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Biology subjects

Lindahl, M.

Publications and source records attributed to Lindahl, M..

4 recordsLinked to original sources

MANF Clears Mutant Uromodulin in Human Kidney Organoids of Autosomal Dominant Tubulointerstitial Kidney Disease

Autosomal dominant tubulointerstitial kidney disease due to uromodulin mutations (ADTKD-UMOD) is one of the leading hereditary kidney diseases. Currently there is no targeted treatment. To illuminate human relevance of mesencephalic astrocyte-derived neurotrophic factor (MANF)-based therapy, we have established patient induced pluripotent stem cell (iPSC)-derived kidney organoid model carrying UMOD p.H177-R185del, the leading mutation causing ADTKD. We have discovered that MANF can directly bind and repress ER calcium release channel IP3R1, thus enhancing AMPK-induced autophagy in a TRIB3-dependent manner. The therapeutic implication of this finding may well be extended to other protein misfolding diseases.

genetics↗

Mechanism and cellular actions of the potent AMPK inhibitor BAY-3827

Inhibition of AMP-activated protein kinase (AMPK) is under increasing investigation for its therapeutic potential in many diseases, including certain cancers. However, existing AMPK- inhibitors available as tool compounds are largely limited to compound C/dorsomorphin and SBI-0206965, both of which suffer from poor selectivity and off-target effects. Here we describe the structure-based molecular insights and cellular actions of a recently identified potent AMPK inhibitor, BAY-3827. Kinase selectivity profiling and sequence analyses of kinases that are highly or weakly inhibited by BAY-3827 uncovered key conserved residues involved in its inhibitory mechanism. A 2.5 [A] co-crystal structure of the AMPK kinase domain (KD)-BAY-3827 complex and comparison with known KD-inhibitor structures, revealed an overlapping site in the ATP-binding pocket and an C helix-out conformation. A distinct feature of the BAY-3827-bound state is the formation of a disulfide bridge between the D helix Cys106 and the activation loop residue Cys174. This bridge appears to stabilize the activation loop such that Asn162 repositions the DFG motif Phe158 toward the C-terminal kinase lobe, displacing His137 and disrupting the regulatory spine, thereby promoting an inactive state. In hepatocytes, 2.5-5 M BAY-3827, but not the structurally resembling inactive BAY-974, fully blocked AMPK activator (MK-8722)-mediated phosphorylation of ACC1 and corresponding inhibition of lipogenesis. Unbiased transcriptome analysis in MK- 8722-treated wild-type and AMPK-null hepatocytes revealed that 5 M BAY-3827 downregulated >30% of MK-8722-stimulated AMPK-dependent genes. Based on its greater selectivity and potency substantiated by comprehensive structural and cellular investigations, BAY-3827 is a powerful tool to delineate AMPK functions. One-sentence summaryWe provide the mechanism of action of the potent and selective AMPK inhibitor BAY-3827, which blocks AMPK-dependent cellular functions.

biochemistry↗

MANF stimulates autophagy and restores mitochondrial homeostasis to treat toxic proteinopathy

Misfolded protein aggregates may cause toxic proteinopathy, including autosomal dominant tubulointerstitial kidney disease due to uromodulin mutations (ADTKD-UMOD), one of the leading hereditary kidney diseases, and Alzheimers disease etc. There are no targeted therapies. ADTKD is also a genetic form of renal fibrosis and chronic kidney disease, which affects 500 million people worldwide. For the first time, in our newly generated mouse model recapitulating human ADTKD-UMOD carrying a leading UMOD deletion mutation, we show that autophagy/mitophagy and mitochondrial biogenesis are severely impaired, leading to cGAS- STING activation and tubular injury. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a novel endoplasmic reticulum stress-regulated secreted protein. We provide the first study that inducible tubular overexpression of MANF after the onset of disease stimulates autophagy/mitophagy and clearance of the misfolded UMOD, and promotes mitochondrial biogenesis through p-AMPK enhancement, resulting in protection of kidney function. Conversely, genetic ablation of endogenous MANF upregulated in the mutant mouse and human tubular cells worsens autophagy suppression and kidney fibrosis. Together, we discover MANF as a novel biotherapeutic protein and elucidate previously unknown mechanisms of MANF in regulating organelle homeostasis to treat ADTKD, which may have broad therapeutic application to treat various proteinopathies.

cell biology↗

A Calcium/Palmitoylation Switch Interfaces the Signaling Networks of Stress Response and Transition to Flowering

The precise timing of flowering in adverse environments is critical for plants to secure reproductive success. We report a novel mechanism controlling the time of flowering by which the palmitoylation-dependent nuclear import of protein SOS3/CBL4, a Ca2+-signaling intermediary in the plant response to salinity, results in the selective stabilization of the flowering time regulator GIGANTEA inside the nucleus under salt stress, while degradation of GIGANTEA in the cytosol releases the protein kinase SOS2 to achieve salt tolerance. S-acylation of SOS3 was critical for its nuclear localization and the promotion of flowering, but dispensable for salt tolerance. SOS3 interacted with the photoperiodic flowering components GIGANTEA and FKF1 on the CONSTANS gene promoter to sustain the transcription of CO and FT under salinity. Thus, SOS3 acts as a Ca2+- and palmitoylation-dependent molecular switch that fine-tunes flowering in a saline environment through the shared spatial separation and selective stabilization of GIGANTEA. The SOS3 protein connects two signaling networks to co-regulate stress adaptation and time of flowering. Short summaryS-acylation promoted the nuclear import of SOS3/CBL4 for the selective stabilization of the photoperiodic floral regulator GIGANTEA to fine-tune flowering time in a saline environment. Spatial separation of SOS3 acts as a molecular switch co-regulating stress adaptation and time of flowering.

plant biology↗