Human Albumin Research Articles

Generating globin-like reactivities in [human serum albumin-FeII(heme)] complex through N-donor ligand addition

Human serum albumin (HSA) has a strong binding affinity for heme b, forming a complex in a 1:1 ratio with the co-factor ([HSA-FeIIIheme]). This system displays spectroscopic and functional properties comparable to globins when chemical derivatives mimicking them are incorporated into the protein matrix. The aim of this study is to generate globin-like systems using [HSA-FeIIIheme] as a protein template and binding N-donor ligands (imidazole, Im; and 1-methylimidazole, 1-MeIm) to construct artificial [HSA-Fe(heme)-(N-donor)] complexes. Their electronic structure and binding thermodynamics are investigated using UV–vis and (synchronous) fluorescence spectroscopies, while ligand-protein interactions are visualized using docking simulations. The imidazole derivatives have a strong affinity for [HSA-FeIIIheme] (K ~ 104–106), where the spontaneous binding of Im and 1-MeIm are dominated by entropic and enthalpic effects, respectively. The reduced form of the [HSA-Fe(heme)-(N-donor)] complexes demonstrate nitrite reductase (NiR) activity similar to that observed in globins, but with significant differences in their rates. [HSA-FeIIheme-(1-MeIm)] reduces nitrite ~4× faster than the Im analogue, and ~ 30× faster than myoglobin (Mb). The enhanced NiR activity of [HSA-FeIIheme-(1-MeIm)] is a cumulative effect of several factors including a slightly expanded and more optimal heme binding pocket, nearby residues as possible proton sources, and a H-bonding interaction between 1-MeIm and residues Arg160 and Lys181 that may have a long-distance influence on the heme π electron density.

Relationships between human serum albumin levels and septic shock, in-hospital, and out-of-hospital mortality in elderly patients with pneumonia in different BMI ranges

ObjectiveThis retrospective cohort identified the association of human serum albumin (HSA) with adverse outcomes (septic shock, in-hospital and out-of-hospital mortality) in elderly hospitalized patients who have community-acquired pneumonia (CAP) and specific body mass index (BMI).Materials and methodsThis research included hospitalized CAP individuals (≥ 60 years) and was conducted at a teaching hospital in western China. All the patients were categorized into three populations based on two BMI cutoff values (18.5 kg/m2 and 24 kg/m2). The data was acquired from medical records, local government mortality databases, and telephone interviews. Binomial logistic regression analysis was used to explore the associations between low HSA and septic shock and in-hospital mortality, and Cox regression analysis was used to explore the association between low HSA and out-of-hospital mortality.ResultsA total of 627 patients were included in the analysis of in-hospital death and septic shock, and 431 patients were included in the analysis of out-of-hospital death. The study showed that 120 elderly patients with CAP (19.14%) died in the hospital, while 141 patients (32.71%) died out of the hospital, and 93 patients (14.83%) developed septic shock. No differences in in-hospital and out-of-hospital mortality were observed for BMI values < 18.5 kg/m2 or BMI ≥ 24 kg/m2, regardless of whether HSA was ≥ 40 g/l or < 40 g/l. When 18.5 kg/m2 ≤ BMI < 24 kg/m2, patients with HSA < 40 g/l had both higher in-hospital and out-of-hospital mortality compared with those with HSA ≥ 40 g/l (in-hospital death: 26.13% vs. 11.46%, p < 0.001; out-of-hospital death: 46.15% vs. 19.17%, p < 0.001). No significant differences were observed in the incidence of septic shock between patients with HSA < 40 g/l and those with HSA ≥ 40 g/l either in the overall population or when the BMI values were divided according to the cutoff values of 18.5 kg/m2 and 24 kg/m2. After further logistic regression analysis and adjustment for potential confounders, the results showed that when 18.5 kg/m2 ≤ BMI < 24 kg/m2, elderly CAP patients with HSA < 40 g/l had a higher risk of in-hospital and out-of-hospital mortality compared with those with HSA ≥ 40 g/l (in-hospital death: HR = 1.964, 95%CI = 1.08–3.573; out-of-hospital death: HR = 2.841, 95%CI = 1.745–4.627).ConclusionsHSA levels can predict the risk of in-hospital and out-of-hospital mortality in elderly patients with CAP and normal BMI values. However, HSA cannot predict the risk of septic shock in elderly patients hospitalized with CAP, irrespective of their BMI classification.

