Search Results (88)

The design and optimization of immobilized metal affinity chromatography (IMAC) media are crucial to enhancing the purification efficiency of recombinant proteins. In this study, the agarose-based microspheres are prepared by using a three-factorial Box–Behnken design followed by NTA-Ni²⁺ agarose-based microspheres (ABM) preparation by the “one-step” crosslinking of epichlorohydrin (ECH)–nitrilotriacetic acid (NTA) to efficiently couple the NTA ligand to the surface of the matrix. After preparation, various sophisticated techniques, including SEM, AFM, DSC, FTIR, and SDS-PAGE, were used to analyze the morphological structure, thermal stability, and chemical composition of NTA-Ni²⁺ ABM. The optimal conditions are identified as an emulsifier PP concentration of 8.12 wt%, a stirring speed of 1624.46 rpm, and an oil-phase temperature of 53.86 °C, giving a span value (Y) of 0.50684. SEM, AFM, DSC, and FTIR results showed that the fabricated NTA-Ni²⁺ ABM were structurally stable and had a uniform cross-linking network for up to 8 h of coupling reaction time. The performance results showed that the beads had a high binding capacity for His-tagged proteins (15.2 ± 0.8 mg/mL), and SDS-PAGE results demonstrated the efficient purification ability for target proteins. These findings provide the theoretical basis and a practical solution for the rational design and application of IMAC medium. Full article

Retinol-binding protein 4 (RBP4), an adipokine secreted by adipose tissues, has been implicated in metabolic inflammation and insulin resistance. Type 2 diabetes (T2D) is a recognized risk factor for osteoarthritis, with both conditions characterized by chronic low-grade inflammation, suggesting potential links between metabolic disorder and joint degeneration. This study aimed to investigate whether inflammatory and metabolic stresses regulate RBP4 expression and function in joint-related cells. Murine immature chondrocyte cells (iMACs) and the mouse AT805 teratocarcinoma cell line, clone 5, that differentiates into chondrogenic cells (ATDC5), were used as in vitro models for chondrocyte cells. Rbp4 mRNA expression increased during differentiation of iMACs, with 3.6- and 2.2-fold elevations observed on days 7 and 14, respectively (p < 0.01 vs. undifferentiated controls). Inflammatory stimulation with interleukin-6 (IL-6) significantly increased Rbp4 mRNA expression in ATDC5 cells (p < 0.05 vs. vehicle), along with elevated expression of catabolic and inflammatory mediators, including monocyte chemoattractant protein-1 (Mcp1), cyclooxygenase-2 (Cox2), and matrix metalloproteinase-3 (Mmp3) (p < 0.05 vs. vehicle). Pharmacological inhibition of RBP4 using fenretinide (FEN) attenuated chondrogenic differentiation marker expression, reduced glycosaminoglycan synthesis during chondrogenic differentiation, and mitigated high-glucose-induced catabolic responses, as indicated by reduced Mcp2 (p = 0.04) and Mmp13 (p = 0.01) expression in ATDC5 cells treated with FEN compared with cells treated with the vehicle under high-glucose conditions. Furthermore, in RAW 264.7 cells, a murine macrophage cell line commonly used as an in vitro model for osteoclastogenesis, FEN significantly reduced the expression of osteoclast differentiation markers, dendritic cell-specific transmembrane protein (DC-Stamp), nuclear factor of activated T-cells, cytoplasmic 1 (Nf-atc1), cathepsin k (Cath.k), and tartrate-resistant acid phosphatase (Trap) under osteoclastogenic conditions (p < 0.01 vs. vehicle). Collectively, these findings suggest that RBP4 functions as a metabolic–inflammatory mediator influencing both cartilage and bone-remodeling processes. This study reveals a previously unrecognized role of RBP4 in regulating osteoclast-associated pathways. Targeting RBP4 may, therefore, represent a promising therapeutic strategy for delaying or preventing osteoarthritis progression, particularly in metabolically compromised conditions. Full article

