Clinical Chemistry and Other Laboratory Tests on Mouse Plasma or Serum

Examining the liver-pancreas crosstalk reveals a role for the molybdenum cofactor in β-cell regeneration

Regeneration of insulin-producing β-cells is an alternative avenue to manage diabetes, and it is crucial to unravel this process in vivo during physiological responses to the lack of β-cells. Here, we aimed to characterize how hepatocytes can contribute to β-cell regeneration, either directly or indirectly via secreted proteins or metabolites, in a zebrafish model of β-cell loss. Using lineage tracing, we show that hepatocytes do not directly convert into β-cells even under extreme β-cell ablation conditions. A transcriptomic analysis of isolated hepatocytes after β-cell ablation displayed altered lipid- and glucose-related processes. Based on the transcriptomics, we performed a genetic screen that uncovers a potential role of the molybdenum cofactor (Moco) biosynthetic pathway in β-cell regeneration and glucose metabolism in zebrafish. Consistently, molybdenum cofactor synthesis 2 (Mocs2) haploinsufficiency in mice indicated dysregulated glucose metabolism and liver function. Together, our study sheds light on the liver-pancreas crosstalk and suggests that the molybdenum cofactor biosynthesis pathway should be further studied in relation to glucose metabolism and diabetes.

Digital colloid-enhanced Raman spectroscopy for the pharmacokinetic detection of bioorthogonal drugs

Bioorthogonal drug molecules are currently gaining prominence for their excellent efficacy, safety and metabolic stability. Pharmacokinetic study is critical for understanding their mechanisms and guiding pharmacotherapy, which is primarily performed with liquid chromatography-mass spectrometry as the gold standard. For broader and more efficient applications in clinics and fundamental research, further advancements are especially desired in cheap and portable instrumentation as well as rapid and tractable pretreatment procedures. Surface-enhanced Raman spectroscopy (SERS) is capable of label-free detection of various molecules based on the spectral signatures with high sensitivity even down to a single-molecule level. But limited by irreproducibility at low concentrations and spectral interference in complex biofluids, SERS hasn't been widely applied for pharmacokinetics, especially in live animals. In this work, we propose a new method to quantify bioorthogonal drug molecules with signatures at the spectral silent region (SR) by the digital colloid-enhanced Raman spectroscopy (dCERS) technique. This method was first validated using 4-mercaptobenzonitrile in a mixture of analogous molecules, exhibiting reliable and specific identification capability based on the unique SR signature and Poisson-determined quantification accuracy. We further developed a single-step serum pretreatment method and successfully profiled the pharmacokinetic behavior of an anticancer drug, erlotinib, from animal studies. In a word, this method, superior in sensitivity, controllable accuracy, minimal background interference and facile pretreatment and measurement, promises diverse applications in fundamental studies and clinical tests of bioorthogonal drug molecules.

Decreased β-cell volume and insulin secretion but preserved glucose tolerance in a growth hormone insensitive pig model

PURPOSE

Growth hormone (GH) is a central regulator of β-cell proliferation, insulin secretion and sensitivity. Aim of this study was to investigate the effect of GH insensitivity on pancreatic β-cell histomorphology and consequences for metabolism in vivo.

METHODS

Pancreata from pigs with growth hormone receptor deficiency (GHR-KO, n = 12) were analyzed by unbiased quantitative stereology in comparison to wild-type controls (WT, n = 12) at 3 and 7-8.5 months of age. In vivo secretion capacity for insulin and glucose tolerance were assessed by intravenous glucose tolerance tests (ivGTTs) in GHR-KO (n = 3) and WT (n = 3) pigs of the respective age groups.

RESULTS

Unbiased quantitative stereological analyses revealed a significant reduction in total β-cell volume (83% and 73% reduction in young and adult GHR-KO vs. age-matched WT pigs; p < 0.0001) and volume density of β-cells in the pancreas of GHR-KO pigs (42% and 39% reduction in young and adult GHR-KO pigs; p = 0.0018). GHR-KO pigs displayed a significant, age-dependent increase in the proportion of isolated β-cells in the pancreas (28% in young and 97% in adult GHR-KO vs. age-matched WT pigs; p = 0.0009). Despite reduced insulin secretion in ivGTTs, GHR-KO pigs maintained normal glucose tolerance.

CONCLUSION

GH insensitivity in GHR-KO pigs leads to decreased β-cell volume and volume proportion of β-cells in the pancreas, causing a reduced insulin secretion capacity. The increased proportion of isolated β-cells in the pancreas of GHR-KO pigs highlights the dependency on GH stimulation for proper β-cell maturation. Preserved glucose tolerance accomplished with decreased insulin secretion indicates enhanced sensitivity for insulin in GH insensitivity.

Comparative Phenotyping of Mice Reveals Canonical and Noncanonical Physiological Functions of TRα and TRβ

Thyroid hormone (TH) effects are mediated through TH receptors (TRs), TRα1, TRβ1, and TRβ2. The TRs bind to the DNA and regulate expression of TH target genes (canonical signaling). In addition, they mediate activation of signaling pathways (noncanonical signaling). Whether noncanonical TR action contributes to the spectrum of TH effects is largely unknown. The aim of this study was to attribute physiological effects to the TR isoforms and their canonical and noncanonical signaling. We conducted multiparameter phenotyping in male and female TR knockout mice (TRαKO, TRβKO), mice with disrupted canonical signaling due to mutations in the TR DNA binding domain (TRαGS, TRβGS), and their wild-type littermates. Perturbations in senses, especially hearing (mainly TRβ with a lesser impact of TRα), visual acuity, retinal thickness (TRα and TRβ), and in muscle metabolism (TRα) highlighted the role of canonical TR action. Strikingly, selective abrogation of canonical TR action often had little phenotypic consequence, suggesting that noncanonical TR action sufficed to maintain the wild-type phenotype for specific effects. For instance, macrocytic anemia, reduced retinal vascularization, or increased anxiety-related behavior were only observed in TRαKO but not TRαGS mice. Noncanonical TRα action improved energy utilization and prevented hyperphagia observed in female TRαKO mice. In summary, by examining the phenotypes of TRα and TRβ knockout models alongside their DNA binding-deficient mutants and wild-type counterparts, we could establish that the noncanonical actions of TRα and TRβ play a crucial role in modulating sensory, behavioral, and metabolic functions and, thus, contribute to the spectrum of physiological TH effects.

