Hepatocellular carcinoma (HCC) poses a serious threat to human health. Identifying diagnostic and therapeutic targets from plasma proteins is essential for early HCC detection and treatment. Large-scale plasma proteomics data and Mendelian randomization (MR) offer opportunities for this type of research. Proteomic data from protein quantitative trait loci were obtained from the UK Biobank Pharma Proteomics Project. Two-sample MR was used to evaluate the causal association between plasma protein levels and HCC. Sensitivity, directionality, and colocalization analyses were conducted to validate the causal associations identified by MR. Robustness was further tested through colocalization analysis. The single-cell dataset GSE166635 was used to assess the expression of genes corresponding to proteins identified via MR. Potential drugs targeting these proteins were evaluated using the DSigDB/DrugBank databases and molecular docking. Seven proteins with potential causal associations with HCC were identified: ASS1, B2M, FUOM, GABARAPL1, ST8SIA1, STOML2, and KRT8. Among these genes, ASS1, KRT8, and STOML2 presented the strongest effects in the colocalization analyses. In a single-cell liver cancer dataset, ASS1, KRT8, and STOML2 were expressed mainly in hepatic progenitor cells and malignant cells, with KRT8 predominantly found in hepatic progenitor cells and playing a role in the oncogenesis of malignant liver cells. Potential drugs targeting ASS1 include arginine, aspartic acid, and citrulline; for KRT8, ambroxol, diltiazem, and amikacin; and for STOML2, chlortetracycline, chlorzoxazone, and dirithromycin. This study identified several novel causal plasma proteins, providing new insights into the early diagnosis and treatment of HCC.

A screen-printed potentiometric sensor for the erythromycin macrolide antibiotic (ERY) that is affordable, highly selective, and sensitive is made, described, and used for drug monitoring. Two circular carbon dots with a diameter of 4 mm make up the sensor. Multiwalled carbon nanotubes and polyaniline (f-MWCNTs/PANi) nanocomposites are used to change one carbon spot, which is then used as an ion-to-electron transfer material. Ag/AgCl is applied to the other spot, which is then used as a reference electrode. A solid-state polyvinyl butyral (PVB) is placed onto the second carbon spot to work as a reference electrode, and an ERY molecularly imprinted drug polymer (MIP) is coated onto the f-MWCNTs/PANi-containing strip to serve as a drug identification sensing material. Chronopotentiometry (CP) is used to analyze the integrated sensor's performance characteristics. It is confirmed that f-MWCNTs/PANi has an increased impact on the potential stability as well as the sensing membrane's interfacial double-layer capacitance. At a detection limit of 9.6 ± 0.4 × 10-7 M, the developed sensor exhibits a Nernstian slope of 54.0 ± 0.5 mV per decade (R2 = 0.9994) over the linear range of 4.6 × 10-6 to 1.0 × 10-3 M. When exposed to different related substances such azithromycin, clarithromycin, dirithromycin, paracetamol, and ascorbic acid, the sensor exhibits excellent selectivity. For the direct potentiometric determination of ERY in some pharmaceutical formulations and in samples of spiked human urine, the assay method has been validated and shown to be adequate. The obtained recovery ranges from 93.0 ± 0.5 to 104.3 ± 0.7 of the nominal or spiked concentration, with a mean relative standard deviation of ±0.6%. Due to the near closeness of the responsive membrane and the liquid junction, the use of all-solid-state electrodes coupled with a planar disposable platform enables applications with a minimum sample volume. The effectiveness of the suggested sensor in a complex urine matrix points to its use in hospitals for quick overdose patient detection as well as for quality control/quality assurance tests in the pharmaceutical sector.

