1 and CM2), and inhibited free tyrosine synthesis. These results indicate that SW treatment alleviates the browning of potato tubers after cold storage probably due to its influence on PPO, metabolism of tyrosine, other FAAs and phenolics, and antioxidants.

Nuclear polyhedrosis virus‐induced proteomic changes in Antheraea mylitta

AbstractInnate immunity, the evolutionarily conserved defence system, has been extensively explored in insect models like Drosophila and mosquito species for their immune responses towards diverse pathogens. Viruses being obligate parasites take over cellular macromolecular machinery and routinely control intracellular signalling pathways through the direct or indirect control of kinases and phosphatases. Domestic silkworm, Bombyx mori is an economically important insect. Wild silkworm Antheraea mylitta produces a unique variety of silk in terms of its colour, lustre and strength called as Tasar silk. Both the silkworms vary in their immune response to nuclear polyhedrosis virus (NPV). NPV causes 80% of crop losses in B. mori, interestingly there are no documented reports of NPV infection in A. mylitta. To investigate the mechanism of A. mylitta's immune response to NPV infection, we analysed viral induced proteins through proteomic approach (SDS‐PAGE and LC–MS/MS). We report the expression of a myotubularin‐related protein (MTMR6) of 23 kDa at 72 h post infection (hpi) indicating its role in host immunity as a phosphatase enzyme. And also, a differentially expressed serpin‐like protein of 67 kDa was upregulated in a significant way from 72 hpi further strengthening the immune response by suppressing the viral replication through serine protease inhibitory activity. This observation was further confirmed through qPCR studies on virus proliferation using lef‐1 gene which clearly indicated a reduction in viral load from 72 hpi onwards in A. mylitta silkworms.

Assessment of Serine Protease Inhibitory Activities of Phytoconstituents of Four Medicinal Plants Traditionally Used in Viral Diseases Management

Aqueous extract of leaves of Momordica charantia, Hymenocardia acida, Lawsonia inermis and fruit of Xylopia aethiopica have traditionally been used in the management of several viral diseases such as measles, HIV/AIDS, leprosy, meningitis and yellow fever. The mechanism of their action had been reported to be due to their high antioxidant activities which mop up reactive oxygen/nitrogen radicals. We provide preliminary report that the mechanism may also be due to inhibition of some key proteases important in the pathology of the viral infections.Literature search and laboratory analysis confirm the presence of naringenin, apigenin, epicatechin, biochanin A, luteolin, etc. in M. charantia ; diaphneside, rutin, lawsone, daphnorin, caffeoyl alcohol, etc. in L. inermis ; kauran-16-alpha-ol, xylopic acid, lanuginosine, crebanine, piperine, etc in X. aethiopica and kaempferol 3-O-glycoside, homoorientin, hymenocardine, orientin as present in H. acida . The compounds were docked against furin and TMPRSS2 to estimate their respective binding energies. Their peptides were also extracted and their trypsin inhibition determined.The results obtained showed that many of the molecules have low binding energies without violating Lipinski’s rule of 5. M. charantia, H. acida, L. inermis and X. aethiopica contain 5.7±0.5 mg/ml, 1.0±0.2 mg/ml, 1.8±0.1 mg/ml and 28.3±4.1 mg/ml concentration of peptides, respectively, all of which are potent inhibitors of trypsin with peptides from M. charantia seeds having the lowest inhibition constant (Ki) of 13 μg/ml.It is concluded that the antiviral activities of the plant extracts could also be due to inhibition of some proteases involved in the pathology of the infection.

Gene therapy for alpha 1-antitrypsin deficiency with an oxidant-resistant human alpha 1-antitrypsin.

Alpha 1-antitrypsin (AAT) deficiency, a hereditary disorder characterized by low serum levels of functional AAT, is associated with early development of panacinar emphysema. AAT inhibits serine proteases, including neutrophil elastase, protecting the lung from proteolytic destruction. Cigarette smoke, pollution, and inflammatory cell–mediated oxidation of methionine (M) 351 and 358 inactivates AAT, limiting lung protection. In vitro studies using amino acid substitutions demonstrated that replacing M351 with valine (V) and M358 with leucine (L) on a normal M1 alanine (A) 213 background provided maximum antiprotease protection despite oxidant stress. We hypothesized that a onetime administration of a serotype 8 adeno-associated virus (AAV8) gene transfer vector coding for the oxidation-resistant variant AAT (A213/V351/L358; 8/AVL) would maintain antiprotease activity under oxidant stress compared with normal AAT (A213/M351/M358; 8/AMM). 8/AVL was administered via intravenous (IV) and intrapleural (IPL) routes to C57BL/6 mice. High, dose-dependent AAT levels were found in the serum and lung epithelial lining fluid (ELF) of mice administered 8/AVL or 8/AMM by IV or IPL. 8/AVL serum and ELF retained serine protease–inhibitory activity despite oxidant stress while 8/AMM function was abolished. 8/AVL represents a second-generation gene therapy for AAT deficiency providing effective antiprotease protection even with oxidant stress.