Mitigation of cisplatin-induced cardiotoxicity by Isorhamnetin: Mechanistic insights into oxidative stress, inflammation, and apoptosis modulation

The flavonoid compound Isorhamnetin (IRMN) is known for its considerable pharmacological properties, which include antioxidant and anti-inflammatory effects, as well as significant protective actions on heart health. However, the potential of IRMN to guard against heart damage caused by cisplatin (CP), a common chemotherapeutic agent, and the specific mechanisms involved, remain unexplored areas. This research was designed to investigate how IRMN counters CP-induced heart toxicity. In our study, mice were orally given IRMN at 50 or 150 mg/kg/day for a week, followed by CP injections (5 mg/kg/day) on the third and sixth days. The animals were euthanized under sodium pentobarbital anesthesia (50 mg/kg, intraperitoneally) on the eighth day to collect blood and heart tissues for further examination. Our findings reveal that IRMN administration significantly reduced the heart damage and the elevation of heart injury markers such as cardiac troponin I, creatine kinase, and lactate dehydrogenase induced by CP. IRMN also effectively lowered oxidative stress markers, including reactive oxygen species and malondialdehyde, while boosting ATP production and antioxidants like superoxide dismutase, catalase, and glutathione. The compound's capability to diminish the levels of pro-inflammatory cytokines like tumor necrosis factor-alpha and interleukin-6, alongside modulating apoptosis-regulating proteins (enhancing Bcl-2 while suppressing Bax and Caspase-3 expression), further underscores its cardioprotective effect. Notably, IRMN modulated the p62-Keap1-Nrf2 signaling pathway, suggesting a mechanism through which it exerts its protective effects against CP-induced cardiac injury. These insights underscore the potential of IRMN as an effective adjunct in cancer therapy, offering a strategy to mitigate the cardiotoxic side effects of cisplatin.

A patient-enriched MEIS1 coding variant causes a restless legs syndrome-like phenotype in mice

Restless legs syndrome (RLS) is a neurological disorder characterized by uncomfortable or unpleasant sensations in the legs during rest periods. To relieve these sensations, patients move their legs, causing sleep disruption. While the pathogenesis of RLS has yet to be resolved, there is a strong genetic association with the MEIS1 gene. A missense variant in MEIS1 is enriched sevenfold in people with RLS compared to non-affected individuals. We generated a mouse line carrying this mutation (p.Arg272His/c.815G>A), referred to herein as Meis1R272H/R272H (Meis1 point mutation), to determine whether it would phenotypically resemble RLS. As women are more prone to RLS, driven partly by an increased risk of developing RLS during pregnancy, we focused on female homozygous mice. We evaluated RLS-related outcomes, particularly sensorimotor behavior and sleep, in young and aged mice. Compared to noncarrier littermates, homozygous mice displayed very few differences. Significant hyperactivity occurred before the lights-on (rest) period in aged female mice, reflecting the age-dependent incidence of RLS. Sensory experiments involving tactile feedback (rotarod, wheel running, and hotplate) were only marginally different. Overall, RLS-like phenomena were not recapitulated except for the increased wake activity prior to rest. This is likely due to the focus on young mice. Nevertheless, the Meis1R272H mouse line is a potentially useful RLS model, carrying a clinically relevant variant and showing an age-dependent phenotype.

Implication of transcription factor FOXD2 dysfunction in syndromic congenital anomalies of the kidney and urinary tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are the predominant cause for chronic kidney disease below age 30 years. Many monogenic forms have been discovered due to comprehensive genetic testing like exome sequencing. However, disease-causing variants in known disease-associated genes only explain a proportion of cases. Here, we aim to unravel underlying molecular mechanisms of syndromic CAKUT in three unrelated multiplex families with presumed autosomal recessive inheritance. Exome sequencing in the index individuals revealed three different rare homozygous variants in FOXD2, encoding a transcription factor not previously implicated in CAKUT in humans: a frameshift in the Arabic and a missense variant each in the Turkish and the Israeli family with segregation patterns consistent with autosomal recessive inheritance. CRISPR/Cas9-derived Foxd2 knockout mice presented with a bilateral dilated kidney pelvis accompanied by atrophy of the kidney papilla and mandibular, ophthalmologic, and behavioral anomalies, recapitulating the human phenotype. In a complementary approach to study pathomechanisms of FOXD2-dysfunction-mediated developmental kidney defects, we generated CRISPR/Cas9-mediated knockout of Foxd2 in ureteric bud-induced mouse metanephric mesenchyme cells. Transcriptomic analyses revealed enrichment of numerous differentially expressed genes important for kidney/urogenital development, including Pax2 and Wnt4 as well as gene expression changes indicating a shift toward a stromal cell identity. Histology of Foxd2 knockout mouse kidneys confirmed increased fibrosis. Further, genome-wide association studies suggest that FOXD2 could play a role for maintenance of podocyte integrity during adulthood. Thus, our studies help in genetic diagnostics of monogenic CAKUT and in understanding of monogenic and multifactorial kidney diseases.

Insights into energy balance dysregulation from a mouse model of methylmalonic aciduria

Inherited disorders of mitochondrial metabolism, including isolated methylmalonic aciduria, present unique challenges to energetic homeostasis by disrupting energy-producing pathways. To better understand global responses to energy shortage, we investigated a hemizygous mouse model of methylmalonyl-CoA mutase (Mmut)-type methylmalonic aciduria. We found Mmut mutant mice to have reduced appetite, energy expenditure and body mass compared with littermate controls, along with a relative reduction in lean mass but increase in fat mass. Brown adipose tissue showed a process of whitening, in line with lower body surface temperature and lesser ability to cope with cold challenge. Mutant mice had dysregulated plasma glucose, delayed glucose clearance and a lesser ability to regulate energy sources when switching from the fed to fasted state, while liver investigations indicated metabolite accumulation and altered expression of peroxisome proliferator-activated receptor and Fgf21-controlled pathways. Together, these shed light on the mechanisms and adaptations behind energy imbalance in methylmalonic aciduria and provide insight into metabolic responses to chronic energy shortage, which may have important implications for disease understanding and patient management.

