A Method for in Vivo Quantification Of Cytokine IL-1β In The Rat Intrathecal Space

Universal CRISPR/Cas12a-associated aptasensor suitable for rapid detection of small proteins with a plate reader

With the discovery of the collateral cleavage activity, CRISPR/Cas12a has recently been identified as a key enabling approach in novel DNA biosensor development. Despite its remarkable success in nucleic acid detection, realizing a universal CRISPR/Cas biosensing system for non-nucleic acid targets remains challenging, particularly at extremely high sensitivity ranges for analyte concentrations lower than the pM level. DNA aptamers can be designed to bind to a range of specific target molecules, such as proteins, small molecules, and cells, with high affinity and specificity through configuration changes. Here, by harnessing its diverse analyte-binding ability and also redirecting the specific DNA-cutting activity of Cas12a to selected aptamers, a simple, sensitive, and universal biosensing platform has been established, termed CRISPR/Cas and aptamer-mediated extra-sensitive assay (CAMERA). With simple modifications to the aptamer and guiding RNA of Cas12a RNP, CAMERA demonstrated 100 fM sensitivity for targeting small proteins, such as IFN-γ and insulin, with less than 1.5-h detection time. Compared with the gold-standard ELISA, CAMERA achieved higher sensitivity and a shorter detection time while retaining ELISA's simple setup. By replacing the antibody with an aptamer, CAMERA also achieved improved thermal stability, allowing to eliminate the requirement for cold storage. CAMERA shows potential to be used as a replacement for conventional ELISA for a variety of diagnostics but with no significant changes for the experimental setup.

Intrathecal implantation surgical considerations in rodents; a review

Intrathecal access in humans is a routine clinical intervention. However, intrathecal access is limited to drug delivery purposes in rodents, and intrathecal implantation is not a common surgical practice. Preclinically, we have successfully adopted different intrathecal implantation surgical methods for different implant materials in rodents. However, employing the appropriate intrathecal implantation method is a challenging process for surgeons, which includes several steps such as preoperative evaluations and postoperative care. The aim of this review is to define and compare the major documented surgical approaches applicable for intrathecal implantation in rodents along with the associated side effects, as well as highlighting the critical preoperative and postoperative considerations. Overall, this review will provide surgeons with the principles of intrathecal implantation approaches applicable for different implant materials.

Cytokines: From Clinical Significance to Quantification

Cytokines are critical mediators that oversee and regulate immune and inflammatory responses via complex networks and serve as biomarkers for many diseases. Quantification of cytokines has significant value in both clinical medicine and biology as the levels provide insights into physiological and pathological processes and can be used to aid diagnosis and treatment. Cytokines and their clinical significance are introduced from the perspective of their pro- and anti-inflammatory effects. Factors affecting cytokines quantification in biological fluids, native levels in different body fluids, sample processing and storage conditions, sensitivity to freeze-thaw, and soluble cytokine receptors are discussed. In addition, recent advances in in vitro and in vivo assays, biosensors based on different signal outputs and intracellular to extracellular protein expression are summarized. Various quantification platforms for high-sensitivity and reliable measurement of cytokines in different scenarios are discussed, and commercially available cytokine assays are compared. A discussion of challenges in the development and advancement of technologies for cytokine quantification that aim to achieve real-time multiplex cytokine analysis for point-of-care situations applicable for both biomedical research and clinical practice are discussed.

Point-of-care detection of cytokines in cytokine storm management and beyond: Significance and challenges

Cytokines are signaling molecules between cells in immune system. Cytokine storm, due to the sudden acute increase in levels of pro‐inflammatory circulating cytokines, can result in disease severity and major‐organ damage. Thus, there is urgent need to develop rapid, sensitive, and specific methods for monitoring of cytokines in biology and medicine. Undoubtedly, point‐of‐care testing (POCT) will provide clinical significance in disease early diagnosis, management, and prevention. This review aims to summarize and discuss the latest technologies for detection of cytokines with a focus on POCT. The overview of diseases resulting from imbalanced cytokine levels, such as COVID‐19, sepsis and other cytokine release syndromes are presented. The clinical cut‐off levels of cytokine as biomarkers for different diseases are summarized. The challenges and perspectives on the development of cytokine POCT devices are also proposed and discussed. Cytokine POCT devices are expected to be the ongoing spotlight of disease management and prevention during COVID‐19 pandemic and also the post COVID‐19 pandemic era.

Science convergence applied to psychoneuroimmunology: The future of measurement and imaging

The future of psychoneuroimmunology requires breakthrough technology discoveries. These next generation technologies need to address the unique challenges that are raised by imaging and measuring the activity of the neuroimmune interface in health and disease. The complexity of this challenge is centred around the multidimensionality of the neuroimmune system. These include novel challenges of capturing potent and rare biological signals over long times and vast anatomical distances. Here is a summary of the outcomes of the investments made by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics which was presented as part of the PNIRSAsia-Pacific symposium at the 2019 International Brain Research Organization.

In vivo intrathecal IL-1β quantification in rats: Monitoring the molecular signals of neuropathic pain

BACKGROUND

Neuropathic pain, or pain after nerve injury, is a disorder with a significant reliance on the signalling of cytokines such as IL-1β. However, quantifying the cytokine release repeatedly over time in vivo is technically challenging.

AIM

To evaluate if changes in IL-1β are correlated with the presentation of mechanical allodynia over time, by repeatedly quantifying intrathecal IL-1β concentrations following chronic constriction injury of the sciatic nerve in rats. Also, to establish any possible correlation between biochemical spinal marker expression and the in vivo quantification of IL-1β. Finally, to assess the expression of the mature IL-1β in lumbar spinal cord samples.

METHOD

The Chronic Constriction Injury model (CCI) was used to initiate nerve injury in male Sprague Dawley rats and the generation of behavioural mechanical allodynia was quantified. Using an indwelling intrathecal catheter, a stainless steel (SS) wire biosensing device was repeatedly introduced to quantify intrathecal IL-1β concentrations at three timepoints of 0, 7, and 14 days post CCI. Fixed spinal cord samples (L4-L5), collected on day 14, were imaged for the expression of glial fibrillary acidic protein (GFAP, astrocytes) and ionized calcium binding adaptor molecule 1 (IBA1, microglia). Snap frozen spinal cord tissues (L4-L5) were also processed for western blot analysis.

RESULTS

Using the novel SS based biosensing device we established that CCI caused a significant increase in intrathecal IL-1β concentrations from day 0 to day 7 (p = 0.001) and to day 14 (p < 0.0001), while the sham group did not show any significant increase. We also further showed that the degree of mechanical allodynia correlated positively with the increase in the intrathecal concentration of IL-1β in the active CCI animals (p = 0.0007). While there was a significant increase in the ipsilateral GFAP expression in injured animals compared to sham animals (p = 0.03), we did not find any significant correlation between in vivo IL-1β concentration on days 7 and 14 and the area of dorsal horn GFAP or IBA1 positive structures on day 14. The result of western blot analysis of whole lumbar spinal cord revealed that there was no significant change (p = 0.7579) in IL-1β expression on day 14 in the CCI group compared to the sham group.

CONCLUSION

For the first time we have established that the SS based immunosensing platform technology can repeatedly sample the intrathecal space for bioactive peptides, such as IL-1β. Using this novel approach, we have been able to establish the correlation of the intrathecal concentration of IL-1β with the extent of mechanical allodynia, providing a molecular biomarker of the degree of the exaggerated pain state.