Construction and characterization of human embryonic kidney-(HEK)-293T cell overexpressing truncated α4 integrin

Exosomal Bupivacaine: Integrating Nerve Barrier Penetration Capability and Sustained Drug Release for Enhanced Potency in Peripheral Nerve Block and Reduced Toxicity

Peripherally injected local anesthetics exhibit limited ability to penetrate peripheral nerve barriers (PNBs), which limits their effectiveness in peripheral nerve block and increases the risk of adverse effects. In this work, we demonstrated that exosomes derived from Human Embryo Kidney (HEK) 293 cells can effectively traverse the perineurium, which is the rate-limiting barrier within PNBs that local anesthetics need to cross before acting on axons. Based on this finding, we use these exosomes as a carrier for bupivacaine (BUP), a local anesthetic commonly used in clinical settings. The in vitro assessments revealed that the prepared exosomal bupivacaine (BUP@EXO) achieves a BUP loading capacity of up to 82.33% and sustained release of BUP for over 30 days. In rats, a single peripheral injection of BUP@EXO, containing 0.75 mg of BUP, which is ineffective for BUP alone, induced a 2-hour sensory nerve blockade without significant motor impairments. Increasing the BUP dose in BUP@EXO to 2.5 mg, a highly toxic dose for BUP alone, extended the sensory nerve blockade to 12 hours without causing systemic cardiotoxicity and local neurotoxicity and myotoxicity.

Aptamers Targeting Hallmark Proteins of Neurodegeneration

Neurodegeneration is a progressive deterioration of neural structures leading to cognitive or motor impairment of the affected patient. There is still no effective therapy for any of the most common neurodegenerative diseases (NDs) such as Alzheimer's or Parkinson's disease. Although NDs exhibit distinct clinical characteristics, many are characterized by the accumulation of misfolded proteins or peptide fragments in the brain and/or spinal cord. The presence of similar inclusion bodies in patients with diverse NDs provides a rationale for developing therapies directed at overlapping disease mechanisms. A novel targeting strategy involves the use of aptamers for therapeutic development. Aptamers are short nucleic acid ligands able to recognize molecular targets with high specificity and high affinity. Despite the fact that several academic groups have shown that aptamers have the potential to be used in therapeutic and diagnostic applications, their clinical translation is still limited. In this study, we describe aptamers that have been developed against proteins relevant to NDs, including prion protein and amyloid beta (Aβ), cell surface receptors and other cytoplasmic proteins. This review also describes advances in the application of these aptamers in imaging, protein detection, and protein quantification, and it provides insights about their accelerated clinical use for disease diagnosis and therapy.

Generation of HBsAg DNA aptamer using modified cell-based SELEX strategy

Aptamers as potential alternatives for antibodies could be employed against hepatitis B surface antigen (HBsAg), the great hallmark and first serological marker in HBV, for further theragnostic applications. Therefore, isolation HBsAg specific aptamer was performed in this study with a modified Cell-SELEX method. HEK293T overexpressing HBsAg and HEK293T as target and control cells respectively, were incubated with single-stranded rounds of DNA library during six SELEX and Counter SELEX rounds. Here, we introduced the new modified Cell-SELEX using deoxyribonuclease I digestion to separate single stranded DNA aptamers against the HBsAg. Characterization and evaluation of selected sequences were performed using flow cytometry analysis. The results led to isolation of 15 different ssDNA clones in six rounds of selection which were categorized to four clusters based on common structural motifs. The evaluation of SELEX progress showed growth in aptamer affinity with increasing in the cycle number. Taken together, the application of modified cell-SELEX demonstrated the isolation of HBsAg-specific ssDNA aptamers with proper affinity. Modified cell-SELEX as an efficient method can shorten the selection procedure and increase the success rate while the benefits of cell-based SELEX will be retained. Selected aptamers could be applied in purification columns, diagnostic kits, and drug delivery system against HBV-related liver cancer.

