Infectious Complications of Lung Transplant for Coronavirus Disease 2019-Associated Lung Injury: A Single-Center Case-Control Cohort Study

BACKGROUND

Lung transplantation is one of the only options for patients with severe coronavirus disease 2019 (COVID-19)-associated lung injury (CALI). Studies on patients who received a lung transplant for CALI have, to date, not looked at the infectious outcomes.

METHODS

After institutional review board approval, a retrospective case-control cohort study, matched 1:1, collected data on patients who underwent lung transplantation for CALI (case) and for non-COVID-19 end-stage lung disease (control) between 1 June 2020 and 1 April 2022 at a large academic hospital in Chicago. We assessed infectious complications and other key outcomes pre-transplant and for 1 year post-transplant.

RESULTS

Among 78 patients (39 CALI and 39 matched control lung transplant patients), those in the CALI cohort were less likely to be vaccinated pre-transplant and were more likely to have diabetes, to be obese, to not be ambulatory, and to require pre-transplant extracorporeal membrane oxygenation and mechanical ventilation. Patients transplanted for CALI had higher rates of infection pre-transplant (66.7% vs 15.4% of patients in the control) and in the first 30 days post-transplant (43.6% vs 20.5%). Numbers and types of infection were similar in both groups at other time points. One-year mortality was similar for CALI and control groups (12.8% vs 10.3%, respectively).

CONCLUSIONS

Patients who received a lung transplant for CALI are more deconditioned with prolonged hospital stays and experience more infectious complications immediately pre- and post-transplant. Infections due to multidrug-resistant organisms are important contributors to morbidity and mortality in this population. Antimicrobial stewardship is urgently needed.

Plant optogenetics: Applications and perspectives

To understand cell biological processes, like signalling pathways, protein movements, or metabolic processes, precise tools for manipulation are desired. Optogenetics allows to control cellular processes by light and can be applied at a high temporal and spatial resolution. In the last three decades, various optogenetic applications have been developed for animal, fungal, and prokaryotic cells. However, using optogenetics in plants has been difficult due to biological and technical issues, like missing cofactors, the presence of endogenous photoreceptors, or the necessity of light for photosynthesis, which potentially activates optogenetic tools constitutively. Recently developed tools overcome these limitations, making the application of optogenetics feasible also in plants. Here, we highlight the most useful recent applications in plants and give a perspective for future optogenetic approaches in plants science.

Synaptic plasticity during systems memory consolidation

After learning, memory is initially encoded in the hippocampus but subsequently stabilized in other brain regions such as the cortex for long-lasting storage. This process is known as systems memory consolidation, and its cellular mechanism has long been a fundamental question. Synaptic plasticity is the major cellular mechanism underlying learning and memory, and is therefore considered a key function in the process of systems memory consolidation. Therefore, many studies have aimed to establish a causal link between synaptic plasticity in the brain and memory-associated behaviors. In this review, I discuss the various lines of research showing the function of synaptic plasticity, mainly in the hippocampus and cortex during memory consolidation.

A Photosensitized Singlet Oxygen (1O2) Toolbox for Bio-Organic Applications: Tailoring 1O2 Generation for DNA and Protein Labelling, Targeting and Biosensing

Singlet oxygen (¹O₂) is the excited state of ground, triplet state, molecular oxygen (O₂). Photosensitized ¹O₂ has been extensively studied as one of the reactive oxygen species (ROS), responsible for damage of cellular components (protein, DNA, lipids). On the other hand, its generation has been exploited in organic synthesis, as well as in photodynamic therapy for the treatment of various forms of cancer. The aim of this review is to highlight the versatility of ¹O_2, discussing the main bioorganic applications reported over the past decades, which rely on its production. After a brief introduction on the photosensitized production of ¹O₂, we will describe the main aspects involving the biologically relevant damage that can accompany an uncontrolled, aspecific generation of this ROS. We then discuss in more detail a series of biological applications featuring ¹O₂ generation, including protein and DNA labelling, cross-linking and biosensing. Finally, we will highlight the methodologies available to tailor ¹O₂ generation, in order to accomplish the proposed bioorganic transformations while avoiding, at the same time, collateral damage related to an untamed production of this reactive species.

Light-induced, spatiotemporal control of protein in the developing embryo of the sea urchin

Differential protein regulation is a critical biological process that regulates cellular activity and controls cell fate determination. It is especially important during early embryogenesis when post-transcriptional events predominate differential fate specification in many organisms. Light-induced approaches have been a powerful technology to interrogate protein functions with temporal and spatial precision, even at subcellular levels within a cell by controlling laser irradiation on the confocal microscope. However, application and efficacy of these tools need to be tested for each model system or for the cell type of interest because of the complex nature of each system. Here, we introduce two types of light-induced approaches to track and control proteins at a subcellular level in the developing embryo of the sea urchin. We found that the photoconvertible fluorescent protein Kaede is highly efficient to distinguish pre-existing and newly synthesized proteins with no apparent phototoxicity, even when interrogating proteins associated with the mitotic spindle. Further, chromophore-assisted light inactivation (CALI) using miniSOG successfully inactivated target proteins of interest in the vegetal cortex and selectively delayed or inhibited asymmetric cell division. Overall, these light-induced manipulations serve as important molecular tools to identify protein function for for subcellular interrogations in developing embryos.

Does Chemotherapy-Induced Liver Injury Impair Postoperative Outcomes After Laparoscopic Liver Resection for Colorectal Metastases?

BACKGROUND

Chemotherapy-associated liver injuries (CALI) have been associated with poor postoperative outcome after open liver resection. To date, no data concerning any correlation of CALI and laparoscopic liver resection (LLR) are available. In the present study, we evaluated the impact of CALI on short-term outcomes in patients undergoing LLR.