Elucidating the binding dynamics and structural impacts of Pt(II) and Pd(II) complexes on human serum albumin: A comprehensive spectroscopic and computational study

The binding of drugs to plasma proteins, such as human serum albumin (HSA), encompasses two main functions: depot and transport, which are performed by these proteins. This binding has significant pharmacodynamic and pharmacokinetic consequences. 2-(furan-2-yl)-1H-imidazo[4,5-f][1,10]phenanthroline 1,2-diamino cyclohexane platinum (Pt(II)) or palladium (Pd(II)) complexes, have a similar structure. These new synthetic complexes have desirable anticancer activity, and the binding of these complexes with HSA was investigated. Spectroscopic and thermodynamic analyses indicate that the interactions between HSA and the complexes occur spontaneously with the static-dynamic quenching mechanism. However, the interactions are primarily driven by noncovalent forces such as hydrophobic interactions and π–π stacking, as evidenced by the positive enthalpy and entropy values associated with these complexes. In the circular dichroism (CD) results, HSA had fewer structural changes with the addition of the Pt(II) than the Pd(II) complex. Docking studies were performed at three Sudlow sites, I, II, and III, to identify the complex’s binding site on HSA. The reactive sites of HSA to Pt(II) and Pd(II) complexes mainly reside within its hydrophobic cavity in domain II (site II). Furthermore, molecular dynamics simulations showed low RMSD, Rg, and binding energy values during the 400 ns for the Pt(II) complex. The results suggest that the connection between the Pt(II) complex and HSA is reversible. The Pt(II) complex was a more desirable candidate than the Pd(II) complex. The results of the experimental methods are consistent with those of dynamic simulation and molecular docking methods, indicating that HSA is more stable in the presence of the Pt(II) complex.

A comprehensive investigation of the nano-[Cu2-(DIP)2-EA] effects on HSA through spectroscopic procedures and computer simulations

In this research, the toxicity of nano-[Cu2-(DIP)2-EA], a metal nano-complex consisting of ellagic acid and bathophenanthroline ligands, on human serum albumin (HSA) at a protein level was investigated. Molecular docking simulations and spectral analyses were conducted in a simulated physiological environment at pH 7.4 to explore the interaction of nano-[Cu2-(DIP)2-EA] with HSA. The results represented an increase in albumin absorption upon exposure to nano-[Cu2-(DIP)2-EA], demonstrating significant interaction between the two compounds. Steady-state and time-resolved fluorescence measurements pointed out that nano-[Cu2-(DIP)2-EA] induced static quenching of the albumin's intrinsic fluorescence with a high binding affinity of approximately 106 mol/L in a 1:1 interaction ratio. The thermodynamic variables clarified that binding of nano-[Cu2-(DIP)2-EA] to albumin occurs spontaneously and primarily driven by van der Waals interactions and H-bonds. The results of the computer simulations and the binding displacement experiments utilizing the site markers warfarin and ibuprofen revealed that nano-[Cu2-(DIP)2-EA] binds to site I within the subdomain IIA of albumin. Circular dichroism analysis elaborated that nano-[Cu2-(DIP)2-EA] slightly perturbed the microenvironment around of tryptophan residues and diminished the α-helix structure stability to a negligible amount.

Development of a Specifically Labeled 89Zr Antibody for the Noninvasive Imaging of Tumors Overexpressing B7-H3.