Macrolide antibiotics, which are effective antimicrobial agents, are intensively used in human and veterinary medicine, as well as in agriculture. Consequently, they are found all over the world as environmental pollutants, causing harm to sensitive ecological communities and provoking a selection of resistant forms. A novel azithromycin derivative, which was used as hapten conjugate, ensured the group immunorecognition of six major macrolide representatives (105-41%), namely erythromycin, erythromycin ethylsuccinate, clarithromycin, roxithromycin, azithromycin, and dirithromycin in a competitive immunoassay based on anti-clarithromycin antibodies. The heterologous hapten-based ELISA format resulted in a 5-fold increase in sensitivity, with an IC50 value of 0.04 ng/mL for erythromycin. In this study, we proposed an underexploited strategy in an immunoassay field to significantly improve the detectability of analytes in environmental samples. Unlike most approaches, it does not require special enhancers/amplifiers or additional concentration/extraction procedures; instead, it involves analyzing a larger volume of test samples. A gradual volume increase in the samples (from 0.025 to 10 mL) analyzed using a direct competitive ELISA, immunobeads, and immunofiltration assay formats based on the same reagents resulted in a significant improvement (more than 50-fold) in assay sensitivity and detection limit up to 5 and 1 pg/mL, respectively. The suitability of the test for detecting the macrolide contamination of natural water was confirmed by the recovery of macrolides from spiked blank samples (71.7-141.3%). During 2022-2023, a series of natural water samples from Lake Onega and its influents near Petrozavodsk were analyzed, using both the developed immunoassay and HPLC-MS/MS. The results revealed no contamination of macrolide antibiotic.

Due to the emergency and uncontrolled situation caused by the COVID-19 pandemic that arising in the entire world, it is necessary to choose available drugs that can inhibit or prevent the disease. Therefore, the repurposing of the commercial antibiotic, dirithromycin has been screened for the first time against fifteen receptors and compared to the azithromycin using a molecular docking approach to identify possible SARS-CoV-2 inhibitors. Our docking results showed that dirithromycin fit significantly in the Furin catalytic pocket having the lowest binding score (-9.9 Kcal/mol) with respect to azithromycin (-9.4 Kcal/mol) and can interact and block both Asp154 and Ser368 residues by Van der Walls interaction as well as bound to His194 and Ser368 residues via hydrogen bonds. Good results were also obtained with the Tmprss-2 receptor. A Molecular Dynamic simulation was assessed to confirm this interaction. Additionally, detailed receptor-ligand interactions with SARS-CoV-2 and pro-inflammatory mediators were investigated suggesting more target information with interesting results. The findings of this study are very efficient and provide a basis for the development of dirithromycin for clinical trial applications to be efficient in treating SARS-CoV-2 infections.

A lateral flow immunoassay (LFIA) using latex particles labeled with antibody to BSA-clarithromycin (CLA) was developed for the rapid simultaneous group determination of six macrolide antibiotics. Optimization of antigen spotting on the membrane and latex probe loading allowed improving visual detectability (vLOD) 100 times, which was 1, 1, 10, 10, 50, and 1000 ng/mL for CLA, roxithromycin, erythromycin, dirithromycin, azithromycin, and oleandomycin in buffer, respectively. The calculated limits of instrumental detection (cLOD) were respectively 0.12, 0.15, 1.4, 2.1, 2.4, and 3.3 ng/mL. To avoid a strong influence of breast milk of a very diverse and variable composition, a sample pretreatment is proposed. The six macrolides mentioned can be visually detected in breast milk after 20 min pretreatment at concentrations of 10-1000 ng/mL or instrumentally with cLOD of 4.0, 2.5, 30, 42, 42 and 180 ng/mL. The recovery rate from the spiked samples carried out using a strip scanner device ranged from 71 % to 110 %, and precision expressed as relative standard deviation was between 3-14 %. The described rapid on-site diagnostic assay format can be useful for monitoring the content of antibiotics in breast milk during macrolide treatment to ensure safe breastfeeding of infants.