MATERIALS AND METHODS

All patients who underwent in our department LLR for colorectal liver metastases (CRLM) from 2000 to 2016 were retrospectively reviewed. Patients were divided in 4 groups according to their pathological histology. In group 1 patients had normal liver parenchyma. Group 2 included patients with steatosis and steatohepatitis. Patients with sinusoidal obstruction syndrome (SOS) and nodular regenerative hyperplasia (NRH) were allocated to group 3, whereas the remaining with fibrosis and cirrhosis, were assigned to group 4.

RESULTS

A total of 490 LLR for CRLM were included in the study. Perioperative details and morbidity did not differ significantly between the four groups. Subgroup analysis showed that NRH was associated with higher amount of blood loss (p = 0.043), overall (p = 0.021) and liver-specific morbidity (p = 0.039).

CONCLUSION

NRH is a severe form of CALI that may worsen the short-term outcomes of patients undergoing LLR for CRLM. However, the remaining forms of CALI do not have a significant impact on perioperative outcomes after LLR.

Genetically Encoded Photosensitizer for Destruction of Protein or Cell Function

There are several paths when excited molecules return to the ground state. In the case of fluorescent molecules, the dominant path is fluorescence emission that is greatly contributing to bioimaging. Meanwhile, photosensitizers transfer electron or energy from chromophore to the surrounding molecules, including molecular oxygen. Generated reactive oxygen species has potency to attack other molecules by oxidation. In this chapter, we introduce the chromophore-assisted light inactivation (CALI) method using a photosensitizer to inactivate proteins in a spatiotemporal manner and development of CALI tools, which is useful for investigation of protein functions and dynamics, by inactivation of the target molecules. Moreover, photosensitizers with high efficiency make it possible optogenetic control of cell ablation in living organisms and photodynamic therapy. Further development of photosensitizers with different excitation wavelengths will contribute to the investigation of multiple proteins or cell functions through inactivation in the different positions and timings.

The Tricellular Junction Protein Sidekick Regulates Vertex Dynamics to Promote Bicellular Junction Extension

Remodeling of cell-cell junctions drives cell intercalation that causes tissue movement during morphogenesis through the shortening and growth of bicellular junctions. The growth of new junctions is essential for continuing and then completing cellular dynamics and tissue shape sculpting; however, the mechanism underlying junction growth remains obscure. We investigated Drosophila genitalia rotation where continuous cell intercalation occurs to show that myosin II accumulating at the vertices of a new junction is required for the junction growth. This myosin II accumulation requires the adhesive transmembrane protein Sidekick (Sdk), which localizes to the adherens junctions (AJs) of tricellular contacts (tAJs). Sdk also localizes to and blocks the accumulation of E-Cadherin at newly formed growing junctions, which maintains the growth rate. We propose that Sdk facilitates tAJ movement by mediating myosin II-driven contraction and altering the adhesive properties at the tAJs, leading to cell-cell junction extension during persistent junction remodeling.

Green monomeric photosensitizing fluorescent protein for photo-inducible protein inactivation and cell ablation

BACKGROUND

Photosensitizing fluorescent proteins, which generate reactive oxygen species (ROS) upon light irradiation, are useful for spatiotemporal protein inactivation and cell ablation. They give us clues about protein function, intracellular signaling pathways and intercellular interactions. Since ROS generation of a photosensitizer is specifically controlled by certain excitation wavelengths, utilizing colour variants of photosensitizing protein would allow multi-spatiotemporal control of inactivation. To expand the colour palette of photosensitizing protein, here we developed SuperNova Green from its red predecessor, SuperNova.

RESULTS

SuperNova Green is able to produce ROS spatiotemporally upon blue light irradiation. Based on protein characterization, SuperNova Green produces insignificant amounts of singlet oxygen and predominantly produces superoxide and its derivatives. We utilized SuperNova Green to specifically inactivate the pleckstrin homology domain of phospholipase C-δ1 and to ablate cancer cells in vitro. As a proof of concept for multi-spatiotemporal control of inactivation, we demonstrate that SuperNova Green can be used with its red variant, SuperNova, to perform independent protein inactivation or cell ablation studies in a spatiotemporal manner by selective light irradiation.

CONCLUSION

Development of SuperNova Green has expanded the photosensitizing protein toolbox to optogenetically control protein inactivation and cell ablation.

Assays to Monitor Lysophagy

Lysophagy belongs to one of the many pathways cells activate in response to lysosomal damage. Damaged lysosomes attract glycan-binding galectins, become ubiquitinated, and are later on targeted for engulfment and degradation through lysophagy. Many triggers that are known to cause lysosomal membrane permeabilization have all been shown to induce lysophagy and can therefore be used to construct platforms for further molecular-level characterization of this process. In this chapter, we describe experimental parameters for triggering lysophagy through combined use of lysosome-specific dyes and light illumination. Within single cells, this optogenetic scheme allows easy manipulation on the amount of lysosomes to be impaired, the degree of damage desired, as well as when and where this should happen. On the other hand it can also be used to target all lysosomes within the entire cell population of a culture, allowing screening or bulk biochemical analyses to be carried out. The methodology will find use not only in monitoring lysophagy but also in probing lysosome damage responses in general.

The application of KillerRed for acute protein inactivation in living cells

Generating loss of protein function is a powerful investigatory tool particularly if carried out on a physiologically relevant timescale in a live-cell fluorescent imaging experiment. KillerRed mediated chromophore assisted light inactivation (CALI) uses genetic encoding for specificity and light for acute inactivation that can also be spatially restricted. This unit provides protocols for setting up and carrying out properly controlled KillerRed experiments during live-cell imaging of cultured cells.