B7-H3 has emerged as a promising target and potential biomarker for diagnosing tumors, evaluating treatment efficacy, and determining patient prognosis. Hu4G4 is a recombinant humanized antibody that selectively targets the extracellular domain of human B7-H3. In this study, we describe the radiolabeling of hu4G4 with the positron emission tomography (PET) emitter radionuclide zirconium 89 (89Zr) and evaluate its potency as an immuno-PET tracer for B7-H3-targeted imaging by comparing it in vitro and in vivo to [89Zr]Zr-DFO-DS-5573a using various models. The radiolabeled compound, [89Zr]Zr-desferrioxamine-hu4G4 ([89Zr]Zr-DFO-hu4G4), demonstrated a high radiochemical purity (RCP) of greater than 99% and a specific activity of 74 MBq/mg following purification. Additionally, it maintained stability in human serum albumin (HSA) and acetate buffer, preserving over 90% of its RCP after 7 days. Three cell lines targeting human B7-H3(U87/CT26-CD276/GL261-CD276) were used. Flow cytometry analysis indicated that the B7-H3-positive cells (U87/CT26-CD276/GL261-CD276) had a higher B7-H3 protein level with no expression in the B7-H3-negative cells (CT26-wt/GL261-wt) (P < 0.001). Moreover, the cellular uptake was 45.71 ± 3.78% for [89Zr]Zr-DFO-hu4G4 in CT26-CD276 cells versus only 0.93 ± 0.47% in CT26-wt cells and 30.26 ± 0.70% when [89Zr]Zr-DFO-hu4G4 in CT26-CD276 cells were blocked with 100× 8H9. The cellular uptake of [89Zr]Zr-DFO-hu4G4 was akin to that observed with [89Zr]Zr-DFO-DS-5573a with no significant differences (45.71 ± 3.78 % vs 47.07 ± 0.86 %) in CT26-CD276 cells. Similarly, the CT26-CD276 mouse model demonstrated markedly low organ uptake and elevated tumor uptake 48 h after [89Zr]Zr-DFO-hu4G4 injection. PET/CT analysis showed that the tumor-to-muscle (T/M) ratios were substantially higher compared to other imaging groups: 27.65 ± 3.17 in CT26-CD276 mice versus 11.68 ± 4.19 in CT26-wt mice (P < 0.001) and 16.40 ± 0.78 when 100× 8H9 was used to block [89Zr]Zr-DFO-hu4G4 in CT26-CD276 mice (P < 0.01) at 48 h post-injection. Additionally, the tracer showed markedly high accumulation in the tumor region (22.57 ± 3.03% ID/g), comparable to the uptake of [89Zr]Zr-DFO-DS-5573a (24.76 ± 5.36% ID/g). A dosimetry estimation study revealed that the effective dose for [89Zr]Zr-DFO-hu4G4 was 2.96 × 10-01 mSv/MBq, which falls within the acceptable range for further research in nuclear medicine. Collectively, these results indicated that [89Zr]Zr-DFO-hu4G4 was successfully fabricated and applied in B7-H3-targeted tumor PET/CT imaging, which showed excellent imaging quality and tumor detection efficacy in tumor-bearing mice. It is a promising imaging agent for identifying tumors that overexpress B7-H3 for future clinical applications.

Technetium-99m radiolabeling of graphene quantum dots (GQDs) as a new probe for glioblastoma tumor imaging

Purpose Cancer diagnosis involves a multi-step process. Accurate identification of the tumor, staging and development of cancer cells is crucial for selecting optimal treatments to minimize disease recurrence. Quantum dots (QDs) represent an exciting class of fluorescent nanoprobes in molecular detection and targeted tumor imaging. Materials and methods In this study, graphene quantum dots (GQDs) were synthesized by pyrolysis of citric acid (CA) as a carbon precursor under high temperatures. The morphology of the obtained GQDs was first characterized using physical (TEM and DLS) and spectroscopic (fluorescence, FTIR and UV–Vis) methods. In the following,99mTc-labeled GQDs were prepared in the presence of SnCl2.2H2O as a reducing agent between 95 and 100 °C. The biodistribution and tumor targeting efficiency of radiolabeled GQDs as a novel agent for C6 glioma tumor scintigraphy in an animal model were evaluated. Furthermore, organ uptake, human serum albumin binding and tumor accumulation were measured. Results The TEM image of the prepared GQDs showed a relatively uniform size distribution in the range of diameter 6-9 nm and spherical shape. Radiolabeled GQDs showed a radiochemical yield of >97% (n = 3). Through incubation in human serum, almost 15% of 99mTc-labeled GQDs degraded after 6 h. The amount of uptake in xenograft models of glioma C6 rats was 1.10 ± 0.36% of injection dose per gram after 1 h. The kidneys, intestinal and glioma tumor sites were observed via scintigraphy imaging. Conclusion Our data suggest that 99mTc-labeled GQDs, as a new radiotracer, efficiently accumulate in the tumor site and could be included as a radiotracer for detecting glioma tumors.

