Expand and Shrink: Federated Learning with Unlabeled Data Using Clustering.

The amalgamation of the Internet of Things (IoT) and federated learning (FL) is leading the next generation of data usage due to the possibility of deep learning with data privacy preservation. The FL architecture currently assumes labeled data samples from a client for supervised classification, which is unrealistic. Most research works in the literature focus on local training, update receiving, and global model updates. However, by principle, the labeling must be performed on the client side because the data samples cannot leave the source under the FL principle. In the literature, a few works have proposed methods for unlabeled data for FL using "class-prior probabilities" or "pseudo-labeling". However, these methods make either unrealistic or uncommon assumptions, such as knowing class-prior probabilities are impractical or unavailable for each classification task and even more challenging in the IoT ecosystem. Considering these limitations, we explored the possibility of performing federated learning with unlabeled data by providing a clustering-based method of labeling the sample before training or federation. The proposed work will be suitable for every type of classification task. We performed different experiments on the client by varying the labeled data ratio, the number of clusters, and the client participation ratio. We achieved accuracy rates of 87% and 90% by using 0.01 and 0.03 of the truth labels, respectively.

Solute Carrier Nucleoside Transporters in Hematopoiesis and Hematological Drug Toxicities: A Perspective.

Anticancer nucleoside analogs produce adverse, and at times, dose-limiting hematological toxicities that can compromise treatment efficacy, yet the mechanisms of such toxicities are poorly understood. Recently, cellular nucleoside transport has been implicated in normal blood cell formation with studies from nucleoside transporter-deficient mice providing additional insights into the regulation of mammalian hematopoiesis. Furthermore, several idiopathic human genetic disorders have revealed nucleoside transport as an important component of mammalian hematopoiesis because mutations in individual nucleoside transporter genes are linked to various hematological abnormalities, including anemia. Here, we review recent developments in nucleoside transporters, including their transport characteristics, their role in the regulation of hematopoiesis, and their potential involvement in the occurrence of adverse hematological side effects due to nucleoside drug treatment. Furthermore, we discuss the putative mechanisms by which aberrant nucleoside transport may contribute to hematological abnormalities and identify the knowledge gaps where future research may positively impact treatment outcomes for patients undergoing various nucleoside analog therapies.

Phytochemicals from Carissa carandas with potent cytotoxic and anti-inflammatory activities.

Six natural products (1-6) were isolated from the fresh leaves of Carissa carandas including ursolic acid (1), ursolic acid-γ-lactone (2), 27-O-Z-p-coumaroyl ursolic acid (3), 23-hydroxy ursolic acid (4), uvaol (5) and ursolic aldehyde (6). Their structure elucidation was done by modern spectroscopic techniques including 1H-NMR, 13C-NMR and comparison with reported data. All compounds were known, while 2-4 were isolated for the first time from the genus Carissa. Isolated compounds were screened for their cytotoxic via MTT assay and anti-inflammatory potential via luminol-enhanced chem-iluminescence assay. Compounds 3 and 4 showed potent activity against lung cancer cell line (NCI-H460), and 4 showed potent anti-inflammatory activity against reactive oxygen species production from human whole blood phagocytes. Compound 5 displayed good selective cytotoxicity against NCI-H460 and did not provoke cytotoxicity against normal cell line upto 250 µM. Compounds 3-5 were identified as potential anti-cancer drug leads.

Novel ursane-type triterpene from the fresh leaves of Carissa carandas and evaluation of cytotoxicity.

One novel ursolic acid derivative sabiracin 1 (11,25-epoxy-3ß-hydroxy-urs-12-en-28-oic acid) was isolated from the leaves of Carissa carandas, together with five known compounds para hydroxy benzaldehyde (2), ursolic acid (3), carissin (4), 22α-hydroxyursolic acid (5) and ß-sitosterol-3-O-ß-D-glucopyranoside (6). Compounds 2 and 5 were isolated for the first time from this genus. Structure elucidation was done by the help of spectroscopic techniques. Compounds 1-3, 5 and 6 were examined against oral cancer (CAL-27) and lung cancer (NCI-H460) cell lines. 6 showed good activity against oral cancer (IC50 18.69 µM), moderate activity against lung cancer (IC50 63.34 µM) and no cytotoxicity against normal cell lines.

Bilirubin binding affects the structure and function of alpha-2-macroglobulin.

