Heinz D. Osiewacz

Goethe-Universität Frankfurt am Main · Institute of Molecular Biosciences

The serine peptidase CLPP is conserved among bacteria, chloroplasts, and mitochondria. In humans and mice, its loss causes Perrault syndrome, which presents with growth deficits, infertility, deafness, and ataxia. In the filamentous fungus Podospora anserina, CLPP loss leads to longevity. CLPP substrates are selected by CLPX, an AAA+ unfoldase. CLP...

Serine peptidase CLPP is conserved among bacteria, chloroplasts, and mitochondria. In humans and mice, its loss causes Perrault syndrome with growth deficit, infertility, deafness, and ataxia. In the filamentous fungus Podospora anserina, CLPP-loss leads to longevity. CLPP substrates are selected by CLPX, an AAA+ unfoldase. CLPX is known to target...

The formation of fruiting bodies is a highly regulated process that requires the coordinated formation of different cell types. By analyzing developmental mutants, many developmental factors have already been identified. Yet, a complete understanding of fruiting body formation is still lacking. In this study, we analyzed developmental mutant pro34...

Cardiolipin, the mitochondria marker lipid, is crucially involved in stabilizing the inner mitochondrial membrane and is vital for the activity of mitochondrial proteins and protein complexes. Directly targeting cardiolipin by a chemical-biology approach and thereby altering the cellular concentration of "available" cardiolipin eventually allows to...

Mitochondria are dynamic eukaryotic organelles involved in a variety of essential cellular processes including the generation of adenosine triphosphate (ATP) and reactive oxygen species as well as in the control of apoptosis and autophagy. Impairments of mitochondrial functions lead to aging and disease. Previous work with the ascomycete Podospora...

The filamentous ascomycete Podospora anserina is a well-established model system to study organismic aging. Its senescence syndrome has been investigated for more than fifty years and turned out to have a strong mitochondrial etiology. Several different mitochondrial pathways were demonstrated to affect aging and lifespan. Here, we present an updat...

Function of mitochondria largely depends on a characteristic ultrastructure with typical invaginations, namely the cristae of the inner mitochondrial membrane. The mitochondrial signature phospholipid cardiolipin (CL), the F1Fo-ATP-synthase, and the ‘mitochondrial contact site and cristae organizing system’ (MICOS) complex are involved in this proc...

Mitochondria are dynamic eukaryotic organelles involved in a variety of essential cellular processes including the generation of adenosine triphosphate (ATP) and reactive oxygen species (ROS) as well as in the control of apoptosis and autophagy. Impairments of mitochondrial functions lead to aging and disease. Previous works with the ascomycete Pod...

The maintenance of cellular homeostasis over time is essential to avoid the degeneration of biological systems leading to aging and disease. Several interconnected pathways are active in this kind of quality control. One of them is autophagy, the vacuolar degradation of cellular components. The absence of the sorting nexin PaATG24 (SNX4 in other or...

The accumulation of functionally impaired mitochondria is a key event in aging. Previous works with the fungal aging model Podospora anserina demonstrated pronounced age-dependent changes of mitochondrial morphology and ultrastructure, as well as alterations of transcript and protein levels, including individual proteins of the oxidative phosphoryl...

Mitochondria are ubiquitous organelles of eukaryotic organisms with a number of essential functions, including synthesis of iron-sulfur clusters, amino acids, lipids, and adenosine triphosphate (ATP). During aging of the fungal aging model Podospora anserina, the inner mitochondrial membrane (IMM) undergoes prominent morphological alterations, ulti...

Research on Podospora anserina unraveled a network of molecular pathways affecting biological aging. In particular, a number of pathways active in the control of mitochondria were identified on different levels. A long-known key process active during aging of P. anserina is the age-related reorganization of the mitochondrial DNA (mtDNA). Mechanisms...

Mitochondrial F1Fo-ATP-synthase dimers play a critical role in shaping and maintenance of mitochondrial ultrastructure. Previous studies have revealed that ablation of the F1Fo-ATP-synthase assembly factor PaATPE of the ascomycete Podospora anserina strongly affects cristae formation, increases hydrogen peroxide levels, impairs mitochondrial functi...

Organismic aging is known to be controlled by genetic and environmental traits. Pathways involved in the control of cellular metabolism play a crucial role. Previously, we identified a role of PaCLPP, a mitochondrial matrix protease, in the control of the mitochondrial energy metabolism, aging, and lifespan of the fungal aging model Podospora anser...

Metacaspases and paracaspases are proteases that were first identified as containing a caspase-like structural fold (Uren et al., 2000). Like caspases, metacas-pases and paracaspases are multi-functional proteins regulating diverse biological phenomena, such as aging, immunity , proteostasis, and programmed cell death. The broad phylogenetic distri...