Monoallelic variation in DHX9, the gene encoding the DExH-box helicase DHX9, underlies neurodevelopment disorders and Charcot-Marie-Tooth disease

DExD/H-box RNA helicases (DDX/DHX) are encoded by a large paralogous gene family; in a subset of these human helicase genes, pathogenic variation causes neurodevelopmental disorder (NDD) traits and cancer. DHX9 encodes a BRCA1-interacting nuclear helicase regulating transcription, R-loops, and homologous recombination and exhibits the highest mutational constraint of all DDX/DHX paralogs but remains unassociated with disease traits in OMIM. Using exome sequencing and family-based rare-variant analyses, we identified 20 individuals with de novo, ultra-rare, heterozygous missense or loss-of-function (LoF) DHX9 variant alleles. Phenotypes ranged from NDDs to the distal symmetric polyneuropathy axonal Charcot-Marie-Tooth disease (CMT2). Quantitative Human Phenotype Ontology (HPO) analysis demonstrated genotype-phenotype correlations with LoF variants causing mild NDD phenotypes and nuclear localization signal (NLS) missense variants causing severe NDD. We investigated DHX9 variant-associated cellular phenotypes in human cell lines. Whereas wild-type DHX9 was restricted to the nucleus, NLS missense variants abnormally accumulated in the cytoplasm. Fibroblasts from an individual with an NLS variant also showed abnormal cytoplasmic DHX9 accumulation. CMT2-associated missense variants caused aberrant nucleolar DHX9 accumulation, a phenomenon previously associated with cellular stress. Two NDD-associated variants, p.Gly411Glu and p.Arg761Gln, altered DHX9 ATPase activity. The severe NDD-associated variant p.Arg141Gln did not affect DHX9 localization but instead increased R-loop levels and double-stranded DNA breaks. Dhx9-/- mice exhibited hypoactivity in novel environments, tremor, and sensorineural hearing loss. All together, these results establish DHX9 as a critical regulator of mammalian neurodevelopment and neuronal homeostasis.

TXNIP overexpression in mice enhances streptozotocin-induced diabetes severity

Thioredoxin-interacting protein (TXNIP) is a key player in the endocrine pancreas; it induces beta cell apoptosis, such that TXNIP deficiency promotes beta cell survival. To study its function in more detail, we generated transgenic mice with ubiquitous overexpression of TXNIP. CBA^TXNIP/+ mice were investigated under basal conditions and after being challenged in diet-induced obesity (DIO) and streptozotocin-induced type 1 diabetes mellitus (T1DM) models. TXNIP overexpression caused no effect in the DIO model, contrasting to the already reported TXNIP-deficient mice. However, in the T1DM background, CBA^TXNIP/+ animals showed significantly enhanced blood glucose and increased glucose levels in a glucose tolerance test. Finally, the beta cell mass of CBA^TXNIP/+ transgenic animals in the T1DM model was significantly reduced compared to control littermates. Our study demonstrates that overexpression of TXNIP doesn't affect blood glucose parameters under basal conditions. However, overexpression of TXNIP in a T1DM model enhances the severity of the disease.

Implication of FOXD2 dysfunction in syndromic congenital anomalies of the kidney and urinary tract (CAKUT)

Background

Congenital anomalies of the kidney and urinary tract (CAKUT) are the predominant cause for chronic kidney disease below 30 years of age. Many monogenic forms have been discovered mainly due to comprehensive genetic testing like exome sequencing (ES). However, disease-causing variants in known disease-associated genes still only explain a proportion of cases. Aim of this study was to unravel the underlying molecular mechanism of syndromic CAKUT in two multiplex families with presumed autosomal recessive inheritance.

Methods and Results

ES in the index individuals revealed two different rare homozygous variants in FOXD2, a transcription factor not previously implicated in CAKUT in humans: a frameshift in family 1 and a missense variant in family 2 with family segregation patterns consistent with autosomal-recessive inheritance. CRISPR/Cas9-derived Foxd2 knock-out (KO) mice presented with bilateral dilated renal pelvis accompanied by renal papilla atrophy while extrarenal features included mandibular, ophthalmologic, and behavioral anomalies, recapitulating the phenotype of humans with FOXD2 dysfunction. To study the pathomechanism of FOXD2-dysfunction-mediated developmental renal defects, in a complementary approach, we generated CRISPR/Cas9-mediated KO of Foxd2 in ureteric-bud-induced mouse metanephric mesenchyme cells. Transcriptomic analyses revealed enrichment of numerous differentially expressed genes important in renal/urogenital development, including Pax2 and Wnt4 as well as gene expression changes indicating a cell identity shift towards a stromal cell identity. Histology of Foxd2 KO mouse kidneys confirmed increased fibrosis. Further, GWAS data (genome-wide association studies) suggests that FOXD2 could play a role for maintenance of podocyte integrity during adulthood.

Conclusions

In summary, our data implicate that FOXD2 dysfunction is a very rare cause of autosomal recessive syndromic CAKUT and suggest disturbances of the PAX2-WNT4 cell signaling axis contribute to this phenotype.

Identifying causal serum protein-cardiometabolic trait relationships using whole genome sequencing

Cardiometabolic diseases, such as type 2 diabetes and cardiovascular disease, have a high public health burden. Understanding the genetically-determined regulation of proteins that are dysregulated in disease can help to dissect the complex biology underpinning them. Here, we perform a protein quantitative trait locus (pQTL) analysis of 255 serum proteins relevant to cardiometabolic processes in 2893 individuals. Meta-analysing whole-genome sequencing (WGS) data from two Greek cohorts, MANOLIS (n = 1356; 22.5x WGS) and Pomak (n = 1537; 18.4x WGS), we detect 302 independently-associated pQTL variants for 171 proteins, including 12 rare variants (minor allele frequency [MAF] < 1%). We additionally find 15 pQTL variants that are rare in non-Finnish European populations, but have drifted up in frequency in the discovery cohorts here. We identify proteins causally associated with cardiometabolic traits, including MEP1B for high-density lipoprotein levels; and describe a knock-out Mep1b mouse model. Our findings furnish insights into the genetic architecture of the serum proteome, identify new protein-disease relationships, and demonstrate the importance of isolated populations in pQTL analysis.

Dietary intervention improves health metrics and life expectancy of the genetically obese Titan mouse

Suitable animal models are essential for translational research, especially in the case of complex, multifactorial conditions, such as obesity. The non-inbred mouse (Mus musculus) line Titan, also known as DU6, is one of the world’s longest selection experiments for high body mass and was previously described as a model for metabolic healthy (benign) obesity. The present study further characterizes the geno- and phenotypes of this non-inbred mouse line and tests its suitability as an interventional obesity model. In contrast to previous findings, our data suggest that Titan mice are metabolically unhealthy obese and short-lived. Line-specific patterns of genetic invariability are in accordance with observed phenotypic traits. Titan mice also show modifications in the liver transcriptome, proteome, and epigenome linked to metabolic (dys)regulations. Importantly, dietary intervention partially reversed the metabolic phenotype in Titan mice and significantly extended their life expectancy. Therefore, the Titan mouse line is a valuable resource for translational and interventional obesity research.