An innovative cell selection approach in developing human cells overexpressing aspartyl/asparaginyl β-hydroxylase

Background and purpose:

Aspartyl/asparaginyl β-hydroxylase (ASPH) is abundantly expressed in malignant neoplastic cells. The establishment of a human cell line overexpressing ASPH could provide the native-like recombinant protein needed for developing theranostic probes. In the process of transfection, the obtained cells normally contain a range of cells expressing the different levels of the target of interest. In this paper, we report on our simple innovative approach in the selection of best-transfected cells with the highest expression of ASPH using subclone selection, quantitative real-time polymerase chain reaction, and gradual increment of hygromycin concentration.

Experimental approach:

To achieve this goal, human embryonic kidney (HEK 293T) cells were transfected with an ASPH-bearing pcDNA3.1/Hygro(+) vector. During antibiotic selection, single accumulations of the resistant cells were separately cultured and the ASPH mRNA levels of each flask were evaluated. The best subclones were treated with a gradually increasing amount of hygromycin. The ASPH protein expression of the obtained cells was finally evaluated using flow cytometry and immunocytochemistry.

Findings / Results:

The results showed that different selected subclones expressed different levels of ASPH. Furthermore, the gradual increment of hygromycin (up to 400mg/mL) improved the expression of ASPH. The best relative fold change in mRNA levels was 57.59 ± 4.11. Approximately 90.2% of HEK^ASPH cells overexpressed ASPH on their surface.

Conclusion and implications:

The experiments indicated that we have successfully constructed and evaluated a recombinant human cell line overexpressing ASPH on the surface. Moreover, our innovative selection approach provided an effective procedure for enriching highly expressing recombinant cells.

Aptamer-based approaches for in vitro molecular detection of cancer

Cancer is typically associated with abnormal production of various tumor-specific molecules known as tumor markers. Probing these markers by utilizing efficient approaches could be beneficial for cancer diagnosis. The current widely-used biorecognition probes, antibodies, suffer from some undeniable shortcomings. Fortunately, novel oligonucleotide-based molecular probes named aptamers are being emerged as alternative detection tools with distinctive advantages compared to antibodies. All of the existing strategies in cancer diagnostics, including those of in vitro detection, can potentially implement aptamers as the detecting moiety. Several studies have been performed in the field of in vitro cancer detection over the last decade. In order to direct future studies, it is necessary to comprehensively summarize and review the current status of the field. Most previous studies involve only a few cancer diagnostic strategies. Here, we thoroughly review recent significant advances on the applications of aptamer in various in vitro detection strategies. Furthermore, we will discuss the status of diagnostic aptamers in clinical trials.

Development of α4 integrin DNA aptamer as a potential therapeutic tool for multiple sclerosis

One of the most important molecules for multiple sclerosis pathogenesis is α4 integrin, which is responsible for autoreactive leukocytes migration into the brain. The monoclonal antibody, natalizumab, was introduced to market for blocking the extravasation of autoreactive leukocytes via inhibition of α4 integrin. However, the disadvantages of antibodies provided a suitable background for other agents to be replaced with antibodies. Considering the profound advantages of aptamers over antibodies, aptamer isolation against α4 integrin was intended in the current study. The α4 integrin-specific aptamers were selected using cell-systematic evolution of ligands by exponential enrichment (SELEX) method with human embryonic kidney (HEK)-293T overexpressing α4 integrin and HEK-293T as target and control cells, respectively. Evaluation of selected aptamer was performed through flow cytometric analysis. The selected clones were then sequenced and analyzed for any possible secondary structure and affinity. The results of this study led to isolation of 13 different single-stranded DNA clones in 11 rounds of selection which were categorized to three clusters based on common structural motifs and the equilibrium dissociation constant (K _d ) of the most stable structure was calculated. The evaluation of SELEX progress showed growth in aptamer affinity with increasing of the number of cycles. Taken together, the findings of this study demonstrated the isolation of α4-specific single-stranded DNA aptamers with suitable affinity for ligand, which can further be replaced with natalizumab.