Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging

Thaung, Jörgen; Knutsson, Per; Popovic, Zoran; Owner-Petersen, Mette

doi:10.1364/oe.17.004454

Cited by 51 publications

(33 citation statements)

References 22 publications

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“…BY1 cells transfected with PAK1-KD showed a phenotype similar to that seen in PAK1-and 2-depleted cells, namely formation of numerous small-sized podosomes. These results indicate that PAK1-KD competes with endogenous PAKs to interact with a downstream kinase target CaD, and forms nonproductive complexes with CaD, thereby approaching the dominant-negative effect as reported previously (38). Additionally, disassembly of podosomes by exogenous CaD expression was markedly reverted by the co-expression of PAK1-KD (Fig.…”

Section: Inhibitory Function Of Pak In Podosome Formationsupporting

confidence: 87%

Changes in the Balance between Caldesmon Regulated by p21-activated Kinases and the Arp2/3 Complex Govern Podosome Formation

Morita

Mayanagi

Yoshio

et al. 2007

Journal of Biological Chemistry

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Podosomes are dynamic cell adhesion structures that degrade the extracellular matrix, permitting extracellular matrix remodeling. Accumulating evidence suggests that actin and its associated proteins play a crucial role in podosome dynamics. Caldesmon is localized to the podosomes, and its expression is down-regulated in transformed and cancer cells. Here we studied the regulatory mode of caldesmon in podosome formation in Rous sarcoma virus-transformed fibroblasts. Exogenous expression analyses revealed that caldesmon represses podosome formation triggered by the N-WASP-Arp2/3 pathway. Conversely, depletion of caldesmon by RNA interference induces numerous small-sized podosomes with high dynamics. Caldesmon competes with the Arp2/3 complex for actin binding and thereby inhibits podosome formation. p21-activated kinases (PAK)1 and 2 are also repressors of podosome formation via phosphorylation of caldesmon. Consequently, phosphorylation of caldesmon by PAK1/2 enhances this regulatory mode of caldesmon. Taken together, we conclude that in Rous sarcoma virus-transformed cells, changes in the balance between PAK1/ 2-regulated caldesmon and the Arp2/3 complex govern the formation of podosomes.The podosomes found in monocyte-derived cells, osteoclasts, and smooth muscle cells are protrusions from the ventral surface of the plasma membrane and are highly dynamic structures of cell adhesion (1-5). The similar adherent protrusions formed in Rous sarcoma virus (RSV) 2 -transformed fibroblasts were named invadopodia by Chen (6). Invadopodia degrade the extracellular matrix (ECM) with matrix metalloproteinases, which implicates remodeling of ECM (6). As podosomes and invadopodia appear to be similar in morphology, functions, and molecular compositions, they are considered to be related structures with different cellular contexts. The podosomes are composed of actin, its associated proteins, and signaling molecules (2-4). Within the podosome, a central core of actin filaments is surrounded by a juxtamembranous ring that is enriched in vinculin (7), ␣-actinin (7, 8), talin (7), and nonerythroid spectrin (8, 9). Neural WASP (N-WASP) and the Arp2/3 complex are also localized to the podosomes (10 -12). These proteins function with a variety of other actin-associated proteins, such as cortactin, Cdc42, profilin, and cofilin, to mediate actin polymerization and actin network formation toward the plasma membrane (4). In fact, blocking the functions of N-WASP and the Arp2/3 complex using dominant-negative mutants and RNA interference inhibits podosome formation (11-13), suggesting that N-WASP and the Arp2/3 complex are crucial for the formation and function of these adhesive structures.Caldesmon (CaD), which is an actin-and calmodulin-binding protein, controls smooth muscle and non-muscle actin-myosin interactions (14, 15). Two different molecular weight (M r ) isoforms of CaD are identified: high molecular weight CaD (h-CaD; 120 -150 kDa) and low molecular weight CaD (l-CaD; 70 -80 kDa). They are generated from a single gene by al...