Truncated reactive center loop decrease the inhibitory activity of Antheraea pernyi serine protease inhibitor 6.

Here, we assessed the effect of a systematic change in reactive center loop (RCL) length, N-terminal to the reactive center, on the inhibitory activity of the recombinant Apserpin-6. The domain prediction results indicated that the RCL is located between the amino acid numbered 359-379 at the C-terminal of Apserpin-6. The N-terminal variable region for amino acid positions P7-P1 of the RCL of Apserpin-6 was truncated or extended by residue deletion or insertion using site-directed mutagenesis. The recombinant Apserpin-6 with one or two residues insertion in RCL had no effect on prophenoloxidase (proPO) activity, whereas deletion of one or two residues in RCL lowered the efficiency of inhibition of Apserpin-6. The results of this study will facilitate the understanding of inhibition mechanism of RCL on proPO activity.

Inhibition of Serine Protease Activity Protects Against High Fat Diet-Induced Inflammation and Insulin Resistance

Recent evidence suggests that enhanced protease-mediated inflammation may promote insulin resistance and result in diabetes. This study tested the hypothesis that serine protease plays a pivotal role in type 2 diabetes, and inhibition of serine protease activity prevents hyperglycemia in diabetic animals by modulating insulin signaling pathway. We conducted a single-center, cross-sectional study with 30 healthy controls and 57 patients with type 2 diabetes to compare plasma protease activities and inflammation marker between groups. Correlations of plasma total and serine protease activities with variables were calculated. In an in-vivo study, LDLR−/− mice were divided into normal chow diet, high-fat diet (HFD), and HFD with selective serine protease inhibition groups to examine the differences of obesity, blood glucose level, insulin resistance and serine protease activity among groups. Compared with controls, diabetic patients had significantly increased plasma total protease, serine protease activities, and also elevated inflammatory cytokines. Plasma serine protease activity was positively correlated with body mass index, hemoglobin A1c, homeostasis model assessment-insulin resistance index (HOMA-IR), tumor necrosis factor-α, and negatively with adiponectin concentration. In the animal study, administration of HFD progressively increased body weight, fasting glucose level, HOMA-IR, and upregulated serine protease activity. Furthermore, in-vivo serine protease inhibition significantly suppressed systemic inflammation, reduced fasting glucose level, and improved insulin resistance, and these effects probably mediated by modulating insulin receptor and cytokine expression in visceral adipose tissue. Our findings support the serine protease may play an important role in type 2 diabetes and suggest a rationale for a therapeutic strategy targeting serine protease for clinical prevention of type 2 diabetes.

Preliminary investigations on the serine and aspartic protease inhibitors from <i>Nothopegia</i> <i>beddomei</i>

Aqueous stem bark extract of Nothopegia beddomei was assayed for serine and aspartic protease inhibitors by using trypsin and pepsin as the target enzymes, respectively. Crude bark extract was dialyzed and subjected to inhibition assays. The thermal stabilities of serine and aspartic protease inhibitors were studied by incubating the extract at 4 oC, room temperature and 37 oC for a period of one month and subjecting to higher temperatures (55 oC, 75 oC and 95 oC) for 15 minutes. The crude bark extract of N. beddomei exhibited serine and aspartic protease inhibitory activities. However, the serine protease inhibitory activity was significantly higher. The approximate molecular mass of both serine and aspartic protease inhibitors were more than 8 kDa. Both types of inhibitors were identified as mixtures of thermally stable and labile compounds due to their variations in inhibitory activities with time at different temperatures. Attempts made to purify the protease inhibitors using ion exchange chromatography and ammonium sulphate precipitation were unsuccessful. In conclusion, the results indicate both serine and aspartic protease inhibition activities in N. beddomei bark extract are governed by mixtures of protenaceous and non-protenaceous molecules.