Computational Study of Molecular Mechanism for the Involvement of Human Serum Albumin in the Renin–Angiotensin–Aldosterone System

Human serum albumin (HSA) is an endogenous inhibitor of angiotensin I-converting enzyme (ACE) and, thus, plays a key role in the renin–angiotensin–aldosterone system (RAAS). However, little is known about the mechanism of interaction between these proteins, and the structure of the HSA–ACE complex has not yet been obtained experimentally. The purpose of the presented work is to apply computer modeling methods to study the interaction of HSA with ACE in order to obtain preliminary details about the mechanism of their interaction. Ten possible HSA–ACE complexes were obtained by the procedure of macromolecular docking. Based on the number of steric and polar contacts between the proteins, three leading complexes were selected, the stabilities of which were then tested by molecular dynamics (MD) simulation. Based on the results of MD simulation, the two most probable conformations of the HSA–ACE complex were selected. The analysis of these conformations revealed that the processes of oxidation of the thiol group of Cys34 of HSA and the binding of albumin to ACE can reciprocally affect each other. Known point mutations in the albumin molecules Glu82Lys, Arg114Gly, Glu505Lys, Glu565Lys and Lys573Glu can also affect the interaction with ACE. According to the result of MD simulation, the known ACE mutations, albeit associated with various diseases, do not affect the HSA–ACE interaction. A comparative analysis was performed of the resulting HSA–ACE complexes with those obtained by AlphaFold 3 as well as with the crystal structure of the HSA and the neonatal Fc receptor (FcRn) complex. It was found that domains DI and DIII of albumin are involved in binding both ACE and FcRn. The obtained results of molecular modeling outline the direction for further study of the mechanisms of HSA–ACE interaction in vitro. Information about these mechanisms will help in the design and improvement of pharmacotherapy aimed at modulation of the physiological activity of ACE.

Plasmonic Nanotrenches with 1 nm Nanogaps for Surface-Enhanced Raman Scattering-Based Screening of His-Tagged Proteins.

This study represents a highly sensitive and selective approach to protein screening using surface-enhanced Raman scattering (SERS) facilitated by octahedral Au nanotrenches (OANTs). OANTs are a novel class of nanoparticles characterized by narrow, trench-like excavations indented into the eight facets of a Au octahedron. This unique configuration maximizes electromagnetic near-field focusing as the gap distance decreases to ∼1 nm. Owing to geometrical characteristics of the OANTs, near-field focusing can be maximized through the confinement and reflectance of light trapped within the trenches. We used Ni ions and molecular linkers to confer selective binding affinity for His-tagged proteins on the surfaces of the OANTs for SERS-based protein screening. Remarkably, SERS-based protein screening with the surface-modified OANTs yielded outstanding screening capabilities: 100% sensitivity and 100% selectivity in distinguishing His-tagged human serum albumin (HSA) from native HSA. This highlights the significantly enhanced protein screening capabilities achieved through the synergistic combination of SERS and the OANTs.

Bioactive potential of Algerian Citrullus colocynthis resin: Antioxidant and anti-inflammatory effects

This study explored the antioxidant, anti-inflammatory, and photoprotective properties of Citrullus colocynthis fruit resin from Algeria. A range of assays were conducted to assess these bioactivities, including DPPH• radical scavenging, total antioxidant capacity (TAC), ferric reducing antioxidant power (FRAP), ABTS+, haemolysis, and anti-inflammatory tests. The resin extract exhibited potent antioxidant activity, with an IC50 of 0.674 ± 0.016 mg/mL for DPPH scavenging, a TAC value of 0.064 ± 0.004 mg E A as/mg Ex, and an FRAP EC50 of 0.476 ± 0.09 mg/mL. The ABTS+ assay revealed an IC50 of 0.067 ± 0.009 mg/mL. In the haemolysis test, the IC50 was 0.413 ± 0.005 mg/mL, while albumin denaturation assays indicated significant anti-inflammatory effects, with values of 1.37 mg E Dc/mg Ex for human serum albumin and an IC50 of 0.472 ± 0.037 mg/mL for egg albumin. Photoprotective activity was also demonstrated, with a sun protection factor (SPF) of 14.6196. Phenolic compounds such as vanillic acid and naringin were identified in the extracts, contributing to the bioactive properties. These findings suggest that Citrullus colocynthis fruit resin is a promising source of bioactive compounds, with potential applications in pharmaceuticals, food, and cosmetics.