Bilirubin is an endogenous antioxidant that is a metabolite of the heme in red blood cells (RBC). In blood, bilirubin is associated with albumin to form a water-soluble complex, known as unconjugated bilirubin. Alpha-2-macroglobulin (α2M) is a proteinase inhibitor found in the plasma of vertebrates. In the present study, we have investigated the interaction of photo-illuminated bilirubin with serum α2M using various biophysical and thermodynamic techniques. The binding of bilirubin to α2M leads to various functional and structural changes in α2M protein. The result of ultraviolet (UV) and fluorescence spectroscopy suggests that binding of bilirubin to α2M induces a conformational change in the secondary structure of protein which was corroborated by circular dichroism (CD) and Fourier-transform infrared spectroscopy (FT-IR). This binding leads to the conversion of ß-sheet into α-helical conformation and subsequently loss in protein activity. The thermodynamic parameters of bilirubin-α2M binding indicate that the binding is exothermic, and the reaction spontaneous. Our studies show that binding of bilirubin with α2M in the presence of light induces structural and functional modifications in the protein. Bilirubin possesses multiple biological activities, including immunomodulatory property which has not been extensively explored and which may be of interest for further study.

Understanding oxidants and antioxidants: Classical team with new players.

The free radical oxidants such as reactive oxygen species, reactive nitrogen species, and reactive sulfur species are produced inside cells through various metabolic processes. The body is equipped with an antioxidant defense system that guards against oxidative damage caused by these reactive oxidants and plays a major role in protecting cells from oxidative stress and damage. Antioxidants such as glutathione (GSH), thioredoxin, ascorbic acid and enzymes, for example, superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) counter the oxidative stress and protect lipids, proteins, and DNA. Antioxidants such as tocopherols, ascorbic acid, carotenoids, flavonoids, amino acids are also natural antioxidants present in foods. There is increasing demand and availability of designer foods fortified with antioxidants and probiotics that may be important in human health. The review article presents a brief overview of oxidants and antioxidant systems inside the human body including the role of probiotics and inflammation. PRACTICAL APPLICATIONS: Antioxidants such as GSH, thioredoxin, ascorbic acid, etc. and protective enzymes, for example, SOD, GPx, CAT, etc. counter oxidative stress and protect cellular biomolecules. Antioxidants such as tocopherols, ascorbic acid, carotenoids, flavonoids, amino acids, phospholipids, and sterols are natural antioxidants found in consumed foods. They play a major role in scavenging free radical and non-radical oxidants, and protect cells from oxidative stress and damage. The importance of antioxidants can be understood from the fact that oxidative damage is now associated with a variety of diseases including cancer, neurodegeneration, diabetes, etc. Several approaches to improve human health and achieve longevity use dietary antioxidants as formulation in diet and fortified foods. Antioxidants also maintain freshness and prolonging the shelf life of food products. The fortified or designer foods that are added with antioxidant nutrients and the use of microorganisms as probiotics are increasingly available in the market as health foods and supplements.

Influence of Ascorbic Acid on the Structure and Function of Alpha-2- macroglobulin: Investigations using Spectroscopic and Thermodynamic Techniques.

BACKGROUND: Ascorbic acid is a classic dietary antioxidant which plays an important role in the body of human beings. It is commonly found in various foods as well as taken as dietary supplement. OBJECTIVE: The plasma ascorbic acid concentration may range from low, as in chronic or acute oxidative stress to high if delivered intravenously during cancer treatment. Sheep alpha-2- macroglobulin (α2M), a human α2M homologue is a large tetrameric glycoprotein of 630 kDa with antiproteinase activity, found in sheep's blood. METHODS: In the present study, the interaction of ascorbic acid with alpha-2-macroglobulin was explored in the presence of visible light by utilizing various spectroscopic techniques and isothermal titration calorimetry (ITC). RESULTS: UV-vis and fluorescence spectroscopy suggests the formation of a complex between ascorbic acid and α2M apparent by increased absorbance and decreased fluorescence. Secondary structural changes in the α2M were investigated by CD and FT-IR spectroscopy. Our findings suggest the induction of subtle conformational changes in α2M induced by ascorbic acid. Thermodynamics signatures of ascorbic acid and α2M interaction indicate that the binding is an enthalpy-driven process. CONCLUSION: It is possible that ascorbic acid binds and compromises antiproteinase activity of α2M by inducing changes in the secondary structure of the protein.

