Biology subjects

Amadeo, M. B.

Publications and source records attributed to Amadeo, M. B..

3 recordsLinked to original sources

bioRxiv2020

Cyclic-di-GMP induces STING-dependent ILC2 to ILC1 shift during innate type 2 lung inflammation

Type 2 inflammation is found in most forms of asthma, which may co-exist with recurrent viral infections, bacterial colonization, and host cell death. These processes drive the accumulation of intracellular cyclic-di-nucleotides such as cyclic-di-GMP (CDG). Group 2 innate lymphoid cells (ILC2s) are critical drivers of type 2 lung inflammation during fungal allergen exposure in mice; however, it is unclear how CDG regulates lung ILC responses during lung inflammation. Here, we show that CDG induced early airway type 1 interferon (IFN) production and dramatically suppressed both lung proliferating CD127+ST2+ ILC2s and Alternaria- and IL-33-induced lung inflammation. Further, transcriptomic analysis of CD127-ST2- Thy1.2+ ILCs, which were expanded and activated by CDG, revealed an ILC1 signature. CDG administration led to accumulation of IFN{gamma}+ and T-bet+ ILC1s, as well as neutrophilia, independent of IL-18R, IL-12, and STAT6 but dependent on stimulator of interferon genes (STING) and partially dependent on type 1 IFN signaling. Thus, CDG potently suppresses ILC2-driven lung inflammation and promotes ILC1 responses. These results suggest potential therapeutic modulation of STING to suppress type 2 inflammation and/or increase anti-viral responses during respiratory infections.

immunology↗

bioRxiv2019

Tpm3.1 association with actin stress fibers is required for lens epithelial to mesenchymal transition

PurposeEpithelial to mesenchymal transition (EMT) is a cause of anterior and posterior subcapsular cataracts. Central to EMT is the formation of actin stress fibers. Targeting specific, stress fiber associated tropomyosin in epithelial cells may be a means to prevent stress fiber formation and repress lens EMT.\n\nMethodsWe identified Tpm isoforms in mouse immortalized lens epithelial cells and isolated whole lenses by semi-quantitative PCR followed Sanger sequencing. We focused on the role of one particular tropomyosin isoform, Tpm3.1, in EMT. To stimulate EMT, we cultured cells or native lenses in TGF{beta}2. To test the function of Tpm3.1, we exposed cells or whole lenses to a Tpm3.1-specific chemical inhibitor, TR100, as well as investigated lenses from Tpm3.1 knockout mice. We examined stress fiber formation by confocal microscopy and assessed EMT progression by sma mRNA (qPCR) and protein (WES immunoassay) analysis.\n\nResultsLens epithelial cells express eight tropomyosin isoforms. Cell culture studies showed that TGF{beta}2 treatment results in an upregulation of Tpm3.1, which associates with actin in stress fibers. TR100 prevents stress fiber formation and reduces sma in TGF{beta}2 treated cells. We confirmed the role of Tpm3.1 in lens epithelial cells in the native lens ex vivo. Culture of whole lenses in the presence of TGF{beta}2 results in stress fiber formation at the basal regions of epithelial cells. Knockout of Tpm3.1 or treatment of lenses with TR100 prevents basal stress fiber formation and reduces epithelial sma levels.\n\nConclusionTargeting specific stress fiber associated tropomyosin isoform, Tpm3.1, is a means to represses lens EMT.

cell biology↗

bioRxiv2018

Tropomyosin 3.5 protects F-actin networks required for tissue biomechanical properties

Tropomyosins (Tpms) stabilize F-actin and regulate interactions with other actin-binding proteins. The eye lens changes shape in order to fine focus light to transmit a clear image, and thus lens organ function is tied to its biomechanical properties, presenting an opportunity to study Tpm functions in tissue mechanics. The major mouse lens Tpm is Tpm3.5 (TM5NM5), a previously unstudied isoform. Decreased levels of Tpm3.5 lead to softer and less mechanically resilient lenses that are unable to resume their original shape after compression. While cell organization and morphology appear unaffected, Tmod1 dissociates from the membrane in Tpm3.5-deficient lens fiber cells resulting in reorganization of the spectrin-F-actin and -actinin-F-actin networks at the membrane. These rearranged F-actin networks appear to be less able to support mechanical load and resilience leading to an overall change in tissue mechanical properties. This is the first in vivo evidence that Tpm is essential for cell biomechanical stability in a load-bearing non-muscle tissue and indicates that Tpm3.5 protects mechanically stable, load-bearing F-actin in vivo.\n\nSummaryTropomyosin 3.5 stabilizes F-actin in eye lens fiber cells and promotes normal tissue biomechanical properties. Tpm3.5 deficiency leads to F-actin network rearrangements and decreased lens stiffness and resilience.

cell biology↗