Biology subjects

Stolla, M.

Publications and source records attributed to Stolla, M..

4 recordsLinked to original sources

bioRxiv2023

Cold temperature induces a TRPM8-independent calcium release from the endoplasmic reticulum in human platelets

Platelets are sensitive to temperature changes and akin to sensory neurons, are activated by a decrease in temperature. However, the molecular mechanism of this temperature-sensing ability is unknown. Yet, platelet activation by temperature could contribute to numerous clinical sequelae, most importantly to reduced quality of ex vivo-stored platelets for transfusion. In this interdisciplinary study, we present evidence for the expression of the temperature-sensitive ion channel transient receptor potential cation channel subfamily member 8 (TRPM8) in human platelets and precursor cells. We found the TRPM8 mRNA and protein in MEG-01 cells and platelets. Inhibition of TRPM8 prevented temperature-induced platelet activation and shape change. However, chemical agonists of TRPM8 did not seem to have an acute effect on platelets. When exposing platelets to below-normal body temperature, we detected a cytosolic calcium increase which was independent of TRPM8 but was completely dependent on the calcium release from the endoplasmic reticulum. Because of the high interindividual variability of TRPM8 expression, a population-based approach should be the focus of future studies. Our study suggests that the cold response of platelets is complex and TRPM8 appears to play a role in early temperature-induced activation of platelets, while other mechanisms likely contribute to later stages of temperature-mediated platelet response.

cell biology↗

bioRxiv2022

Deletion of 12-lipoxygenase normalizes platelet function after storage and transfusion in thrombocytopenic mice

ObjectivePlatelets for transfusion are stored for 5-7 days. During storage, platelets undergo numerous detrimental functional changes. In the current study, we sought to understand how genetic deletion of 12 -lipoxygenase (12-LOX) affects platelets during storage, before, and after transfusion. Approach and ResultsWe obtained platelets from wild-type (WT) and 12-LOX-/-mice and performed storage studies for 24 and 48 hours. Using LC-MS/MS-MRM, we showed that {omega}-3 and {omega}-6 fatty acids increased significantly in stored platelets from 12-LOX-/-mice, while oxylipins were significantly lower than in WT platelets. The circulation time of fresh 12-LOX-/-platelets was significantly shorter than that of fresh WT platelets, but no differences were observed after storage. Baseline IIb{beta}3 integrin activation was significantly lower before and after 24 hours of storage in 12-LOX-/-platelets than in WT platelets. Surprisingly, after transfusion, we observed more baseline IIb{beta}3 integrin activation in 12-LOX-/-platelets than in WT platelets. In line with this, transfusion of stored 12-LOX-/-platelets led to more frequent and significantly faster vessel occlusions than transfusion of stored WT platelets in a FeCl3-induced carotid artery injury model in thrombocytopenic mice. ConclusionDeleting 12-LOX improves the post-transfusion function of stored murine platelets. Pharmacologic inhibition of 12-LOX or dietary alterations of {omega}-3 and {omega}-6 PUFAs could significantly enhance human platelet quality and function after storage. Future studies must determine the feasibility and safety of 12-LOX inhibition in stored and transfused human platelets.

physiology↗

bioRxiv2022

Evaluating Stored Platelet Shape Change Using Imaging Flow Cytometry

Platelets are routinely stored at room temperature for 5-7 days before transfusion. Stored platelet quality is traditionally assessed by Kunickis morphology score. This method requires extensive training, experience, and is highly subjective. Moreover, the number of laboratories familiar with this technique is decreasing. Cold storage of platelets has recently regained interest because of potential advantages such as reduced bacterial growth and preserved function. However, platelets exposed to cold temperatures change uniformly from a discoid to a spherical shape, reducing the morphology score outcomes to a binary "spheres versus discs" during cooling. We developed a simpler, unbiased screening tool to measure temperature-induced platelet shape change using imaging flow cytometry. When reduced to two dimensions, spheres appear circular, while discs are detected on a spectrum from fusiform to circular. We defined circular events as having a transverse axis of > 0.8 of the longitudinal axis and fusiform events [≤] 0.8 of the longitudinal axis. We show that most EGTA-treated platelets and spherical beads are detected in the gate for circular events, while fresh platelets are found mainly in the gate for fusiform events. Using this assay, mouse and human platelets show a temperature and time-dependent, two-dimensional shape change from fusiform to circular, consistent with their three-dimensional change from discs to spheres. The method we describe here is a valuable tool for detecting shape change differences in response to agonists or temperature and will help screen for therapeutic measures to mitigate the cold-induced storage lesion. Plain language summaryO_ST_ABSWhat is the context?C_ST_ABSO_LIPlatelets for transfusion are currently stored for 5-7 days at room temperature, increasing the risk for bacterial growth C_LIO_LICold storage reduces the risk for bacterial growth but reduces circulation time C_LIO_LIStored platelet quality can be assessed by the light microscopy-based Morphology Score, first described in the 1970s C_LIO_LIDownsides of the Morphology Score include subjectivity, extensive training, and reduced availability in platelet laboratories. C_LI What is new?O_LIIn this study, we provide data showing that the Morphology score is reduced to a binary spheres versus discs response in cold-exposed platelets C_LIO_LIWe developed an imaging flow cytometry-based approach to quantify platelets response to cold based on the two-dimensional projection of the three-dimensional shapes, i.e., fusiform (discoid) versus circular (discoid and spherical) C_LIO_LIWe provide validation of this approach in mouse and human platelets C_LIO_LIWe provide evidence for increased temperature sensitivity in mouse platelets C_LI What is the impact?O_LIThis study provides an easy and unbiased tool for laboratories working on circumventing the cold-induced storage lesion or documenting spherical shape change in general C_LI

pathology↗

bioRxiv2021

Black Dots: Microcontact-Printed, Reference-Free Traction Force Microscopy

Measuring the traction forces produced by cells provides insight into their behavior and physiological function. Here, we developed a technique (dubbed black dots) that microcontact prints a fluorescent micropattern onto a flexible substrate to measure cellular traction forces without constraining cell shape or needing to detach the cells. To demonstrate our technique, we assessed human platelets, which can generate a large range of forces within a population. We find platelets that exert more force have more spread area, are more circular, and have more uniformly distributed F-actin filaments. As a result of the high yield of data obtainable by this technique, we were able to evaluate multivariate mixed effects models with interaction terms and conduct a clustering analysis to identify clusters within our data. These statistical techniques demonstrated a complex relationship between spread area, circularity, F-actin dispersion, and platelet force, including cooperative effects that significantly associate with platelet traction forces. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=79 SRC="FIGDIR/small/454500v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@1da5eeeorg.highwire.dtl.DTLVardef@18e939aorg.highwire.dtl.DTLVardef@17c7198org.highwire.dtl.DTLVardef@105c97c_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