Understanding the binding interaction between methotrexate and human alpha-2-macroglobulin: Multi-spectroscopic and computational investigation.

Methotrexate (MTX) is advised in the treatment of solid tumours, hematologic malignancies and autoimmune disorders. On reaching the circulation, 60% of MTX is bound to the proteins present in serum. Alpha-2-macroglobulin (α2M) is a plasma proteinase inhibitor with numerous functions such as binding, transportation and targeting of molecules. Our studies are the first attempt to investigate the binding interaction of pharmacologically important drug MTX, and highly abundant proteinase inhibitor- α2M. The protein functional activity assay shows 53% decrease in antiproteolytic potential of α2M upon drug interaction. The binding of MTX with α2M was studied by various biophysical methods. UV-visible absorption spectroscopy reveals hyperchromicity of α2M spectra upon drug binding. The intrinsic fluorescence spectra show quenching in fluorescence intensity of α2M and the mechanism of quenching was found to be static in nature. Far UV-CD spectra unveil slight alteration in secondary structure of α2M upon drug binding. Isothermal titration calorimetry (ITC) reveals the value of thermodynamic parameters and which affirms the binding process to be spontaneous and exothermic. Molecular docking illustrates that Asn173, Leu1298, Gly172, Lys1240, Gln1325, Ser1327, Glu913, Asn1139, Lys1236, Leu951 and Arg1297 were the key residues involved during interaction process. Molecular dynamics (MD) simulation studies suggest that MTX form a stable complex with α2M. Our study assumes importance from the fact that MTX is known to bind plasma proteins quite efficiently.

Inactivation of Alpha-2-Macroglobulin by Photo-Illuminated Gallic Acid.

Gallic acid is a naturally occurring plant polyphenol found in green tea and various fruits. Under certain conditions gallic acid exhibits pro-oxidant characteristics rather than its well known antioxidant property. In the present work, we explored the interaction of gallic acid with sheep alpha-2-macroglobulin (α2M) in the presence of light and determined the functional alteration and conformational modifications induced in α2M structure. α2M is a highly abundant homotetrameric antiproteinase glycoprotein having diverse functions. Our result suggests α2M loses almost 54% of its proteinase inhibitory activity after 2 h incubation with gallic acid in presence of light. The inactivation of α2M was due to photodynamic generation of superoxide radical and hydrogen peroxide by gallic acid. The UV/visible absorption spectra of α2M showed increase in absorbance due to complex formation with gallic acid. Intrinsic fluorescence study shows that α2M-gallic acid interaction leads to quenching of fluorescence intensity of α2M and the mechanism of quenching is found to be static in nature. Synchronous fluorescence measurements reveal that gallic acid interaction leads to change in the microenvironment around tryptophan residues of α2M. Moreover, Fourier transform infrared spectroscopy and circular dichroism spectra suggests perturbation in secondary structure of α2M. Binding parameters were investigated by spectroscopic as well as calorimetric measurements. Negative value of enthalpy change and Gibbs free energy confirms the binding process to be exothermic and spontaneous.

Deciphering the binding of dutasteride with human alpha-2-macroglobulin: Molecular docking and calorimetric approach.

Dutasteride is a pharmacologically important drug employed to treat prostate cancer. Alpha-2-macroglobulin (α2M) is the primary proteinase inhibitor and is abundant in vertebrate plasma. Previous studies have shown that α2M levels were down regulated in prostate cancer. Our results of functional assay shows 50% decrease in the antiproteolytic potential ofα2Mupon its interaction with dutasteride. Fluorescence quenching revealed that dutasteride binds with α2M via static mechanism, resulting in the formation of dutasteride-α2M complex. Synchronous fluorescence studies suggest alteration in the microenvironment around tryptophan residues. Changes in the UV-visible spectra hints at formation of complex between the drug and protein. Secondary structural perturbations in α2M are confirmed by circular dichroism studies. Molecular docking discloses the involvement of hydrogen bonding during the interaction process and suggests the site of interaction of dutasteride on α2M monomer as Asn173, Lys171, Asp1178, Lys1236, His1182, Lys1177, Ser1180 and Lys1240.Isothermal titration calorimetry affirms the binding process to be spontaneous and exothermic. The results of this study may potentially be important should it be shown that dutasteride interacts with α2M under physiological conditions.

Biophysical analysis of interaction between curcumin and alpha-2-macroglobulin.