Bldesin, the first functionally characterized pathogenic fungus defensin with Kv1.3 channel and chymotrypsin inhibitory activities

Fungus defensin is a kind of important natural peptide resource, such as plectasin from the soil fungus Pseudoplectania nigrella with potential application in the antimicrobial peptide lead drug discovery. Here, a fungus defensin named Bldesin with Kv1.3 channel and serine protease inhibitory activities was first explored. By GST-Bldesin fusion expression and enterokinase cleaving strategy, recombinant Bldesin was obtained successfully. Antimicrobial assays showed that Bldesin had potent activity against Gram-positive Staphylococcus aureus, but had no effect on Gram-negative Escherichia coli. Electrophysiological experiments showed that Bldesin had Kv1.3 channel inhibitory activity. Serine protease inhibitory associated experiments showed that Bldesin had unique chymotrypsin protease inhibitory, elastase protease inhibitory, and serine protease-associated coagulation inhibitory activities. To the best of our knowledge, Bldesin is the first functionally characterized pathogenic fungus defensin with Kv1.3 channel and chymotrypsin inhibitory activities and highlighted novel pharmacological effects of fungus-derived defensin peptides.

Therapeutic potential of alpha-1 antitrypsin in human disease.

Alpha-1 antitrypsin (AAT), an alpha globulin glycoprotein, is a member of the serine protease inhibitor (serpin) superfamily. The clinical significance of AAT is highlighted by AAT deficiency. Genetic deficiency of AAT can present as several neutrophilic diseases associated with emphysema, liver cirrhosis, panniculitis, and systemic vasculitis. Recently, animal and human studies have shown that AAT can control inflammatory, immunological, and tissue-protective responses. In addition, AAT treatment can prevent overt hyperglycemia, increase insulin secretion, and reduce cytokine-mediated apoptosis of pancreatic β-cells in diabetes. These multifunctional roles of AAT draw attention to the glycoprotein’s therapeutic potential for many inflammatory and autoimmune diseases beyond AAT deficiency. As underlying mechanisms, recent studies have suggested the importance of serine protease inhibitory activity of AAT in obesity-associated insulin resistance, chronic obstructive pulmonary disease, and cystic fibrosis. In this review, we explore the multiple functions of AAT, in particular, the anti-inflammatory and serine protease inhibitory functions, and AAT’s therapeutic potential in a variety of human diseases through published literature.

Biological Activity of Serine Protease Inhibitor Isolated from the Seeds of Phaseolus vulgaris

Seed flour extract of local common bean cultivar Baspa inhibited gut proteases of Spodoptera litura Fab. The inhibitor protein was purified by ammonium sulphate precipitation and gel filtration chromatography. Freshly laid eggs of Pieris brassicae L. treated with 220-µg inhibitor protein showed 89.60% reduction and delay in hatching by 2 days as compared to control. Feeding neonate larvae of P. brassicae on cabbage leaf discs coated with inhibitor protein (79.25 and 118.88 µg) for 6 days resulted in 50 and 89% larval mortality and reduction in larval growth by 20.77 and 48.47% as compared to untreated control. The treated larvae (118.88 µg) shifted on untreated leaf discs showed mortality after 3 days. However, the growth of treated larvae (79.25 µg) fed on untreated leaf discs further decreased to 45.17% showed delayed pupation, deformed pupa formation and no adult emergence in contrast to control larvae.

Anti-inflammatory activity of a thermophilic serine protease inhibitor from extremophile Pyrobaculum neutrophilum

Serine protease inhibitors (serpins) are a superfamily of proteins involved in many important biological processes, including inflammation. Serpins dysfunction-related diseases are mainly treated by augmentation therapy using serpins purified from human plasma. Pnserpin from hyperthermophilic archaeon Pyrobaculum neutrophilum showed protease inhibition activity and high stability. In this study, we examined the anti-inflammatory activity of Pnserpin using xylene-induced acute inflammatory model of mouse ear swelling and lipopolysaccharide (LPS)-induced murine RAW 264.7 macrophages cellular model. The inhibition of mouse ear swelling and the production of pro-inflammatory cytokines in mouse serum or in macrophages cell were used to evaluate the anti-inflammatory effect of Pnserpin. Our results showed that Pnserpin could inhibit the xylene-induced mouse ear swelling and suppress the production of pro-inflammatory cytokines in mouse serum and in LPS-induced RAW264.7 cells. This study indicated that Pnserpin might have anti-inflammatory effect in vivo and in vitro.