Protein phosphorylation is a crucial post-translational modification that regulates protein activity, cellular signaling, transcriptional regulation, and cell cycle control. However, the analysis of phosphoproteins in biological samples is often compromised by complex sample matrices and interference from high-abundance proteins. While the top-down phosphoproteomics strategy enables comprehensive analysis of post-translational modifications based on intact proteins, its requirement for higher protein purity due to low protein ionization efficiency poses stern challenges. Consequently, developing appropriate enrichment methods for phosphoproteins in practical samples becomes essential. Immobilized metal ion affinity chromatography (IMAC) represents a common strategy for phosphorylated protein separation and enrichment. Among metal ions, Ti⁴⁺ has gained widespread application as IMAC chelating ligands due to its capacity to form multiple coordination networks and its high selectivity for phosphorylated protein enrichment, leveraging the strong chelating ability of phosphate groups toward metal ions. This paper presents the design and preparation of a novel magnetic Ti-IMAC nanocomposite, MNP@MPTMS–VPA–Ti(IV). The material is modified with phosphate groups via facile thiol-ene click chemistry and then immobilizes Ti⁴⁺, enabling selective enrichment of intact phosphoproteins through IMAC affinity. The efficiency of enrichment was evaluated using subsequent matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for detection and analysis. This Ti-IMAC material-based magnetic solid-phase extraction (MSPE)-MALDI-TOF MS protocol has been successfully applied to enrich intact phosphoproteins in milk and eel mucus with high selectivity, sensitivity, and suitability. Full article

The metal-binding periplasmic protein CusF has been proposed as a bifunctional tag that enhances the solubility of recombinant proteins and enables purification using Cu affinity chromatography. However, evidence for its performance remains limited to a few model proteins. Here, we evaluated CusF as a solubility tag for two heterologous proteins: a putative poly(A)-polymerase from Enterococcus faecalis (Efa PAP) and the red fluorescent protein mCherry. The proteins were fused to CusF, expressed in E. coli BL21 (DE3) pLysS and Rosetta 2 (DE3) strains, and assessed for solubility and IMAC binding. Native Efa PAP was completely insoluble under all tested conditions, and fusion to CusF did not improve its solubility. Similarly, CusF–mCherry accumulated predominantly in the insoluble fraction, with only trace amounts detectable in soluble lysates. Soluble CusF–mCherry did not bind Cu²⁺-charged IMAC resin, while moderate binding to Ni²⁺-charged resin was attributable to the vector-encoded His tag rather than CusF. These results indicate that CusF does not universally enhance protein solubility and may not consistently bind Cu-based IMAC resin. Our findings expand empirical knowledge of solubility tag performance and emphasize the necessity of testing multiple tags to identify optimal strategies for recombinant protein production. Full article

Background and Objectives: This study aimed to evaluate the prognostic impact of baseline body composition measurements and changes in muscle and adipose tissue during treatment on overall survival (OS) in metastatic non-small cell lung cancer (NSCLC) patients treated with nivolumab. Materials and Methods: Eighty-eight metastatic NSCLC patients who were initiated on nivolumab between January 2022 and December 2024 were retrospectively analyzed. Body composition parameters were derived from baseline and 3-month ¹⁸F-FDG PET/CT scans at the L3 level, including psoas muscle index (PMI), skeletal muscle index (SMI), intramuscular adipose content (IMAC), and subcutaneous fat density (SFD). Treatment-related changes in body composition were evaluated, and survival analyses were performed using Kaplan–Meier estimates and Cox regression models. Results: Overall, 34.1% (n = 30) of patients were classified as sarcopenic. Median OS was significantly longer in non-sarcopenic patients (19 months vs. 5 months, p < 0.001). In univariate analysis, older age, higher comorbidity burden, liver metastasis, baseline sarcopenia, and adverse treatment-related changes in muscle and nutritional parameters were found to be associated with OS. In multivariate analysis, only unfavorable changes in skeletal muscle (ΔSMI; HR 3.39, p = 0.003) and subcutaneous fat radiodensity (ΔSFD; HR 2.45, p = 0.02) remained independent adverse prognostic factors. Baseline body composition parameters did not maintain their independence in multivariate models. Conclusions: Our study demonstrates that muscle loss or insufficient gain and unfavorable changes in subcutaneous fat radiodensity during nivolumab treatment more strongly predict overall survival compared to baseline measurements. These findings highlight the clinical importance of monitoring dynamic body composition throughout treatment, rather than static assessments, in NSCLC patients receiving immunotherapy. Full article