This study further characterizes the non-inbred Titan (also known as DU6) mouse line, which could be a useful model for obesity research.

Mice lacking the mitochondrial exonuclease MGME1 develop inflammatory kidney disease with glomerular dysfunction

Mitochondrial DNA (mtDNA) maintenance disorders are caused by mutations in ubiquitously expressed nuclear genes and lead to syndromes with variable disease severity and tissue-specific phenotypes. Loss of function mutations in the gene encoding the mitochondrial genome and maintenance exonuclease 1 (MGME1) result in deletions and depletion of mtDNA leading to adult-onset multisystem mitochondrial disease in humans. To better understand the in vivo function of MGME1 and the associated disease pathophysiology, we characterized a Mgme1 mouse knockout model by extensive phenotyping of ageing knockout animals. We show that loss of MGME1 leads to de novo formation of linear deleted mtDNA fragments that are constantly made and degraded. These findings contradict previous proposal that MGME1 is essential for degradation of linear mtDNA fragments and instead support a model where MGME1 has a critical role in completion of mtDNA replication. We report that Mgme1 knockout mice develop a dramatic phenotype as they age and display progressive weight loss, cataract and retinopathy. Surprisingly, aged animals also develop kidney inflammation, glomerular changes and severe chronic progressive nephropathy, consistent with nephrotic syndrome. These findings link the faulty mtDNA synthesis to severe inflammatory disease and thus show that defective mtDNA replication can trigger an immune response that causes age-associated progressive pathology in the kidney.

We have addressed the controversy of the role of the mitochondrial genome and maintenance exonuclease 1 (MGME1) in mtDNA metabolism by characterization of knockout mice. Our findings show that loss of MGME1 leads to increased de novo formation of linear deleted mtDNA, thus contradicting previous report that MGME1 degrades long linear mtDNA molecules. In addition, we report that loss of MGME1 leads to age-associated pathology manifested as progressive weight loss, cataract and retinopathy. Aged knockout mice also develop kidney inflammation leading to glomerular changes, fibrosis and nephrotic syndrome. Defective mtDNA replication causing the formation of linear deleted mtDNA can thus trigger an immune response that leads to the development of progressive kidney disease in ageing animals.

Post-synaptic scaffold protein TANC2 in psychiatric and somatic disease risk

Understanding the shared genetic aetiology of psychiatric and medical comorbidity in neurodevelopmental disorders (NDDs) could improve patient diagnosis, stratification and treatment options. Rare tetratricopeptide repeat, ankyrin repeat and coiled-coil containing 2 (TANC2)-disrupting variants were disease causing in NDD patients. The post-synaptic scaffold protein TANC2 is essential for dendrite formation in synaptic plasticity and plays an unclarified but critical role in development. We here report a novel homozygous-viable Tanc2-disrupted function model in which mutant mice were hyperactive and had impaired sensorimotor gating consistent with NDD patient psychiatric endophenotypes. Yet, a multi-systemic analysis revealed the pleiotropic effects of Tanc2 outside the brain, such as growth failure and hepatocellular damage. This was associated with aberrant liver function including altered hepatocellular metabolism. Integrative analysis indicates that these disrupted Tanc2 systemic effects relate to interaction with Hippo developmental signalling pathway proteins and will increase the risk for comorbid somatic disease. This highlights how NDD gene pleiotropy can augment medical comorbidity susceptibility, underscoring the benefit of holistic NDD patient diagnosis and treatment for which large-scale preclinical functional genomics can provide complementary pleiotropic gene function information.

Summary: Disruption of mouse Tanc2 causes brain and liver abnormality, increasing psychiatric and somatic disease risk long term, highlighting the benefit of holistic diagnosis and treatment approaches for human neurodevelopmental disorder.

Characterising a homozygous two-exon deletion in UQCRH: comparing human and mouse phenotypes

Mitochondrial disorders are clinically and genetically diverse, with isolated complex III (CIII) deficiency being relatively rare. Here, we describe two affected cousins, presenting with recurrent episodes of severe lactic acidosis, hyperammonaemia, hypoglycaemia and encephalopathy. Genetic investigations in both cases identified a homozygous deletion of exons 2 and 3 of UQCRH, which encodes a structural complex III (CIII) subunit. We generated a mouse model with the equivalent homozygous Uqcrh deletion (Uqcrh-/- ), which also presented with lactic acidosis and hyperammonaemia, but had a more severe, non-episodic phenotype, resulting in failure to thrive and early death. The biochemical phenotypes observed in patient and Uqcrh-/- mouse tissues were remarkably similar, displaying impaired CIII activity, decreased molecular weight of fully assembled holoenzyme and an increase of an unexpected large supercomplex (SXL ), comprising mostly of one complex I (CI) dimer and one CIII dimer. This phenotypic similarity along with lentiviral rescue experiments in patient fibroblasts verifies the pathogenicity of the shared genetic defect, demonstrating that the Uqcrh-/- mouse is a valuable model for future studies of human CIII deficiency.

Nox4 Maintains Blood Pressure during Low Sodium Diet

The NADPH oxidase Nox4 is a hydrogen peroxide (H₂O₂)-producing enzyme, with the highest expression in the kidney. As the kidney is involved in volume and blood pressure control through sodium handling, we set out to determine the impact of a low sodium diet on these parameters in WT and Nox4-/- mice. Nox4 expression in the murine kidney was restricted to the proximal tubule. Nevertheless, low-sodium-induced weight loss and sodium sparing function was similar in WT and Nox4-/- mice, disputing an important function of renal Nox4 in sodium handling. In contrast, a low sodium diet resulted in a reduction in systolic blood pressure in Nox4-/- as compared to WT mice. This was associated with a selectively lower pressure to heart-rate ratio, as well as heart to body weight ratio. In general, a low sodium diet leads to activation of sympathetic tone and the renin angiotensin system, which subsequently increases peripheral resistance. Our observations suggest that the control by this system is attenuated in Nox4-/- mice, resulting in lower blood pressure in response to low sodium.