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Section: Inhibitory Function Of Pak In Podosome Formationsupporting

confidence: 87%

Changes in the Balance between Caldesmon Regulated by p21-activated Kinases and the Arp2/3 Complex Govern Podosome Formation

Morita

Mayanagi

Yoshio

et al. 2007

Journal of Biological Chemistry

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“…For a smaller pupil size, aberrations will be less pronounced and the iso-planatic field will be larger. The usable FOV may be increased using multi conjugate AO [79]. Another limiting factor for the FOV in AO-OCT is the available A-scan rate.…”

Section: Field Of View and Motion Correctionmentioning

confidence: 99%

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Pircher

Zawadzki

2017

Biomed. Opt. Express

170

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Abstract:In vivo imaging of the human retina with a resolution that allows visualization of cellular structures has proven to be essential to broaden our knowledge about the physiology of this precious and very complex neural tissue that enables the first steps in vision. Many pathologic changes originate from functional and structural alterations on a cellular scale, long before any degradation in vision can be noted. Therefore, it is important to investigate these tissues with a sufficient level of detail in order to better understand associated disease development or the effects of therapeutic intervention. Optical retinal imaging modalities rely on the optical elements of the eye itself (mainly the cornea and lens) to produce retinal images and are therefore affected by the specific arrangement of these elements and possible imperfections in curvature. Thus, aberrations are introduced to the imaging light and image quality is degraded. To compensate for these aberrations, adaptive optics (AO), a technology initially developed in astronomy, has been utilized. However, the axial sectioning provided by retinal AO-based fundus cameras and scanning laser ophthalmoscope instruments is limited to tens of micrometers because of the rather small available numerical aperture of the eye. To overcome this limitation and thus achieve much higher axial sectioning in the order of 2-5µm, AO has been combined with optical coherence tomography (OCT) into AO-OCT. This enabled for the first time in vivo volumetric retinal imaging with high isotropic resolution. This article summarizes the technical aspects of AO-OCT and provides an overview on its various implementations and some of its clinical applications. In addition, latest developments in the field, such as computational AO-OCT and wavefront sensor less AO-OCT, are covered. 1178-1181 (1991). 2. M. Wojtkowski, B. Kaluzny, and R. J. Zawadzki, "New directions in ophthalmic optical coherence tomography," Optom. Vis. Sci. 89(5), 524-542 (2012). 3. T. E. de Carlo, A. Romano, N. K. Waheed, and J. S. Duker, "A review of optical coherence tomography angiography (OCTA)," Int J Retina Vitreous 1(5), 5 (2015). 4. W. Drexler and J. G. Fujimoto, "State-of-the-art retinal optical coherence tomography," Prog. Retin. Eye Res.27(1), 45-88 (2008). 5. G. Walsh, W. N. Charman, and H. C. Howland, "Objective technique for the determination of monochromatic aberrations of the human eye," J. Opt. Soc. Am. A 1(9), 987-992 (1984). 6. J. Liang and D. R. Williams, "Aberrations and retinal image quality of the normal human eye," J. Opt. Soc. Am.A 14(11), 2873-2883 (1997). Office, 2014). 27. J. Liang, B. Grimm, S. Goelz, and J. F. Bille, "Objective measurement of wave aberrations of the human eye with the use of a Hartmann-Shack wave-front sensor," J. Opt. Soc. Am. A 11(7), 1949-1957 (1994). 28. M. Laslandes, M. Salas, C. K. Hitzenberger, and M. Pircher, "Influence of wave-front sampling in adaptive optics retinal imaging," Biomed. Opt. Express 8(2), 1083-1100 (2017). 29. S. Tuohy and A. G. Podoleanu,...

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“…If the dynamic aspect of the measurement is crucial, multiconjugate adaptive optics may significantly improve the size of the isoaplanetic patches. 24 In the case of static measurements, sequential corrections performed using guide stars uniformly distributed within the sample can be used to synthesize a fully corrected image.…”

Section: Discussion and Prospectsmentioning

confidence: 99%

Adaptive optics for fluorescence wide-field microscopy using spectrally independent guide star and markers

Vermeulen¹,

Muro²,

Pons³

et al. 2011

J. Biomed. Opt.

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Abstract.We describe the implementation and use of an adaptive optics loop in the imaging path of a commercial wide field microscope. We show that it is possible to maintain the optical performances of the original microscope when imaging through aberrant biological samples. The sources used for illuminating the adaptive optics loop are spectrally independent, in excitation and emission, from the sample, so they do not appear in the final image, and their use does not contribute to the sample bleaching. Results are compared with equivalent images obtained with an identical microscope devoid of adaptive optics system. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Dual-conjugate adaptive optics for wide-field high-resolution retinal imaging

Cited by 51 publications

References 22 publications

Changes in the Balance between Caldesmon Regulated by p21-activated Kinases and the Arp2/3 Complex Govern Podosome Formation

Changes in the Balance between Caldesmon Regulated by p21-activated Kinases and the Arp2/3 Complex Govern Podosome Formation

Review of adaptive optics OCT (AO-OCT): principles and applications for retinal imaging [Invited]

Adaptive optics for fluorescence wide-field microscopy using spectrally independent guide star and markers

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