Sorting nexins are a conserved protein family involved in vesicle transport, membrane trafficking and protein sorting. The sorting nexin ATG24/SNX4 has been demonstrated to be involved in different autophagy pathways and in endosomal trafficking. However, its impact on cellular quality control and on aging and development is still elusive. Here we...

The integration of the available experimental data represents a main problem in systems biology. In particular, in medical sciences, many new data became available, but often data are incomplete and of different quality and quantity. Here, we describe a method for the automatic derivation of protein–protein interaction networks based on homology se...

Autophagy maintains hematopoietic stem cell integrity and prevents malignant transformation. In addition to bulk degradation, selective autophagy serves as an intracellular quality control mechanism and requires autophagy receptors, such as p62 (SQSTM1), to specifically bridge the ubiquitinated cargos into autophagosomes. Here, we investigated the...

In most cases, macroautophagy/autophagy serves to alleviate cellular stress and acts in a pro-survival manner. However, the effects of autophagy are highly contextual, and autophagic cell death (ACD) is emerging as an alternative paradigm of (stress- and drug-induced) cell demise. AT 101 ([-]-gossypol), a natural compound from cotton seeds, induces...

Quercetin is a flavonoid that is ubiquitously found in vegetables and fruits. Like other flavonoids, it is active in balancing cellular reactive oxygen species (ROS) levels and has a cyto-protective function. Previously, a link between ROS balancing, aging, and the activity of O-methyltransferases was reported in different organisms including the a...

In aerobic organisms, mitochondrial F1Fo-ATP-synthase is the major site of ATP production. Beside this fundamental role, the protein complex is involved in shaping and maintenance of cristae. Previous electron microscopic studies identified the dissociation of F1Fo-ATP-synthase dimers and oligomers during organismic aging correlating with a massive...

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing....

Elucidating the biology of yeast in its full complexity has major implications for science, medicine and industry. One of the most critical processes determining yeast life and physiology is cellular demise. However, the investigation of yeast cell death is a relatively young field, and a widely accepted set of concepts and terms is still missing....

Fig. S1 Southern blot analyses of genomic DNA for verification of different P. anserina mutant strains. Fig. S2 Determination of the mitochondrial AOX protein amount in ∆PaClpXP and the wild type. Fig. S3 Western blot analysis using the PaSod3 H26L ::Gfp mitophagy reporter strain. Fig. S4 Methyl methanesulfonate (MMS) as a tool to study mitophag...

Prion protein (PrP) is essentially known for its capacity to induce neurodegenerative prion diseases in mammals caused by a conformational change in its normal cellular isoform (PrPC) into an infectious and disease-associated misfolded form, called scrapie isoform (PrPSc). Although its sequence is highly conserved, less information is available on...

Gossypol, a natural polyphenolic compound from cotton seeds, is known to trigger different forms of cell death in various types of cancer. Gossypol acts as a Bcl-2 inhibitor that induces apoptosis in apoptosis-competent cells. In apoptosis-resistant cancers such as glioblastoma, it triggers a non-apoptotic type of cell death associated with increas...

The degradation of nonfunctional mitochondrial proteins is of fundamental relevance for maintenance of cellular homeostasis. The heteromeric CLPXP protein complex in the mitochondrial matrix is part of this process. In the fungal aging model Podospora anserina, ablation of CLPXP leads to an increase in healthy lifespan. Here, we report that this co...

Mitochondrial dysfunction is causatively linked to organismal aging and the development of degenerative diseases. Here we describe stress-dependent opposing roles of mitophagy, the selective autophagic degradation of mitochondria, in aging and lifespan control. We report that the ablation of the mitochondrial superoxide dismutase which is involved...

Background Autophagy is a conserved molecular pathway involved in the degradation and recycling of cellular components. It is active either as response to starvation or molecular damage. Evidence is emerging that autophagy plays a key role in the degradation of damaged cellular components and thereby affects aging and lifespan control. In earlier s...

We describe a method for the three-dimensional live imaging of filamentous fungi with light sheet-based fluorescence microscopy (LSFM). LSFM provides completely new opportunities to investigate the biology of fungal cells and other microorganisms with high spatial and temporal resolution. As an example, we study the established aging model Podospor...

The filamentous ascomycete Podospora anserina is a well established aging model in which a central role of mitochondria in the control of organismal aging has been demonstrated. A number of different mitochondrial quality control pathways, including those involved in the control of respiration, DNA maintenance, proteolysis and dynamics affect aging...