Macrolides are one of the most successful and widely used classes of antibacterials, which kill or stop the growth of pathogenic bacteria by binding near the active site of the ribosome and interfering with protein synthesis. Dirithromycin is a derivative of the prototype macrolide erythromycin with additional hydrophobic side chain. In our recent study, we have discovered that the side chain of dirithromycin forms lone pair-π stacking interaction with the aromatic imidazole ring of the His69 residue in ribosomal protein uL4 of the Thermus thermophilus 70S ribosome. In the current work, we found that neither the presence of the side chain, nor the additional contact with the ribosome, improve the binding affinity of dirithromycin to the ribosome. Nevertheless, we found that dirithromycin is a more potent inhibitor of in vitro protein synthesis in comparison with its parent compound, erythromycin. Using high-resolution cryo-electron microscopy, we determined the structure of the dirithromycin bound to the translating Escherichia coli 70S ribosome, which suggests that the better inhibitory properties of the drug could be rationalized by the side chain of dirithromycin pointing into the lumen of the nascent peptide exit tunnel, where it can interfere with the normal passage of the growing polypeptide chain.

Although macrolides are known as excellent antibacterials, their medical use has been significantly limited due to the spread of bacterial drug resistance. Therefore, it is necessary to develop new potent macrolides to combat the emergence of drug-resistant pathogens. One of the key steps in rational drug design is the identification of chemical groups that mediate binding of the drug to its target and their subsequent derivatization to strengthen drug-target interactions. In the case of macrolides, a few groups are known to be important for drug binding to the ribosome, such as desosamine. Search for new chemical moieties that improve the interactions of a macrolide with the 70S ribosome might be of crucial importance for the invention of new macrolides. For this purpose, here we studied a classic macrolide, dirithromycin, which has an extended (2-methoxyethoxy)-methyl side chain attached to the C-9/C-11 atoms of the macrolactone ring that can account for strong binding of dirithromycin to the 70S ribosome. By solving the crystal structure of the 70S ribosome in complex with dirithromycin, we found that its side chain interacts with the wall of the nascent peptide exit tunnel in an idiosyncratic fashion: its side chain forms a lone pair-π stacking interaction with the aromatic imidazole ring of the His69 residue in ribosomal protein uL4. To our knowledge, the ability of this side chain to form a contact in the macrolide binding pocket has not been reported previously and potentially can open new avenues for further exploration by medicinal chemists developing next-generation macrolide antibiotics active against resistant pathogens.

The oriented attachment (OA) mechanism is promising for designing novel nanomaterials, yet an intensive understanding of the relationship between the crystal structure and attachment orientation is still lacking. In this work, we report layered hexagonal crystals of the pharmaceutical dirithromycin (DIR) containing multiple layers fabricated via a solvothermal method for a certain period of time at 40 °C. These elongated hexagonal crystals experience an OA that is preferentially on the face (001) of the initial crystals to assemble the final crystals into layered stacks. Through agreement with molecular modeling calculations, we predicted the final crystal growth morphology and confirmed the favored attachment surface based on the energy change ΔE following an OA event. These simulation results at the molecular level yielded good agreement with the crystal growth experiments. This study demonstrates the critical importance of combining experiments with a computational approach to understand the intrinsic molecular details of the OA growth mechanism of other compounds and to design nanomaterials with a desirable morphology and physical and chemical properties.

Dirithromycin antibiotic is a 14-membered lactone ring macrolide and is widely used in medicine to treat many different types of bacterial infections. In the present study, the possible genotoxicity of dirithromycin was evaluated in cultured human lymphocytes by using sister chromatid exchanges (SCEs), chromosome aberration (CA), and micronucleus (MN) tests and also cell proliferation kinetics such as mitotic index (MI), replication index (RI), and nuclear division index (NDI) were analyzed for cytotoxicity. Cell cultures were treated with four different concentrations of dirithromycin (37.75, 67.50, 125, and 250 µg/mL) for 24 and 48 h periods. Dirithromycin significantly induced SCE and MN frequency at all concentrations in both 24 and 48 h treated cells. In addition, CA level has been markedly increased in the cells treated with almost all concentrations of dirithromycin for 24 (except 37.75 µg/mL) and 48 h treatment periods as compared to control. However, MI, RI, and NDI values were not affected by the dirithromycin treatment (p > 0.05). The results of this study indicated that dirithromycin treatment caused genetic damage by increasing the level of cytogenetic endpoints, suggesting its genotoxic and mutagenic action on human lymphocytes in vitro.