Fruit and coffee industries are responsible for huge quantities of agro-industrial wastes which is of great environmental and public health concern. Therefore, the aim of this work involves the use of such wastes for the production of β-D-glucan from basidiomycete strains which are powerful biological response modifiers in several clinical disorders. Experimental planning for optimization of several parameters was carried out by a full factorial of two levels of three factors for production of beta-glucans and basidiomycete species, where waste concentration and interaction between species and agro-industrial waste were the most important factors. The best conditions involved a basidiomycete strain of Lentinula edodes in a culture medium containing 400 g/L of waste coffee grounds which revealed the production of extracellular β-glucans (141.16 mg/L) at the 3rd day of fermentation. Intrinsic fluorescence properties of mushroom β-D-glucan were investigated by fluorescence spectroscopy as well as a fluorescence microtiter plate reader exhibiting emission peaks at 492 and 528 nm. Differential chromatographic behavior of β-D-glucan was investigated by immobilized metal affinity chromatography (IMAC) using epoxy-activated Sepharose 6B containing different chelating agents, spacer arms, and metal ions. One-step purification of β-D-glucan was devised using a column of epoxy-activated Sepharose 6B-IDA-Cu (II). FTIR analysis of several β-D-glucans from the chromatographic fractions was carried out to investigate their structural properties. Full article

Dermatomyositis (DM) is a prototypic idiopathic inflammatory myopathy in which characteristic skin disease frequently precedes or parallels muscle involvement and signals risks such as interstitial lung disease (ILD) and malignancy. This literature review integrates recent advances across dermatology, neuromuscular medicine, and immunology to refine diagnosis and management. We surveyed the literature from 2000 to 2025, prioritizing randomized trials, large cohorts, and translational studies that spanned classic and juvenile DM, amyopathic/hypomyopathic variants, and overlap phenotypes. Key insights include the diagnostic weight of pathognomonic cutaneous lesions with nailfold microangiopathy; the utility of myositis-specific autoantibodies for endotyping and risk (e.g., anti-TIF1-γ/anti-NXP2 and cancer, anti-MDA5 and rapidly progressive ILD); and the value of myxovirus-resistance protein A (MxA) immunohistochemistry and muscle MRI patterning (including distinctions from immune-mediated necrotizing myopathy) when enzymes are normal, or biopsies are treatment-modified. Management is anchored in early steroid-sparing immunosuppression tailored to phenotype, with evidence for IVIG in active DM and growing support for JAK inhibition, particularly in interferon-high or anti-MDA5 ILD, alongside selective use of calcineurin inhibitors and rituximab, with plasma exchange considered for refractory, rapidly progressive ILD. We highlight risk-stratified malignancy screening (IMACS 2023) and complications, including calcinosis, lipodystrophy, and chronic cutaneous damage. Skin-led recognition coupled with antibody-guided, phenotype-directed therapy and interdisciplinary care offers a pragmatic precision framework to improve outcomes and reduce long-term disability. Full article