A comprehensive phenotypic characterization of a whole-body Wdr45 knock-out mouse

Pathogenic variants in the WDR45 (OMIM: 300,526) gene on chromosome Xp11 are the genetic cause of a rare neurological disorder characterized by increased iron deposition in the basal ganglia. As WDR45 encodes a beta-propeller scaffold protein with a putative role in autophagy, the disease has been named Beta-Propeller Protein-Associated Neurodegeneration (BPAN). BPAN represents one of the four most common forms of Neurodegeneration with Brain Iron Accumulation (NBIA). In the current study, we generated and characterized a whole-body Wdr45 knock-out (KO) mouse model. The model, developed using TALENs, presents a 20-bp deletion in exon 2 of Wdr45. Homozygous females and hemizygous males are viable, proving that systemic depletion of Wdr45 does not impair viability and male fertility in mice. The in-depth phenotypic characterization of the mouse model revealed neuropathology signs at four months of age, neurodegeneration progressing with ageing, hearing and visual impairment, specific haematological alterations, but no brain iron accumulation. Biochemically, Wdr45 KO mice presented with decreased complex I (CI) activity in the brain, suggesting that mitochondrial dysfunction accompanies Wdr45 deficiency. Overall, the systemic Wdr45 KO described here complements the two mouse models previously reported in the literature (PMIDs: 26,000,824, 31,204,559) and represents an additional robust model to investigate the pathophysiology of BPAN and to test therapeutic strategies for the disease.

PAX6 mutation alters circadian rhythm and β cell function in mice without affecting glucose tolerance

The transcription factor PAX6 is involved in the development of the eye and pancreatic islets, besides being associated with sleep–wake cycles. Here, we investigated a point mutation in the RED subdomain of PAX6, previously described in a human patient, to present a comprehensive study of a homozygous Pax6 mutation in the context of adult mammalian metabolism and circadian rhythm. Pax6^Leca2 mice lack appropriate retinal structures for light perception and do not display normal daily rhythmic changes in energy metabolism. Despite β cell dysfunction and decreased insulin secretion, mutant mice have normal glucose tolerance. This is associated with reduced hepatic glucose production possibly due to altered circadian variation in expression of clock and metabolic genes, thereby evading hyperglycemia. Hence, our findings show that while the RED subdomain is important for β cell functional maturity, the Leca2 mutation impacts peripheral metabolism via loss of circadian rhythm, thus revealing pleiotropic effects of PAX6.

Nirav Chhabra et al. characterize adult mice carrying a homozygous mutation in Pax6 that was identified in a patient with foveal hypoplasia. They find that the Pax6 point mutation has pleiotropic effects, including defects in the mouse retinal structures, loss of the optic nerve, changes in energy metabolism and circadian rhythms, and dysregulation of genes expressed in the pancreas.

Phosphorylation Control of p53 DNA-Binding Cooperativity Balances Tumorigenesis and Aging

Posttranslational modifications are essential for regulating the transcription factor p53, which binds DNA in a highly cooperative manner to control expression of a plethora of tumor-suppressive programs. Here we show at the biochemical, cellular, and organismal level that the cooperative nature of DNA binding is reduced by phosphorylation of highly conserved serine residues (human S183/S185, mouse S180) in the DNA-binding domain. To explore the role of this inhibitory phosphorylation in vivo, new phosphorylation-deficient p53-S180A knock-in mice were generated. Chromatin immunoprecipitation sequencing and RNA sequencing studies of S180A knock-in cells demonstrated enhanced DNA binding and increased target gene expression. In vivo, this translated into a tissue-specific vulnerability of the bone marrow that caused depletion of hematopoietic stem cells and impaired proper regeneration of hematopoiesis after DNA damage. Median lifespan was significantly reduced by 20% from 709 days in wild type to only 568 days in S180A littermates. Importantly, lifespan was reduced by a loss of general fitness and increased susceptibility to age-related diseases, not by increased cancer incidence as often seen in other p53-mutant mouse models. For example, S180A knock-in mice showed markedly reduced spontaneous tumorigenesis and increased resistance to Myc-driven lymphoma and Eml4-Alk-driven lung cancer. Preventing phosphorylation of S183/S185 in human cells boosted p53 activity and allowed tumor cells to be killed more efficiently. Together, our data identify p53 DNA-binding domain phosphorylation as a druggable mechanism that balances tumorigenesis and aging. SIGNIFICANCE: These findings demonstrate that p53 tumor suppressor activity is reduced by DNA-binding domain phosphorylation to prevent aging and identify this phosphorylation as a potential target for cancer therapy.See related commentary by Horikawa, p. 5164.

METTL6 is a tRNA m3C methyltransferase that regulates pluripotency and tumor cell growth

Recently, covalent modifications of RNA, such as methylation, have emerged as key regulators of all aspects of RNA biology and have been implicated in numerous diseases, for instance, cancer. Here, we undertook a combination of in vitro and in vivo screens to test 78 potential methyltransferases for their roles in hepatocellular carcinoma (HCC) cell proliferation. We identified methyltransferase-like protein 6 (METTL6) as a crucial regulator of tumor cell growth. We show that METTL6 is a bona fide transfer RNA (tRNA) methyltransferase, catalyzing the formation of 3-methylcytidine at C32 of specific serine tRNA isoacceptors. Deletion of Mettl6 in mouse stem cells results in changes in ribosome occupancy and RNA levels, as well as impaired pluripotency. In mice, Mettl6 knockout results in reduced energy expenditure. We reveal a previously unknown pathway in the maintenance of translation efficiency with a role in maintaining stem cell self-renewal, as well as impacting tumor cell growth profoundly.

Effect of Gallic acid and Myricetin on ovarian cancer models: a possible alternative antitumoral treatment

Background

Ovarian cancer is the leading cause of mortality among malignant gynecological tumors. Surgical resection and chemotherapy with intravenous platinum/taxanes drugs are the treatments of choice, with little effectiveness in later stages and severe toxicological effects. Therefore, this study aimed to evaluate the antineoplastic activity of gallic acid (GA) and myricetin (Myr) administrated peritumorally in Nu/Nu mice xenotransplanted with SKOV-3 cells.