Alpha-2-macroglobulin (α2M) is large glycoprotein present in the body fluids of vertebrates. It is an antiproteinase that inhibits a broad spectrum of proteases without the direct blockage of the protease active site. Curcumin, a yellow spice commonly used in India and several Asian countries, is reported to have anti-tumor and anti-inflammatory effects because of its antioxidant properties. In the present study, we have explored the interaction of curcumin with α2M using various technique such as antiproteinase activity assay, spectroscopy. Changes in the secondary structure of α2M following interaction with curcumin was investigated by CD and FT-IR spectroscopy. Thermodynamics of curcumin-α2M binding were also analyzed by isothermal titration calorimetry to identify the number of binding sites, changes in enthalpy, entropy and Gibbs free energy changes for this interaction. Thermodynamics parameters reveal that the binding is exothermic in nature. Our results suggest that the binding of curcumin with α2M induces a conformational change in the native form of protein that compromises its anti-proteinase activity. This exothermic and spontaneous interaction leads to alteration in the ß-sheet content of the protein leading to subtle changes in conformational status of the protein leading possibly to loss in the antiproteinase potential of the inhibitor.

Exploring the interaction of anti-androgen drug-bicalutamide with human alpha-2-macroglobulin: A biophysical investigation.

Bicalutamide (BCT), a drug used in the treatment of prostate cancer, antagonises the actions of androgens, at the receptor level, thereby inhibiting the growth of prostate tumours. Alpha-2-macroglobulin (α2M), a pan-proteinase inhibitor, inhibits proteinase, regardless of specificity and catalytic mechanism. α2M is deficient in patients of advanced prostate cancer with bone metastases. Our studies explored the interaction of BCT with α2M and analysed the BCT induced structural alteration to the α2M. The result suggests that BCT decreases the antiproteolytic potential and causes structural and functional change in human α2M. UV-visible absorption spectroscopy confirms the formation of α2M-BCT complex. Fluorescence analysis shows significant quenching in fluorescence intensity of α2M upon binding with BCT. Synchronous fluorescence result suggests the interaction of BCT with α2M changed the microenvironment around tyrosine residues. Secondary structure of α2M also undergoes a slight change upon complexation with the drug as evident by shift in negative ellipticity in far UV CD spectroscopy. FTIR results confirm the alteration in secondary structure of α2M upon drug interaction. Molecular docking studies show that BCT bind to a monomer of α2M primarily through hydrophobic force. Thermodynamics parameters were determined by isothermal titration calorimetry found that the binding was exothermic in nature.

Binding interaction of sheep alpha-2-macroglobulin and tannic acid: A spectroscopic and thermodynamic study.

Tannic acid is a polyphenol found in plant species commonly consumed by ruminants. It works as an important molecule in plant defense system to fight against environmental stressors. Tannic acid has number of effects on animals and humans. An attempt has been made to study the interaction of tannic acid with alpha-2-macroglobulin (α2M). α2M is a large tetrameric glycoprotein which function as a key serum anti-proteinase under physiological conditions. In the present study we explored the tannic acid-α2M interaction by number of spectroscopic techniques such as UV, fluorescence, CD and FTIR along with isothermal titration calorimetry. CD and FT-IR spectroscopy were mainly used to study the secondary structural change induced in the antiproteinase. Analysis of activity shows the antiproteolytic potential of protein was compromised. Data of UV spectroscopy shows formation of α2M-tannic acid complex. The thermodynamic signatures of this interaction reveals hydrogen bonding played a major role in the binding of α2M-tannic acid. Analysis of CD and FTIR results suggest a minor conformational change in α2M on tannic acid binding. Overall, tannic acid induces subtle conformation change in α2M structure resulting the loss of its proteinase inhibitory activity.

Insight into the interactions of proteinase inhibitor- alpha-2-macroglobulin with hypochlorite.