Interaction between modified magnetic nanoparticles and human albumin: Kinetics and isotherm studies and application in protein depletion

Magnetic nanoparticles modified with tetraethyl orthosilicate (Fe3O4@TEOS) and bovine serum albumin (Fe3O4@TEOS@BSA) were evaluated as sorbent in albumin depletion from human serum samples by magnetic dispersive solid phase extraction. Characterization studies were carried out by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy, zeta potential, and scanning electron microscopy. Both nanoparticles also showed high thermal stability and pH-dependent surface charges. The human serum albumin adsorption protocol was optimized using a central composite rotatable design. Nanoparticle mass, pH, and albumin concentration were the most influential variables. Avrami's fractional order and Freundlich isotherm models best fitted the data for human albumin adsorption kinetic and isotherm studies for Fe3O4@TEOS and Fe3O4@TEOS@BSA, and the maximum adsorption capacities were 11.93 and 14.89 mg g−1, respectively. The protein desorption was influenced by the pH of samples and eluent volume. Electrophoresis in a polyacrylamide gel containing sodium dodecyl sulfate showed different patterns of serum protein bands when consecutive depletions were performed. The Fe3O4@TEOS showed greater affinity for HSA and efficiency in depletion. The process was versatile, and the depleted albumin proportion could be controlled by the nanoparticle masses. The proposed method is a powerful sample preparation technique for rapid, reliable, and specific depletion of albumin.

Synthesis of a BODIPY-quinoline dyad probe and studies of its biophysical interactions with fibrinogen/HSA by spectral and computational methods

A new BODIPY-based quinoline dyad probe (Bdq) was synthesized and its binding affinity with fibrinogen (Fib) and human serum albumin (HSA) was examined using steady-state/three-dimensional (3D) fluorescence and UV–vis absorption as well as molecular docking method. Fluorescence titration assays indicated that protein intrinsic emission was quenched by Bdq with a combined (static and dynamic) mechanism to form a non-fluorescent complex. 3D spectra showed that the two proteins undergo conformational changes when they interact with Bdq. Based on Förster’s non-radiative energy transfer; r, binding distances were found as 3.64/3.47 nm for Fib/HSA. The negative values of both ΔH (−62.27 kJ/mol) and ΔS (−83.03 J/mol K) parameters pointed out van der Waals forces/hydrogen bonds with Fib and also positive values of both ΔH (240.0 kJ/mol) and ΔS (920.0 J/molK) showed hydrophobic interactions with HSA of Bdq. Molecular docking also gave consistent results supporting the experimental binding types.

A Multi-Spectroscopic and Molecular Docking Analysis of the Biophysical Interaction between Food Polyphenols, Urolithins, and Human Serum Albumin.

Secondary polyphenol metabolites, urolithins (UROs), have anti-oxidative, anti-inflammatory, and antidiabetic properties. Therefore, their biological activity relies on blood transport via human serum albumin (HSA) and tissue distribution. The main goal we set was to investigate the interaction between HSA and different URO (URO A, URO B, URO C, URO D, and glucuronidated URO A and B) using a combination of multi-spectroscopic instrumental and in silico approaches. The fluorescence spectroscopy revealed that URO can quench the naturally occurring fluorescence of HSA in a concentration-dependent manner. The HSA fluorescence was quenched by both a static and dynamic mechanism. The results showed that free UROs bind to HSA with higher affinity than their conjugated forms. CD spectroscopy and FTIR revealed that the alpha-helical structure of HSA is preserved. The calculated Gibbs free energy change indicates that the URO-HSA complex forms spontaneously. There is a single binding site on the HSA surface. The molecular docking results indicated that unconjugated Uro binds to Sudlow I, while their conjugation affects this binding site, so in the conjugated form, they bind to the cleft. Docking experiments indicate that all UROs are capable of binding to both thyroxine recognition sites of ligand-bound HSA proteins. Examining interactions under the following conditions (298 K, 303 K, and 310 K, pH 7.4) is of great importance for determining the pharmacokinetics of these bioactive compounds, as the obtained results can be used as a basis for modulating the potential dosing regimen.