CCCH zinc finger proteins play critical roles in plant growth, development and stress responses. Here, 56 CCCH genes were identified in Morus alba. These genes displayed wide variation in coding sequence (456–6318 bp) and protein length (151–2105 aa), with most proteins predicted to localize in the nucleus and a few in chloroplasts, the endoplasmic reticulum or cytoplasm. Chromosomal mapping showed uneven distribution across 14 chromosomes, with tandem clusters on chromosomes 1, 6 and 13. Phylogenetic analysis classified 53 MaC3Hs into 13 subfamilies, while three genes remained ungrouped. Synteny analysis revealed four segmental duplication events, suggesting segmental duplication as the major expansion mechanism, under purifying selection. Comparative collinearity showed higher conservation with Arabidopsis thaliana than with rice or maize. Promoter analysis identified 22 cis-acting elements, mainly related to phytohormones, followed by abiotic stress and developmental regulation. Expression profiling under drought stress revealed differential expression across tissues, with MaC3H33 showing strong induction (>200-fold in stems on day 6). Subcellular localization confirmed MaC3H33 is nuclear, and yeast assays indicated no self-activation. These findings provide comprehensive insights into the MaC3H gene family and lay a foundation for functional studies related to drought tolerance in mulberry. Full article

To express and purify staphylococcal enterotoxin M (SEM) using immobilized metal affinity chromatography (IMAC), a signal peptide-truncated (ΔNsp) wild-type SEM (SEM_WT) was N-terminally fused in pET-28a(+) to a polyhistidine tag (His_6×-) and thrombin cleavage site (TCS; LVPR↓GS), generating His_6×-TCS-ΔNspSEM_WT. Unexpectedly, 4 °C desalting reduced the fusion protein’s molecular weight by ~2.0 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal sequencing and mass spectrometry identified cleavage specifically at the arginine (R) and glycine (G) peptide bond (R–G bond) within the TCS motif. AlphaFold 3 revealed an exposed serine protease catalytic triad: histidine 172, serine 178, and aspartic acid 212 (H₁₇₂/S₁₇₈/D₂₁₂) in the β-grasp domain, suggesting intrinsic thrombin-like activity (TLA). Sequential IMAC and size-exclusion high-performance liquid chromatography (SE-HPLC) purification eliminated contaminant concerns, while chromogenic substrate S-2238 (S-2238) assays demonstrated increasing specific activity and purification fold, supporting intrinsic TLA. Critically, the mutation of serine at position 178 to alanine (His_6×-TCS-ΔNspSEM_S178A) abolished TLA but preserved the secondary/tertiary structure, confirming the activity’s origin within the wild-type construct. Molecular dynamics (MD) simulations probed the atomistic mechanism for specific R–G bond cleavage. This work establishes a foundation for understanding ΔNspSEM_WT’s TLA. Full article

Background and Objectives: The impact of sarcopenia and myosteatosis on renal transplantation (RT) outcomes has yet to be explained, certainly due to differences in assessment methods. The role of visceral adiposity is also not clearly defined. This retrospective study aimed to evaluate pretransplant body composition—including sarcopenia, myosteatosis, and visceral adiposity ratio (VSR)—using computed tomography (CT) and analyze their relationship with short- and long-term graft outcomes. Materials and Methods: A total of 94 patients who underwent RT between 2019 and 2023 and had pretransplant non-contrast abdominal CT scans were included. Skeletal muscle area (SMA) was assessed at the L3 vertebral level, including multiple muscle groups. Sarcopenia was defined by a low skeletal muscle index (SMI), while myosteatosis was defined by high intramuscular adipose tissue content (IMAC). Visceral adiposity was evaluated by the visceral-to-subcutaneous adipose tissue ratio (VSR). These parameters were compared with post-transplant outcomes. Results: The mean age was 42.69 ± 12.47 years, with 54.3% male patients. High IMAC was significantly associated with early graft failure (p = 0.026), delayed graft function (p = 0.005), death-censored graft failure (p = 0.036), and overall graft failure (p = 0.047). One-year mortality was also higher in the high IMAC group (14.8% vs. 0.0%, p = 0.012). SMI and VSR were not significantly associated with outcomes. Myosteatosis emerged as a significant risk factor in univariate analysis but was not independently predictive in multivariate analysis. Among the established risk factors identified in the study, recipient age was found to be a significant predictor for overall graft failure, donation type (cadaveric vs. living) for death-censored graft failure, and cold ischemia time for delayed graft function (OR: 1.068, 95% CI: 1.001–1.141, p = 0.049; OR: 147.7, 95% CI: 2.1—10,427.0, p = 0.021; OR: 1.003, 95% CI: 1.001–1.006, p = 0.023). Conclusions: Myosteatosis correlates with worse graft outcomes and higher mortality, but its independent prognostic value requires further investigation. Full article