Methods

Biological activity of GA and MYR was evaluated in SKOV-3 and OVCAR-3 cells (ovarian adenocarcinomas) by confocal/transmission electron microscopy, PI-flow cytometry, H₂-DCF-DA stain, MTT, and Annexin V/PI assays. Molecular targets of compounds were determined with ACD/I-Labs and SEA. Antineoplastic activity was performed in SKOV-3 cells subcutaneously xenotransplanted into female Nu/Nu mice treated peritumorally with 50 mg/kg of each compound (2 alternate days/week) for 28 days. Controls used were paclitaxel (5 mg/kg) and 20 μL of vehicle (0.5% DMSO in 1X PBS). Tumor lesions, organs and sera were evaluated with NMR, USG, histopathological, and paraclinical studies.

Results

In vitro studies showed a decrease of cell viability with GA and Myr in SKOV-3 (50 and 166 μg/mL) and OVCAR-3 (43 and 94 μg/mL) cells respectively, as well as morphological changes, cell cycle arrest, and apoptosis induction due to ROS generation (p ≤ 0.05, ANOVA). In silico studies suggest that GA and MYR could interact with carbonic anhydrase IX and PI3K, respectively. In vivo studies revealed inhibitory effects on tumor lesions development with GA and MYR up to 50% (p ≤ 0.05, ANOVA), with decreased vascularity, necrotic/fibrotic areas, neoplastic stroma retraction and apoptosis. However, toxicological effects were observed with GA treatment, such as leukocyte infiltrate and hepatic parenchyma loss, hypertransaminasemia (ALT: 150.7 ± 25.60 U/L), and hypoazotemia (urea: 33.4 ± 7.4 mg/dL), due to the development of chronic hepatitis (p ≤ 0.05, ANOVA).

Conclusion

GA and Myr (50 mg/kg) administered by peritumoral route, inhibit ovarian tumor lesions development in rodents with some toxicological effects. Additional studies will be necessary to find the appropriate therapeutic dose for GA. Therefore, GA and Myr could be considered as a starting point for the development of novel anticancer agents.

Functional changes of the liver in the absence of growth hormone (GH) action - Proteomic and metabolomic insights from a GH receptor deficient pig model

OBJECTIVE

The liver is a central target organ of growth hormone (GH), which stimulates the synthesis of insulin-like growth factor 1 (IGF1) and affects multiple biochemical pathways. A systematic multi-omics analysis of GH effects in the liver has not been performed. GH receptor (GHR) deficiency is a unique model for studying the consequences of lacking GH action. In this study, we used molecular profiling techniques to capture a broad spectrum of these effects in the liver of a clinically relevant large animal model for Laron syndrome.

METHODS

We performed holistic proteome and targeted metabolome analyses of liver samples from 6-month-old GHR-deficient (GHR-KO) pigs and GHR-expressing controls (four males, four females per group).

RESULTS

GHR deficiency resulted in an increased abundance of enzymes involved in amino acid degradation, in the urea cycle, and in the tricarboxylic acid cycle. A decreased ratio of long-chain acylcarnitines to free carnitine suggested reduced activity of carnitine palmitoyltransferase 1A and thus reduced mitochondrial import of fatty acids for beta-oxidation. Increased levels of short-chain acylcarnitines in the liver and in the circulation of GHR-KO pigs may result from impaired beta-oxidation of short-chain fatty acids or from increased degradation of specific amino acids. The concentration of mono-unsaturated glycerophosphocholines was significantly increased in the liver of GHR-KO pigs without morphological signs of steatosis, although the abundances of several proteins functionally linked to non-alcoholic fatty liver disease (fetuin B, retinol binding protein 4, several mitochondrial proteins) were increased. Moreover, GHR-deficient liver samples revealed distinct changes in the methionine and glutathione metabolic pathways, in particular, a significantly increased level of glycine N-methyltransferase and increased levels of total and free glutathione. Several proteins revealed a sex-related abundance difference in the control group but not in the GHR-KO group.

CONCLUSIONS

Our integrated proteomics/targeted metabolomics study of GHR-deficient and control liver samples from a clinically relevant large animal model identified a spectrum of biological pathways that are significantly altered in the absence of GH action. Moreover, new insights into the role of GH in the sex-related specification of liver functions were provided.

In-depth phenotyping reveals common and novel disease symptoms in a hemizygous knock-in mouse model (Mut-ko/ki) of mut-type methylmalonic aciduria

Isolated methylmalonic aciduria (MMAuria) is primarily caused by deficiency of methylmalonyl-CoA mutase (MMUT or MUT). Biochemically, MUT deficiency results in the accumulation of methylmalonic acid (MMA), propionyl-carnitine (C3) and other metabolites. Patients often exhibit lethargy, failure to thrive and metabolic decompensation leading to coma or even death, with kidney and neurological impairment frequently identified in the long-term. Here, we report a hemizygous mouse model which combines a knock-in (ki) missense allele of Mut with a knock-out (ko) allele (Mut-ko/ki mice) that was fed a 51%-protein diet from day 12 of life, constituting a bespoke model of MMAuria. Under this diet, mutant mice developed a pronounced metabolic phenotype characterized by drastically increased blood levels of MMA and C3 compared to their littermate controls (Mut-ki/wt). With this bespoke mouse model, we performed a standardized phenotypic screen to assess the whole-body impairments associated with this strong metabolic condition. We found that Mut-ko/ki mice show common clinical manifestations of MMAuria, including pronounced failure to thrive, indications of mild neurological and kidney dysfunction, and degenerative morphological changes in the liver, along with less well described symptoms such as cardiovascular and hematological abnormalities. The analyses also reveal so far unknown disease characteristics, including low bone mineral density, anxiety-related behaviour and ovarian atrophy. This first phenotypic screening of a MMAuria mouse model confirms its relevance to human disease, reveals new alterations associated with MUT deficiency, and suggests a series of quantifiable readouts that can be used to evaluate potential treatment strategies.

Analogs of penfluridol as chemotherapeutic agents with reduced central nervous system activity

Several recent reports have highlighted the feasibility of the use of penfluridol, a well-known antipsychotic agent, as a chemotherapeutic agent. In vivo experiments have confirmed the cytotoxic activity of penfluridol in triple-negative breast cancer model, lung cancer model, and further studies have been proposed to assess its anticancer activity and viability for the treatment of glioblastomas. However, penfluridol anticancer activity was observed at a dosage significantly higher than that administered in antipsychotic therapy, thus raising the concern for the potential onset of CNS side effects in patients undergoing intensive pharmacological treatment. In this study, we evaluate the potential CNS toxicity of penfluridol side by side with a set of analogs.