Research progress on albumin therapy for hepatic encephalopathy

Hepatic encephalopathy (HE) is one of the severe complications of decompensated stage cirrhosis that causes cerebral dysfunction due to hepatic insufficiency and/or portosystemic shunts, and it usually manifests as a wide spectrum of neurological or psychiatric abnormalities ranging from subclinical alterations to coma. The pathogenesis of HE is complex, although ammonia toxicity, oxidative stress, inflammation, intestinal dysbiosis, and others among them mainly play an important role. The treatment for HE lacks specific drugs, and the current available drugs include non-absorbable disaccharides (lactulose), antibiotics (rifaximin), and other therapies (oral branched-chain amino acids, intravenous injection of L-ornithine-L-aspartic acid, probiotics). Recent research has shown that human albumin is a safe and effective treatment for HE, improving not only cognitive function but also enhancing patients' quality of life.

Turbocharging protein binding site prediction with geometric attention, inter-resolution transfer learning, and homology-based augmentation

BackgroundLocating small molecule binding sites in target proteins, in the resolution of either pocket or residue, is critical in many drug-discovery scenarios. Since it is not always easy to find such binding sites using conventional methods, different deep learning methods to predict binding sites out of protein structures have been developed in recent years. The existing deep learning based methods have several limitations, including (1) the inefficiency of the CNN-only architecture, (2) loss of information due to excessive post-processing, and (3) the under-utilization of available data sources.MethodsWe present a new model architecture and training method that resolves the aforementioned problems. First, by layering geometric self-attention units on top of residue-level 3D CNN outputs, our model overcomes the problems of CNN-only architectures. Second, by configuring the fundamental units of computation as residues and pockets instead of voxels, our method reduced the information loss from post-processing. Lastly, by employing inter-resolution transfer learning and homology-based augmentation, our method maximizes the utilization of available data sources to a significant extent.ResultsThe proposed method significantly outperformed all state-of-the-art baselines regarding both resolutions—pocket and residue. An ablation study demonstrated the indispensability of our proposed architecture, as well as transfer learning and homology-based augmentation, for achieving optimal performance. We further scrutinized our model’s performance through a case study involving human serum albumin, which demonstrated our model’s superior capability in identifying multiple binding sites of the protein, outperforming the existing methods.ConclusionsWe believe that our contribution to the literature is twofold. Firstly, we introduce a novel computational method for binding site prediction with practical applications, substantiated by its strong performance across diverse benchmarks and case studies. Secondly, the innovative aspects in our method— specifically, the design of the model architecture, inter-resolution transfer learning, and homology-based augmentation—would serve as useful components for future work.

Evaluation of Maternal Ischemia-Modified Albumin Levels during Pregnancy and Their Effect on Fetal Birth Weight.

Background and Objectives: The purpose of this study is to evaluate the impact of maternal ischemia-modified albumin (IMA) levels on pregnancy-related complications, fetal growth, and development over time. Materials and Methods: The prospective longitudinal and single-center study included 43 pregnant women ages 18 to 43. Routine pregnancy follow-up began at the first antenatal examination for all pregnant women before 14 weeks gestation, with IMA levels measured during the first, second, and third trimesters. The albumin cobalt binding test was used to determine the amount of ischemia-modified albumin (IMA). The patients' medical, sociodemographic, and nutritional data were analyzed. The primary outcome was to investigate how changes in maternal ischemia affected albumin levels during pregnancy and the relationship between these changes and newborn weight. Results: This study included 43 cases with a mean age of 28.5 ± 5.2 years and a mean gestation period of 39.2 ± 1.3 weeks. The mean IMA levels for cases in the first trimester, second trimester, and third trimester were 0.53 ± 0.06, 0.64 ± 0.11, and 0.64 ± 0.06, respectively. The second and third trimesters showed significantly higher levels of ischemia-modified albumin (IMA) than the first trimester (p < 0.01). There was no statistically significant difference in IMA levels between the second and third trimesters (p = 1.000; p > 0.05). There was no statistically significant correlation between fetal birth and percentage changes in IMA measurements between the first and second trimesters, the first and third trimesters, or the second and third trimesters (p > 0.05). Conclusions: Our study determined that maternal ischemia-modified albumin levels during pregnancy did not correlate with fetal birth weight. Our findings revealed that age, sociodemographic changes, BMI, weight gain, and pregnancy complications had no effect on the change in IMA levels during pregnancy. We believe that this result will serve as a benchmark for future studies on IMA levels during pregnancy.