Background: TNBC patients respond poorly to chemotherapy, leading to high mortality rates and a worsening prognosis. Here, we investigated the effect of M-I on TNBC tumor growth suppression and its potential mechanisms. Methods: Signaling pathways were analyzed to study the effect of M-I on TNBC cells (human MDA-MB-231 and mouse 4T1). We used orthotopic mouse models to examine the anti-tumor efficacy of M-I. Tumor volume and the status of tumor-associated macrophages (TAMs) were assessed by qRT-PCR or FACS analysis. Results: We found a significant dose- and time-dependent inhibition of TNBC cell proliferation following treatment with M-I. Cell cycle analysis revealed a shortened S phase in M-I-treated cells and downregulation of AURKA, PLK1, CDC25c, CDK1, and cyclinB1. Furthermore, M-I treatment reduced the expression of pSTAT3, cyclinD1, and c-Myc in TNBC cells. To evaluate the anti-tumor efficacy of M-I, we employed orthotopic TNBC mouse models and observed a significant reduction in tumor growth without measurable toxicity. Next, we analyzed RNA from control and M-I-treated tumors to further assess the status of TAMs and observed a significant decrease in M2-like macrophages in the M-I-treated group. Immortalized bone marrow-derived mouse macrophages (iMacs) exposed to conditioned media (CM) of TNBC cells with or without M-I treatment indicated that the M-I treated CM of TNBC cells significantly reduce the M2phenotype in iMacs. Mechanistically, we found that M-I specifically targets the IL-4/MAPK signaling axis to reduce immunosuppressive M2 macrophage polarization. Conclusions: Our study reveals a novel mechanism by which M-I inhibits TNBC cell proliferation by regulating intracellular signaling and altering TAMs in the tumor microenvironment and highlights its potential as a promising candidate for TNBC therapy. Full article

Protein phosphorylation is one of the most common and important post-translational modifications (PTMs) and is highly involved in various biological processes. Ideal adsorbents with high sensitivity and specificity toward phosphopeptides with large coverage are therefore essential for enrichment and mass spectroscopy-based phosphoproteomics analysis. In this study, a newly designed IMAC adsorbent composite was constructed on the graphene matrix coated with mesoporous silica. The outer functional 3D-network layer was prepared by free radical polymerization of the phosphonate-functionalized vinyl imidazolium salt monomer and subsequent metal immobilization. Due to its unique structural feature and high content of Ti⁴⁺ ions, the resulting phosphonate-immobilized adsorbent composite G@mSiO₂@PPFIL-Ti⁴⁺ exhibits excellent performance in phosphopeptide enrichment with a low detection limit (0.1 fmol, tryptic β-casein digest) and superior selectivity (molar ratio of 1:15,000, digest mixture of β-casein and bovine serum albumin). G@mSiO₂@PPFIL-Ti⁴⁺ displays high tolerance to loading and elution conditions and thus can be reused without a marked decrease in enrichment efficacy. The captured phosphopeptides can be released globally, and mono-/multi-phosphopeptides can be isolated stepwise by gradient elution. When applying this material to enrich phosphopeptides from human lung cell lysates, a total of 3268 unique phosphopeptides were identified, corresponding to 1293 phosphoproteins. Furthermore, 2698 phosphorylated peptides were found to be differentially expressed (p < 0.05) between human lung adenocarcinoma cells (SPC-A1) and human normal epithelial cells (Beas-2B), of which 1592 were upregulated and 1106 were downregulated in the cancer group. These results demonstrate the material’s superior enrichment efficiency in complex biological samples. Full article