Meis1: effects on motor phenotypes and the sensorimotor system in mice

MEIS1 encodes a developmental transcription factor and has been linked to restless legs syndrome (RLS) in genome-wide association studies. RLS is a movement disorder leading to severe sleep reduction and has a substantial impact on the quality of life of patients. In genome-wide association studies, MEIS1 has consistently been the gene with the highest effect size and functional studies suggest a disease-relevant downregulation. Therefore, haploinsufficiency of Meis1 could be the system with the most potential for modeling RLS in animals. We used heterozygous Meis1-knockout mice to study the effects of Meis1 haploinsufficiency on mouse behavioral and neurological phenotypes, and to relate the findings to human RLS. We exposed the Meis1-deficient mice to assays of motor, sensorimotor and cognitive ability, and assessed the effect of a dopaminergic receptor 2/3 agonist commonly used in the treatment of RLS. The mutant mice showed a pattern of circadian hyperactivity, which is compatible with human RLS. Moreover, we discovered a replicable prepulse inhibition (PPI) deficit in the Meis1-deficient animals. In addition, these mice were hyposensitive to the PPI-reducing effect of the dopaminergic receptor agonist, highlighting a role of Meis1 in the dopaminergic system. Other reported phenotypes include enhanced social recognition at an older age that was not related to alterations in adult olfactory bulb neurogenesis previously shown to be implicated in this behavior. In conclusion, the Meis1-deficient mice fulfill some of the hallmarks of an RLS animal model, and revealed the role of Meis1 in sensorimotor gating and in the dopaminergic systems modulating it.

Summary: Loss of Meis1 results in motor restlessness in mice, a phenotype resembling human restless legs syndrome, as well as altered sensorimotor gating and improved social discrimination memory.

Genetic characterization of a mouse line with primary aldosteronism

In an attempt to define novel genetic loci involved in the pathophysiology of primary aldosteronism, a mutagenesis screen after treatment with the alkylating agent N-ethyl-N-nitrosourea was established for the parameter aldosterone. One of the generated mouse lines with hyperaldosteronism was phenotypically and genetically characterized. This mouse line had high aldosterone levels but normal creatinine and urea values. The steroidogenic enzyme expression levels in the adrenal gland did not differ significantly among phenotypically affected and unaffected mice. Upon exome sequencing, point mutations were identified in seven candidate genes (Sspo, Dguok, Hoxaas2, Clstn3, Atm, Tipin and Mapk6). Subsequently, animals were stratified into wild-type and mutated groups according to their genotype for each of these candidate genes. A correlation of their genotypes with the respective aldosterone, aldosterone-to-renin ratio (ARR), urea and creatinine values as well as steroidogenic enzyme expression levels was performed. Aldosterone values were significantly higher in animals carrying mutations in four different genes (Sspo, Dguok, Hoxaas2 and Clstn3) and associated statistically significant adrenal Cyp11b2 overexpression as well as increased ARR was present only in mice with Sspo mutation. In contrast, mutations of the remaining candidate genes (Atm, Tipin and Mapk6) were associated with lower aldosterone values and lower Hsd3b6 expression levels. In summary, these data demonstrate association between the genes Sspo, Dguok, Hoxaas2 and Clstn3 and hyperaldosteronism. Final proofs for the causative nature of the mutations have to come from knock-out and knock-in experiments.

Bezafibrate ameliorates diabetes via reduced steatosis and improved hepatic insulin sensitivity in diabetic TallyHo mice

OBJECTIVE

Recently, we have shown that Bezafibrate (BEZ), the pan-PPAR (peroxisome proliferator-activated receptor) activator, ameliorated diabetes in insulin deficient streptozotocin treated diabetic mice. In order to study whether BEZ can also improve glucose metabolism in a mouse model for fatty liver and type 2 diabetes, the drug was applied to TallyHo mice.

METHODS

TallyHo mice were divided into an early (ED) and late (LD) diabetes progression group and both groups were treated with 0.5% BEZ (BEZ group) or standard diet (SD group) for 8 weeks. We analyzed plasma parameters, pancreatic beta-cell morphology, and mass as well as glucose metabolism of the BEZ-treated and control mice. Furthermore, liver fat content and composition as well as hepatic gluconeogenesis and mitochondrial mass were determined.

RESULTS

Plasma lipid and glucose levels were markedly reduced upon BEZ treatment, which was accompanied by elevated insulin sensitivity index as well as glucose tolerance, respectively. BEZ increased islet area in the pancreas. Furthermore, BEZ treatment improved energy expenditure and metabolic flexibility. In the liver, BEZ ameliorated steatosis, modified lipid composition and increased mitochondrial mass, which was accompanied by reduced hepatic gluconeogenesis.

CONCLUSIONS

Our data showed that BEZ ameliorates diabetes probably via reduced steatosis, enhanced hepatic mitochondrial mass, improved metabolic flexibility and elevated hepatic insulin sensitivity in TallyHo mice, suggesting that BEZ treatment could be beneficial for patients with NAFLD and impaired glucose metabolism.

Serum Response Factor (SRF) Ablation Interferes with Acute Stress-Associated Immediate and Long-Term Coping Mechanisms

Stress experience modulates behavior, metabolism, and energy expenditure of organisms. One molecular hallmark of an acute stress response is a rapid induction of immediate early genes (IEGs) such as c-Fos and Egr family members. IEG transcription in neurons is mediated by the neuronal activity-driven gene regulator serum response factor (SRF). We show a first role of SRF in immediate and long-lasting acute restraint stress (AS) responses. For this, we employed a standardized mouse phenotyping protocol at the German Mouse Clinic (GMC) including behavioral, metabolic, and cardiologic tests as well as gene expression profiling to analyze the consequences of forebrain-specific SRF deletion in mice exposed to AS. Adult mice with an SRF deletion in glutamatergic neurons (Srf; ^{CaMKIIa-CreERT2} ) showed hyperactivity, decreased anxiety, and impaired working memory. In response to restraint AS, instant stress reactivity including locomotor behavior and corticosterone induction was impaired in Srf mutant mice. Interestingly, even several weeks after previous AS exposure, SRF-deficient mice showed long-lasting AS-associated changes including altered locomotion, metabolism, energy expenditure, and cardiovascular changes. This suggests a requirement of SRF for mediating long-term stress coping mechanisms in wild-type mice. SRF ablation decreased AS-mediated IEG induction and activity of the actin severing protein cofilin. In summary, our data suggest an SRF function in immediate AS reactions and long-term post-stress-associated coping mechanisms.