Biological aging is the progressive physiological impairment leading to death of living beings. In humans, ageing is associated with the development of a number of degenerative diseases. Although intensively studied, there are currently no mechanisms elucidated explaining all aspects of aging. Further research into this direction is needed. Some fu...

The mitochondrial permeability transition pore plays a key role in programmed cell death and the induction of autophagy. Opening of the pore is regulated by the mitochondrial peptidyl prolyl-cis, trans-isomerase cyclophilin D (CYPD). Previously it was shown in the aging model organism Podospora anserina that PaCYPD abundance increases during aging...

The free radical theory of ageing is based on the idea that reactive oxygen species (ROS) may lead to the accumulation of age-related protein oxidation. Since the majority of cellular ROS is generated at the respiratory electron transport chain, this study focuses on the mitochondrial proteome of the ageing model Podospora anserina as target for RO...

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring au...

Research on fungal senescence, in particular on Podospora anserina and Saccharomyces cerevisiae, has unraveled a network of molecular pathways affecting aging and lifespan. The physiological decline of biological systems is linked to impairments of cellular machines and to the generation of ROS which arise during normal metabolism (e.g., at the res...

We introduce Path2PPI, a new R package to identify protein–protein interaction (PPI) networks for fully sequenced organisms for which nearly none PPI are known. Path2PPI predicts PPI networks based on sets of proteins from well-established model organisms, providing an intuitive visualization and usability. It can be used to combine and transfer in...

Maintenance of mitochondria is achieved by several mechanisms, including the regulation of mitochondrial proteostasis. The matrix protease CLPXP, involved in protein quality control, has been implicated in ageing and disease. However, particularly due to the lack of knowledge of CLPXP’s substrate spectrum, only little is known about the pathways an...

Mitochondrial respiratory supercomplexes (mtRSCs) are stoichiometric assemblies of electron transport chain (ETC) complexes in the inner mitochondrial membrane. They are hypothesized to regulate electron flow, the generation of reactive oxygen species (ROS) and to stabilize ETC complexes. Using the fungal ageing model Podospora anserina, we investi...

Low levels of reactive oxygen species (ROS) act as important signaling molecules but in excess they can damage biomolecules. ROS regulation is therefore of key importance. Several polyphenols in general and flavonoids in particular have the potential to generate hydroxyl radicals, the most hazardous among all ROS. However, the generation of a hydro...

For biological systems, balancing cellular levels of reactive oxygen species (ROS) is of great importance because ROS are both, essential for cellular signaling and dangerous in causing molecular damage. Cellular ROS abundance is controlled by a delicate network of molecular pathways. Within this network, superoxide dismutases (SOD's) are active in...

Aging of biological systems is accompanied by degeneration of mitochondrial functions. Different pathways are active to counteract the processes which lead to mitochondrial dysfunction. Mitochondrial dynamics, the fission and fusion of mitochondria, is one of these quality control pathways. Mitophagy, the controlled degradation of mitochondria, is...

Time-dependent impairments of mitochondrial function play a key role in biological aging. Work on fungal aging models has been instrumental in unraveling basic mechanisms leading to mitochondrial dysfunction and the identification of different pathways active in keeping mitochondria ‘healthy’ over time. Pathways including those involved in reactive...

The degradation of damaged proteins is an important vital function especially during aging and stress. The ubiquitin proteasome system is one of the major cellular machineries for protein degradation. Health and longevity are associated with high proteasome activity. To demonstrate such a role in aging of Podospora anserina, we first analyzed the t...

In biological systems, reactive oxygen species (ROS) represent ‘double edged swords’: as signaling molecules they are essential for proper development, as reactive agents they cause molecular damage and adverse effects like degeneration and aging. A well-coordinated control of ROS is therefore of key importance. Superoxide dismutases (SODs) are enz...

The mitochondrial free radical theory of aging (MFRTA) states that reactive oxygen species (ROS) generated at the respiratory electron transport chain are active in causing age-related damage of biomolecules like lipids, nucleic acids and proteins. Accumulation of this kind of damage results in functional impairments, aging and death of biological...

Various molecular and cellular pathways are active in eukaryotes to control the quality and integrity of mitochondria. These pathways are involved in keeping a 'healthy' population of this essential organelle during the lifetime of the organism. Quality control (QC) systems counteract processes that lead to organellar dysfunction manifesting as deg...

Aging of biological systems is influenced by various factors, conditions and processes. Among others, processes allowing organisms to deal with various types of stress are of key importance. In particular, oxidative stress as the result of the generation of reactive oxygen species (ROS) at the mitochondrial respiratory chain and the accumulation of...

