4 research outputs found
Recommended from our members
Controlled delivery of bioactive molecules into live cells using the bacterial mechanosensitive channel MscL
Bacterial mechanosensitive channels are some of the largest pores in nature. In particular, MscL, with a pore diameter > 25 Ã…, allows passage of large organic ions and small proteins. Functional MscL reconstitution into lipids has been proposed for applications in vesicular-based drug release. Here we show that these channels can be functionally expressed in mammalian cells to afford rapid controlled uptake of membrane impermeable molecules. We first demonstrate that MscL gating in response to increased membrane tension is preserved in mammalian cell membranes. Molecular delivery is controlled by adopting an established method of MscL charge-induced activation. We then determine pore size limitations using fluorescently labeled model cargoes. Finally, we activate MscL to introduce the cell-impermeable bi-cyclic peptide phalloidin, a specific marker for actin filaments, into cells. We propose that MscL will be a useful tool for gated and controlled delivery of bioactive molecules into cells
Recommended from our members
Primary cilia are specialized calcium signaling organelles
Summary Primary cilia are solitary nonmotile extensions of the centriole found on nearly all nucleated eukaryotic cells between cell divisions. Only ∼200-300 nm in diameter and a few microns long, they are separated from the cytoplasm by the ciliary neck and basal body. Often called sensory cilia, they are hypothesized to receive chemical and mechanical stimuli and initiate specific cellular signal transduction pathways. When activated by a ligand, Hedgehog (Hh) pathway proteins, such as Gli2 and Smoothened (Smo), translocate from the cell into the cilium1,2. Mutations in primary ciliary proteins are associated with severe developmental defects3. The ionic conditions, permeability of the primary cilia membrane, and effectiveness of the diffusion barriers between the cilia and cell body are unknown. Here we show that cilia are a unique calcium compartment regulated by a heteromeric TRP channel, PKD1-L1/PKD2-L1. In contrast to the hypothesis that polycystin (PKD) channels initiate changes in ciliary calcium that are conducted into the cytoplasm4, we show that changes in ciliary calcium concentration ([Ca2+]cilia) occur without substantially altering global cytoplasmic calcium ([Ca2+]cyto). PKD1-L1/PKD2-L1 acts as a ciliary calcium channel controlling [Ca2+]cilia and thereby modifying Smo-activated Gli2 translocation and Gli1 expression
Long-term visual and systemic prognoses of 83 cases of biopsy-proven sarcoid uveitis
International audienceAIMS: To determine the long-term visual and systemic outcomes of uveitis patients with biopsy-proven sarcoidosis. METHODS: A retrospective study of biopsy-proven sarcoid uveitis, with a 3-year minimum follow-up, seen at Lyon University Hospital, between April 2004 and January 2016. RESULTS: A total of 83 patients were included, with a median age at onset of 52 (37-62) years and an unbalanced gender ratio (women 77.1%). Thirty-one patients had original systemic sarcoidosis in addition to ocular localisation, whereas 52 initially presented with isolated sarcoid uveitis. Among the latter, 7.7% (n=4) developed an extraocular disease after a median follow-up duration of 60 (44-110) months. The systemic spread in these patients included cutaneous sarcoids (n=2), arthritis (n=1) and multiple mononeuritis (n=1). Complete visual recovery was obtained for 60.2% of all patients and 89.2% had retrieved best-corrected visual acuity (BCVA) \\textgreater20/50 in both eyes. A unilateral loss of BCVA of worse than 20/200 was documented in two patients in the isolated sarcoid uveitis group. No patient suffered from bilateral severe visual impairment or blindness. Factors linked to a poor visual prognosis, defined by BCV