Hypochlorous acid (HOCl), an active bleaching agent is one of the major oxidant produced by neutrophils under physiological conditions. It is among one of the most potent reactive oxygen species (ROS) which causes oxidation of biomolecules. Treatment of proteins with hypochlorite results in direct oxidative damage to the protein. Alpha-2-macroglobulin (α2M) is a major proteinase inhibitor that can inhibit proteinase of any kind regardless of their specificity and catalytic mechanism. The proteinase-antiproteinase balance plays an important role in mediating inflammation associated tissue destruction. In this paper, we intend to study hypochlorite induced modifications in proteinase inhibitor- α2M via biophysical techniques such as absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD), fourier transform infrared spectrometry (FTIR) and isothermal titration calorimetry (ITC). It was found that hypochlorite decreases the anti-proteolytic potential and causes inactivation of sheep α2M. It also causes structural and functional change in sheep α2M as evident by UV-Visible absorption spectroscopy and fluorescence measurements. Change in secondary structure of α2M was confirmed by CD and FTIR. Thermodynamics parameters such as entropy change (ΔS), enthalpy change (ΔH), Gibbs free energy change (ΔG) and the number of binding sites (N) of α2M-HOCl binding in solutions were determined by ITC. Moreover, it was found that binding of HOCl with α2M was exothermic in nature.

Interaction of anti-cancer drug-cisplatin with major proteinase inhibitor-alpha-2-macroglobulin: Biophysical and thermodynamic analysis.

Alpha-2-macroglobulin is a multifunctional, highly abundant, plasma protein which reacts with a wide variety of molecules and drugs including cisplatin. Cisplatin is commonly used anticancer drug widely used for treatment of testicular, bladder, ovarian, head and neck, lung and cervical cancers. This study is designed to examine the interaction of cisplatin with human alpha-2-macroglobulin through various biophysical techniques and drug binding through molecular modeling. Cisplatin alters the function of alpha-2-macroglobulin and the thiolesters are most likely the reactive sites for cisplatin. Our result suggests that cisplatin decreases the antiproteolytic potential and causes structural and functional change in human alpha-2-macroglobulin as evident by absorption and fluorescence spectroscopy. Change in secondary structure of alpha-2-macroglobulin was confirmed by CD and FTIR. Thermodynamics parameters such as entropy (ΔS), enthalpy (ΔH) and Gibb's free energy changes (ΔG) along with number of binding sites (N) of alpha-2-macroglobulin-cisplatin binding in solutions were determined by isothermal titration calorimetry (ITC). It was found that binding of cisplatin with alpha-2-macroglobulin was exothermic in nature. The interaction of drug with alpha-2-macroglobulin in the plasma could lead to structural alterations in the conformational status of alpha-2-macroglobulin resulting in its functional inactivation.

Chemotherapeutic Drugs and Plasma Proteins: Exploring New Dimensions.

In the last few decades, advances in the cancer chemotherapy have been a marked success. A large number of anticancer drugs currently in use include drugs based on platinum complexes such as cisplatin, base analogues such as 5-florouracil and some ruthenium drugs. This review provides a bird's eye view of interaction of a number of clinically important drugs currently in use that show covalent or non-covalent interaction with serum proteins. Platinum drug-cisplatin interacts covalently and alters the function of the key plasma protease inhibitor molecule -alpha-2-macroglobulin and induces the conformational changes in the protein molecule and inactivates it. 5-fluorouracil (5-FU) is extensively metabolized and at physiological concentrations, is found to be associated with Human Serum Albumin (HSA). Similarly ruthenium compounds bind tightly to plasma proteins- serum albumin and serum transferrin, modifying their biological activity and increasing the toxicity of drug to cancer cells. Insight into varied anticancer drug- protein interaction will go a long way in understanding in totality of the mechanism of action of any anticancer drug and its possible effects/side effects.

Reactive oxygen species and anti-proteinases.

Reactive oxygen species (ROS) cause damage to macromolecules such as proteins, lipids and DNA and alters their structure and function. When generated outside the cell, ROS can induce damage to anti-proteinases. Anti-proteinases are proteins that are involved in the control and regulation of proteolytic enzymes. The damage caused to anti-proteinase barrier disturbs the proteinase-anti-proteinases balance and uncontrolled proteolysis at the site of injury promotes tissue damage. Studies have shown that ROS damages anti-proteinase shield of the body by inactivating key members such as alpha-2-macroglobulin, alpha-1-antitrypsin. Hypochlorous acid inactivates α-1-antitrypsin by oxidizing a critical reactive methionine residue. Superoxide and hypochlorous acid are physiological inactivators of alpha-2-macroglobulin. The damage to anti-proteinase barrier induced by ROS is a hallmark of diseases such as atherosclerosis, emphysema and rheumatoid arthritis. Thus, understanding the behaviour of ROS-induced damage to anti-proteinases may helps us in development of strategies that could control these inflammatory reactions and diseases.