Publikationen

Potent optogenetic regulation of gene expression in mammalian cells for bioproduction and basic research

2025-12-29T12:46:32Z

Potent optogenetic regulation of gene expression in mammalian cells for bioproduction and basic research Gebel, Jeannette; Ciglieri, Elisa; Stahl, Rainer; Duthie, Fraser; Frechen, Fabian; Möglich, Andreas; Müller-Hartmann, Herbert; Schmidt, Hanns-Martin; Wachten, Dagmar Precise temporal and spatial control of gene expression greatly benefits the study of specific cellular circuits and activities. Compared to chemical inducers, light-dependent control of gene expression by optogenetics achieves a higher spatial and temporal resolution. Beyond basic research, this could also prove decisive for manufacturing difficult-to-express proteins in pharmaceutical bioproduction. However, current optogenetic gene-expression systems limit this application in mammalian cells, as expression levels and the degree of induction upon light stimulation are insufficient. To overcome this limitation, we designed a photoswitch by fusing the blue light-activated light–oxygen–voltage receptor EL222 from Erythrobacter litoralis to the three transcriptional activator domains VP64, p65, and Rta in tandem. The result ant photoswitch, dubbed DEL-VPR, allows up to a 570-fold induction of target gene expression by blue light, thereby achieving expression levels of strong constitutive promoters. Here, we used DEL-VPR to enable light-induced expression of complex monoclonal and bispecific antibodies with reduced byproduct expression and increased yield of functional protein complexes. Our approach offers temporally controlled yet strong gene expression and applies to academic and industrial settings.

Renal tissue-resident macrophages promote cystogenesis in early polycystic kidney disease

2025-12-29T11:16:35Z

Renal tissue-resident macrophages promote cystogenesis in early polycystic kidney disease Karl, Rudolfo; Ashraf, Arsila Palliyulla Kariat; Viola, Maria Francesca; Hopp, Katharina; Mass, Elvira; Wachten, Dagmar Autosomal-dominant polycystic kidney disease (ADPKD) is a ciliopathy characterized bymutations in PKD1 or PKD2, which drive cystogenesis in renal epithelial cells. Immune cells, particularly macrophages, contribute to disease progression, yet their role remains incompletely understood. Here, we performed an in-depth analysis of renal macrophage ontogeny and phenotype and investigated their function in an ADPKD mouse model (Pkd1^RC/RC) with adult onset and slow disease progression. We demonstrate that the numbers of tissue-resident macrophages were already increased before cyst formation. Using a flow cytometry screening panel, we further characterized the tissue-resident macrophage populations using surface markers and identified a novel marker that shows the potential to determine macrophage remodeling at different disease stages. To reveal the cellular interaction of tissue-resident macrophages and renal epithelial cells in further detail, we established a 3D co-culture system, demonstrating that tissue-resident macrophages from Pkd1^RC/RC mice, isolated at a stage before cysts were observed, already showed enhanced cystogenesis in vitro. These findings underscore the crucial role of tissue-resident macrophages in ADPKD and suggest targeting epithelial cell–macrophage interactions as a promising therapeutic avenue.

Primary cilia signalling at a glance

2025-11-13T09:46:42Z

Primary cilia signalling at a glance Wachten, Dagmar; Christensen, Søren Tvorup The primary cilium is a solitary, microtubule-based organelle present on most vertebrate cells, where it functions as a central hub for sensing and transducing extracellular signals. This Cell Science at a Glance article highlights how primary cilia integrate key signalling pathways – including Hedgehog, G protein-coupled receptor, TRP ion channel, receptor tyrosine kinase and transforming growth factor β superfamily signalling – to regulate cellular processes, tissue architecture and organ function. We also describe how defects in ciliary structure or signalling give rise to ciliopathies, a diverse group of disorders affecting multiple organs and systems. Finally,we explore emerging insights into how dynamic changes in ciliary composition generate cell type- and context-specific signalling signatures, positioning the cilium as a convergence point for multiple signalling branches that coordinate development and homeostasis in time and space. The accompanying poster provides further detail on signallingmodules and specializations across cell types.

Cold-induced expression of a truncated adenylyl cyclase 3 acts as rheostat to brown fat function

2025-08-12T07:46:27Z

Cold-induced expression of a truncated adenylyl cyclase 3 acts as rheostat to brown fat function Khani, Sajjad; Topel, Hande; Kardinal, Ronja; Tavanez, Ana Rita; Josephrajan, Ajeetha; Larsen, Bjørk Ditlev Marcher; Gaudry, Michael James; Leyendecker, Philipp; Meincke Egedal, Nadia; Güller, Aylin Seren; Stanic, Natasa; Ruppert, Phillip M. M.; Gaziano, Isabella; Hansmeier, Nils Rouven; Schmidt, Elena; Klemm, Paul; Vagliano, Lara-Marie; Stahl, Rainer; Duthie, Fraser; Krause, Jens-Henning; Bici, Ana; Engelhard, Christoph Andreas; Gohlke, Sabrina; Frommolt, Peter; Gnad, Thorsten; Rada-Iglesias, Alvaro; Pradas-Juni, Marta; Schulz, Tim Julius; Wunderlich, Frank Thomas; Pfeifer, Alexander; Bartelt, Alexander; Jastroch, Martin; Wachten, Dagmar; Kornfeld, Jan-Wilhelm Promoting brown adipose tissue (BAT) activity innovatively targetsobesity and metabolic disease. While thermogenic activation of BAT is wellunderstood, the rheostatic regulation of BAT to avoid excessive energy dissipation remains ill-defined. Here, we demonstrate that adenylyl cyclase3 (AC3) is key for BAT function. We identified a cold-inducible promoter thatgenerates a 5′ truncated AC3 mRNA isoform (Adcy3-at), whose expression is driven by a cold-induced, truncated isoform of PPARGC1A (PPARGC1A-AT).Male mice lacking Adcy3-at display increased energy expenditure and are resistant to obesity and ensuing metabolic imbalances. Mouse and human AC3-AT are retained in the endoplasmic reticulum, unable to translocate to the plasma membrane and lack enzymatic activity. AC3-AT interacts with AC3 and sequesters it in the endoplasmic reticulum, reducing the pool of adenylyl cyclases available for G-protein-mediated cAMP synthesis. Thus, AC3-AT acts as a cold-induced rheostat in BAT, limiting adverse consequences of cAMP activity during chronic BAT activation.