The filamentous ascomycete Podospora anserina is a well-established aging model in which a variety of different pathways, including those involved in the control of respiration, ROS generation and scavenging, DNA maintenance, proteostasis, mitochondrial dynamics, and programmed cell death have previously been demonstrated to affect aging and life s...

Aging of biological systems controlled by various processes which have a potential impact on gene expression. Here we report a genome-wide an scriptome analysis of the fungal aging model Podospora anserina. Total RNA of three individuals defined age were pooled and analyzed by SuperSAGE (serial analysis of gene expression). A bioinformatics analyst...

Aging is one of the most fundamental, yet least understood biological processes that affect all forms of eukaryotic life. Mitochondria are intimately involved in aging, but the underlying molecular mechanisms are largely unknown. Electron cryotomography of whole mitochondria from the aging model organism Podospora anserina revealed profound age-dep...

Aging is one of the most fundamental, yet least understood biological processes that affect all forms of eukaryotic life. Mitochondria are intimately involved in aging, but the underlying molecular mechanisms are largely unknown. Electron cryotomography of whole mitochondria from the aging model organism Podospora anserina revealed profound age-dep...

Many questions concerning the molecular processes during biological aging remain unanswered. Since mitochondria are central players in aging, we applied quantitative two-dimensional difference gel electrophoresis (2D-DIGE) coupled to protein identification by mass spectrometry to study the age-dependent changes in the mitochondrial proteome of the...

The peptidase CLPP is conserved from bacteria to humans. In the mitochondrial matrix, it multimerizes and forms a macromolecular proteasome-like cylinder together with the chaperone CLPX. In spite of a known relevance for the mitochondrial unfolded protein response, its substrates and tissue-specific roles are unclear in mammals. Recessive CLPP mut...

A fundamental impact of mitochondria on biological aging has been suggested decades ago. One prominent theory explains aging as the result of the age-related accumulation of random molecular damage of biomolecules resulting from the reaction of reactive oxygen species, the majority of which are generated in mitochondria. Although this concept appea...

The two metacaspases MCA1 and MCA2 of the fungal aging model organism Podospora anserina (PaMCA1 and PaMCA2, respectively) have previously been demonstrated to be involved in the control of programmed cell death (PCD) and life span. In order to identify specific pathways and components which are controlled by the activity of these enzymes, we set o...

In the present work, we indicate that copper is involved in the senescence of human diploid fibroblasts and we describe mechanisms to explain it. Using different techniques, we show for the first time an accumulation of copper in cells during replicative senescence. This accumulation seems to be co-localized with lipofuscin. Second, we observed tha...

Maintenance of functional mitochondria is essential in order to prevent degenerative processes leading to disease and aging. Mitochondrial dynamics plays a crucial role in ensuring mitochondrial quality but may also generate and spread molecular damage through a population of mitochondria. Computational simulations suggest that this dynamics is adv...

Mitochondrial maintenance crucially depends on the quality control of proteins by various chaperones, proteases and repair enzymes. While most of the involved components have been studied in some detail, little is known on the biological role of the CLPXP protease complex located in the mitochondrial matrix. Here we show that deletion of PaClpP, en...

Supplementary Figures S1-S5

Podospora anserina is an extensively studied model organism to unravel the mechanism of organismal aging. This filamentous fungus is short-lived and accessible to experimentation. Aging and lifespan are controlled by genetic and environmental traits and, in this model, have a strong mitochondrial etiology. Here, we describe methods and protocols to...

Biological aging is a complex and multifactorial process driven by genetic, environmental, and stochastic factors that lead to the physiological decline of biological systems. In humans, old age is the most important risk factor for the development of degenerative diseases, some of which are severe (e.g., dementia, cancer). Understanding the basic...

The regulation of cellular copper homeostasis is crucial in biology. Impairments lead to severe dysfunctions and are known to affect aging and development. Previously, a loss-of-function mutation in the gene encoding the copper-sensing and copper-regulated transcription factor GRISEA of the filamentous fungus Podospora anserina was reported to lead...

GO term enrichment analysis. (DOCX)

Selected genes of P. anserina and their expression level comparing grisea mutant strain to the wild type. (DOCX)

Transcripts of melanin synthesis proteins. (DOCX)

Transcripts of proteins involved in mitochondrial protein quality control. (DOCX)

Summary of primer sequences used in qRT-PCR analysis of selected genes. (DOCX)

Transcripts of siderophore iron transport proteins. (DOCX)

Transcripts of proteins of the respiratory chain. (DOCX)

Transcripts of proteins involved in ROS detoxification. (DOCX)

Transcripts of proteins of the secondary metabolism. (DOCX)

Transcripts encoding proteins of RIA iron transport. (DOCX)