Interferon signature is one of the key pathogenic pathways in idiopathic inflammatory myopathies (IIMs), particularly in dermatomyositis (DM). The aim of this study was to analyze Siglec-1, an interferon-inducible receptor, on different monocyte subsets in IIM subtypes and investigate its association with disease activity measures. Siglec-1 expression was measured by 8-color flow cytometry in 62 IIM patients and 10 healthy controls (HC). Disease activity was assessed using the International Myositis Assessment and Clinical Studies (IMACS) core set measures. Active DM patients exhibited significantly higher Siglec-1 mean fluorescence intensity (MFI) compared to inactive subgroups and HCs in every monocyte subset. Intermediate monocytes displayed the highest Siglec-1 expression across all groups and the strongest associations between disease activity markers. Siglec-1 expression on monocyte subsets was strongly associated with global, extramuscular global, constitutional, cutaneous, muscular, and gastrointestinal activity measures, but not with pulmonary, skeletal, and cardiac activities in the DM population. The best indicator of DM global disease activity among the examined biomarkers was Siglec-1 MFI on intermediate monocytes. Siglec-1 on intermediate monocytes correlates strongly with organ-specific clinical and biochemical markers of disease activity; therefore, it is a candidate biomarker for monitoring IIM disease activity. Siglec-1 could be useful in patient selection for interferon-targeted treatments. Full article

Transient gene expression (TGE) is commonly employed for protein production, but its reliance on plasmid transfection makes it challenging to scale up. In this paper, an alternative TGE method is presented, utilizing pseudoinfectious alphavirus as an expression vector. Pseudoinfectious viruses (PIV) and a replicable helper construct were derived from the genome of the Venezuelan equine encephalitis virus. The PIV carries a mutant capsid protein that prevents packaging into infectious particles, while the replicable helper encodes a wild-type capsid protein but lacks other viral structural proteins. Although PIV and the helper cannot independently spread infection, their combination results in increased titers in cell cultures, enabling easier scale-up of producing cultures. The PIV-driven production of a model protein outperforms that of alphavirus replicon vectors or simple plasmid vectors. Another described feature of the expression system is the modification to immobilized metal affinity chromatography (IMAC), allowing purification of His-tagged recombinant proteins from a conditioned medium in the presence of substances that can strip metal from the IMAC columns. The PIV-based expression system allows for the production of milligram quantities of recombinant proteins in static cultures, without the need for complex equipment such as bioreactors, and complies with regulatory requirements due to its distinction from common recombinant viruses. Full article

Protein purification is a crucial step for various downstream applications like drug development, antibody preparation, and structure determination. The constant pursuit is for methods that are more efficient and cost-effective. We propose a novel approach using an elastin-like polypeptide (ELP) as an aggregation core that serves as an anchor between the beads in a chromatography column. In this method, a chilled sample containing a [target protein type] fusion protein is loaded onto a pre-equilibrated IMAC (immobilized metal affinity chromatography) column with a low-salt buffer. The column is then washed with a warm buffer containing high salt to remove impurities. Here, the key step involves warming the column above the ELP’s transition temperature (Tt), which triggers its aggregation. This aggregation is expected to trap the target protein tightly between the beads. Subsequently, a harsh wash with high salt and high imidazole can be applied to remove even persistent contaminants, achieving high protein purity. Finally, the temperature is lowered, and a cold, low-salt buffer is introduced to reverse the aggregation and elute the purified target protein. This method has the potential to eliminate the need for sophisticated chromatography systems while still achieving high protein purity. Full article