A Mouse Model of Furosemide-Induced Overactive Bladder

Detailed in this unit is a mouse model of overactive bladder and urinary incontinence based on diuretic stress-induced urination. The procedure involves the use of a unique, highly sensitive, and automated urine capturing method to measure urinary latency, frequency, and void volume. Although this method was first described and validated using an anti-muscarinic drug used for treating overactive bladder, subsequent work has shown that effective non-cholinergic agents can be detected. These findings indicate good predictive value for this model regarding the possible clinical utility of test agents as treatments for overactive bladder, regardless of their site of action. © 2016 by John Wiley & Sons, Inc.

Oxalate-induced chronic kidney disease with its uremic and cardiovascular complications in C57BL/6 mice

Chronic kidney disease (CKD) research is limited by the lack of convenient inducible models mimicking human CKD and its complications in experimental animals. We demonstrate that a soluble oxalate-rich diet induces stable stages of CKD in male and female C57BL/6 mice. Renal histology is characterized by tubular damage, remnant atubular glomeruli, interstitial inflammation, and fibrosis, with the extent of tissue involvement depending on the duration of oxalate feeding. Expression profiling of markers and magnetic resonance imaging findings established to reflect inflammation and fibrosis parallel the histological changes. Within 3 wk, the mice reproducibly develop normochromic anemia, metabolic acidosis, hyperkalemia, FGF23 activation, hyperphosphatemia, and hyperparathyroidism. In addition, the model is characterized by profound arterial hypertension as well as cardiac fibrosis that persist following the switch to a control diet. Together, this new model of inducible CKD overcomes a number of previous experimental limitations and should serve useful in research related to CKD and its complications.

Glucose tolerance tests for systematic screening of glucose homeostasis in mice

This article presents a detailed description of intraperitoneal and oral glucose tolerance tests in mice. The former is widely used in initial high-throughput phenotyping of mutant mice to assess a diabetic phenotype and alterations in glucose homeostasis. Each protocol provides a comprehensive description of each step in the workflow, including variation of the standard protocol under particular circumstances (e.g., sensitivity to food deprivation, excessive deviations in body composition, or need for extra blood samples for additional analyses). We also describe how reduction of body mass and body temperature can be used as additional readouts to monitor metabolic function in response to food deprivation.

Pleiotropic functions for transcription factor zscan10

The transcription factor Zscan10 had been attributed a role as a pluripotency factor in embryonic stem cells based on its interaction with Oct4 and Sox2 in in vitro assays. Here we suggest a potential role of Zscan10 in controlling progenitor cell populations in vivo. Mice homozygous for a Zscan10 mutation exhibit reduced weight, mild hypoplasia in the spleen, heart and long bones and phenocopy an eye malformation previously described for Sox2 hypomorphs. Phenotypic abnormalities are supported by the nature of Zscan10 expression in midgestation embryos and adults suggesting a role for Zscan10 in either maintaining progenitor cell subpopulation or impacting on fate choice decisions thereof.

No amelioration of uromodulin maturation and trafficking defect by sodium 4-phenylbutyrate in vivo: studies in mouse models of uromodulin-associated kidney disease

Uromodulin (UMOD)-associated kidney disease (UAKD) belongs to the hereditary progressive ER storage diseases caused by maturation defects of mutant UMOD protein. Current treatments of UAKD patients are symptomatic and cannot prevent disease progression. Two in vitro studies reported a positive effect of the chemical chaperone sodium 4-phenylbutyrate (4-PBA) on mutant UMOD maturation. Thus, 4-PBA was suggested as a potential treatment for UAKD. This study evaluated the effects of 4-PBA in two mouse models of UAKD. In contrast to previous in vitro studies, treatment with 4-PBA did not increase HSP70 expression or improve maturation and trafficking of mutant UMOD in vivo. Kidney function of UAKD mice was actually deteriorated by 4-PBA treatment. In transfected tubular epithelial cells, 4-PBA did not improve maturation but increased the expression level of both mutant and wild-type UMOD protein. Activation of NF-κB pathway in thick ascending limb of Henle's loop cells of UAKD mice was detected by increased abundance of RelB and phospho-IκB kinase α/β, an indirect activator of NF-κB. Furthermore, the abundance of NF-κB1 p105/p50, NF-κB2 p100/p52, and TRAF2 was increased in UAKD. NF-κB activation was identified as a novel disease mechanism of UAKD and might be a target for therapeutic intervention.

Evaluation of Rett Syndrome Symptom Improvement by Metabolic Modulators in Mecp2-Mutant Mice

Mouse models recapitulate many symptoms of Rett Syndrome, an X-linked disorder caused by mutations in methyl-CpG-binding protein 2 (MECP2). The study of Mecp2-null male mice has provided insight into pathogenesis of the disorder-most recently, dysregulation of cholesterol and lipid metabolism. Perisymptomatic treatment with statin drugs successfully mitigates the effects of this metabolic syndrome, increases longevity, and improves motor function. Described here is a metabolic drug screening protocol and timeline for symptom evaluation in Mecp2-mutant mice. Specifically, mice are treated twice weekly with a compound of interest alongside subjective health assessments, bi-weekly body composition measurements, and blood chemistries. Throughout treatment, behavioral phenotyping tests are carried out at specific time points. This protocol is highly adaptable to other neurological diseases; however, the time for completion depends on the specific mutant model under study. The protocol highlights the use of techniques described in several different Current Protocols in Mouse Biology articles to carry out testing in a preclinical model. Curr. Protoc. Mouse Biol. 3:187-204 © 2013 by John Wiley & Sons, Inc.

Blood Collection from Mice and Hematological Analyses on Mouse Blood

Basic phenotyping of inbred mouse strains and genetically modified mouse models usually includes the determination of blood-based parameters as a diagnostic screen for genotype effects on metabolism and organ function. A broad range of analytes, including hematological parameters, can be reliably determined in mouse blood, if appropriate samples are available. Here we describe recommended techniques for blood collection from mice and the considerations that have to be taken into account to get adequate samples for hematological investigations. Furthermore, we describe established methods used in the German Mouse Clinic (GMC) to determine hematological parameters in the mouse. Curr. Protoc. Mouse Biol. 3:101-119 © 2013 by John Wiley & Sons, Inc.