An in vitro and machine learning framework for quantifying serum albumin binding of per- and polyfluoroalkyl substances

Abstract Per- and polyfluoroalkyl substances (PFAS) are a diverse class of anthropogenic chemicals; many are persistent, bioaccumulative, and mobile in the environment. Worldwide, PFAS bioaccumulation causes serious adverse health impacts, yet the physiochemical determinants of bioaccumulation and toxicity for most PFAS are not well understood, largely due to experimental data deficiencies. As most PFAS are proteinophilic, protein binding is a critical parameter for predicting PFAS bioaccumulation and toxicity. Among these proteins, human serum albumin (HSA) is the predominant blood transport protein for many PFAS. We previously demonstrated the utility of an in vitro differential scanning fluorimetry assay for determining relative HSA binding affinities for 24 PFAS. Here, we report HSA affinities for 65 structurally diverse PFAS from 20 chemical classes. We leverage these experimental data, and chemical/molecular descriptors of PFAS, to build 7 machine learning classifier algorithms and 9 regression algorithms, and evaluate their performance to identify the best predictive binding models. Evaluation of model accuracy revealed that the top performing classifier model, logistic regression, had an AUROC statistic of 0.936. The top performing regression model, support vector regression, had an R2 of 0.854. These top performing models were then used to predict HSA-PFAS binding for chemicals in the EPAPFASINV list of 430 PFAS. These developed in vitro and in silico methodologies represent a high-throughput framework for predicting protein-PFAS binding based on empirical data, and generate directly comparable binding data of potential use in predictive modeling of PFAS bioaccumulation and other toxicokinetic endpoints.

Theoretical Study of the Effects of Different Coordination Atoms (O/S/N) on Crystal Structure, Stability, and Protein/DNA Binding of Ni(II) Complexes with Pyridoxal-Semi, Thiosemi, and Isothiosemicarbazone Ligand Systems

Nickel transition metal complexes have shown various biological activities that depend on the ligands and geometry. In this contribution, six Ni(II) nitrate complexes with pyridoxal-semi, thiosemi, and isothiosemicarbazone ligands were examined using theoretical chemistry methods. The structures of three previously reported complexes ([Ni(PLSC)(H2O)3]∙2NO3−, [Ni(PLTSC)2] ∙2NO3−∙H2O, and [Ni(PLITSC)(H2O)3]∙2NO3−) were investigated based on Hirshfeld surface analysis, and the most important stabilization interactions in the crystal structures were outlined. These structures were optimized at the B3LYP/6-311++G(d,p)(H,C,N,O,(S))/LanL2DZ(Ni) level of theory, and the applicability was checked by comparing theoretical and experimental bond lengths and angles. The same level of theory was applied for the optimization of three additional structures, ([Ni(PLSC)2]2+, [Ni(PLTSC)(H2O)3]2+, and [Ni(PLITSC)2]2+). The interactions between selected ligands and Ni(II) were examined using the Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) approaches. Particular emphasis was placed on interactions between oxygen, sulfur, and nitrogen donor atoms and Ni(II). Human Serum Albumin (HSA) and the DNA-binding properties of these complex cations were assessed using molecular docking simulations. The presence of water molecules and various substituents in the thermodynamics of the processes was demonstrated. The results showed significant effects of structural parameters on the stability and reactivity towards important biomolecules.

Inhibition of Insulin-like Growth Factor 1 Receptor/Insulin Receptor Signaling by Small-Molecule Inhibitor BMS-754807 Leads to Improved Survival in Experimental Esophageal Adenocarcinoma.

The insulin-like growth factor-1 (IGF-1) and insulin axes are upregulated in obesity and obesity-associated esophageal adenocarcinoma (EAC). Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is a contemporary nanotechnology-based paclitaxel (PT) bound to human albumin, ensuring its solubility in water rather than a toxic solvent. Here, we examined the benefits of inhibiting insulin-like growth factor-1 receptor/insulin receptor (IGF-1/IR) signaling and the enhancement of nab-paclitaxel effects by inclusion of the small-molecule inhibitor BMS-754807 using both in vitro and in vivo models of EAC. Using multiple EAC cell lines, BMS-754807 and nab-paclitaxel were evaluated as mono and combination therapies for in vitro effects on cell proliferation, cell death, and cell movement. We then analyzed the in vivo anticancer potency with survival improvement with BMS-754807 and nab-paclitaxel mono and combination therapies. BMS-754807 monotherapy suppressed in vitro cell proliferation and wound healing while increasing apoptosis. BMS-754807, when combined with nab-paclitaxel, enhanced those effects on the inhibition of cell proliferation, increment in cell apoptosis, and inhibition of wound healing. BMS-754807 with nab-paclitaxel produced substantially greater antitumor effects by increasing in vivo apoptosis, leading to increased mice survival compared to those of BMS-754807 or nab-paclitaxel monotherapy. Our outcomes support the use of BMS-754807, alone and in combination with nab-paclitaxel, as an efficient and innovative treatment choice for EAC.

Investigation of the crystal structure, spectral properties, and interactions of N-(R-nitrophenylsulfonamido)benzoic acids with human serum albumin

This study introduced the synthesis of two novel compounds in the N-(R-nitrophenylsulfonamido)benzoic acids (NO2-SBA), designated as HL6 and HL8. Detailed structural information for HL6 and HL8 was acquired through the employment of various characterization techniques such as single-crystal and powder X-ray diffraction, FT-IR spectroscopy, 1H and 13C NMR spectroscopy, and elemental analysis. X-ray diffraction and Hirshfield surface analysis provides a comparative analysis of hydrogen bonding in HL6·H2O and HL8, revealing significant differences in their interaction patterns and resulting crystal structures. Although both molecules possess the same number of hydrogen bond donors and acceptors, the nature of these interactions and their orientations lead to distinct packing arrangements. In HL6·H₂O, the presence of water molecules introduces additional hydrogen bonding possibilities, which are absent in HL8, significantly affecting the overall structure. Additionally, interactions of all nine compounds in the NO2-SBA series [categorized as o-ABA: HL1–HL3, m-ABA: HL4–HL6, and p-ABA: HL7–HL9] with human serum albumin (HSA) were investigated to understand how structural characteristics influence binding mechanisms and affinity. Fluorescence spectroscopy was employed to further examine these interactions, providing a better understanding of their pharmacological properties. The compounds exhibited moderate affinity to HSA, with the o-ABA series displaying a binding constant (Kb) ten times stronger than the other series, underscoring the significant role of the N,R groups in binding interactions.

The Counterion (SO42− and NO3−) Effect on Crystallographic, Quantum-Chemical, Protein-, and DNA-Binding Properties of Two Novel Copper(II)–Pyridoxal-Aminoguanidine Complexes

New Cu(II) complexes with pyridoxal-aminoguanidine (PLAG) ligands and different counterions (SO42− and NO3−) were prepared and their crystal structures were solved by the X-ray crystallography. The geometries of the obtained complexes significantly depended on the counterions, leading to the square-pyramidal structure of [Cu(PLAG)NO3H2O]NO3 (complex 1) and square-planar structure of [Cu(PLAG)H2O]SO4 (complex 2). The intermolecular interactions were examined using the Hirshfeld surface analysis. The theoretical structures of these complexes were obtained by optimization at the B3LYP/6-311++G(d,p)(H,C,N,O,S)/LanL2DZ(Cu) level of theory. The Quantum Theory of Atoms in Molecules (QTAIM) was applied to assess the strength and type of the intramolecular interactions and the overall stability of the structures. The interactions between the complexes and transport proteins (human serum albumin (HSA)) and calf thymus DNA (CT-DNA) were examined by spectrofluorometric/spectrophotometric titration and molecular docking. The binding mechanism to DNA was assessed by potassium iodide quenching experiments. The importance of counterions for binding was shown by comparing the experimental and theoretical results and the examination of binding at the molecular level.