Mutational burden of XPNPEP3 leads to defects in mitochondrial complex I and cilia in NPHPL1

Metabolic reprogramming in polycystic kidney disease and other renal ciliopathies

Primary cilia are solitary organelles formed by a microtubule-based skeleton protruding in a single copy on the surface of most cells. Alterations in their function cause a plethora of human conditions collectively called the ciliopathies. The kidney is frequently and severely affected in the ciliopathies, presenting with a spectrum of phenotypes. Cyst formation is a common trait of all renal ciliopathies. Besides this common manifestation, however, the renal ciliopathies present with profoundly different phenotypes, resulting in either polycystic kidney disease (PKD) or nephronophthisis (NPH) phenotypes. The past decade has seen a surge of studies highlighting metabolic reprogramming as a major feature of PKD, with a distinct involvement of mitochondrial dysfunction. This discovery has brought forward the development of novel therapeutic approaches. More recent evidence suggests that primary cilia modulate the mitochondrial production of energy in response to environmental cues. Here, we summarize the evidence available to date and propose a more general involvement of metabolic and mitochondrial alterations in the renal ciliopathies that might in principle help defining the profoundly different, and potentially opposite, manifestations observed.

Mitochondrial proteases modulate mitochondrial stress signalling and cellular homeostasis in health and disease

Maintenance of mitochondrial homeostasis requires a plethora of coordinated quality control and adaptations' mechanisms in which mitochondrial proteases play a key role. Their activation or loss of function reverberate beyond local mitochondrial biochemical and metabolic remodelling into coordinated cellular pathways and stress responses that feedback onto the mitochondrial functionality and adaptability. Mitochondrial proteolysis modulates molecular and organellar quality control, metabolic adaptations, lipid homeostasis and regulates transcriptional stress responses. Defective mitochondrial proteolysis results in disease conditions most notably, mitochondrial diseases, neurodegeneration and cancer. Here, it will be discussed how mitochondrial proteases and mitochondria stress signalling impact cellular homeostasis and determine the cellular decision to survive or die, how these processes may impact disease etiopathology, and how modulation of proteolysis may offer novel therapeutic strategies.

Novel mutation in XPNPEP3 in a patient with heart failure without nephronophthisis-like nephropathy (NPHPL1): case report and literature review

BACKGROUND X-PROLYL AMINOPEPTIDASE 3: (XPNPEP3) mutations are known to cause nephronophthisis-like nephropathy-1 (NPHPL1), a rare autosomal-recessive kidney disease characterized by progressive kidney failure and cystic kidney disease in childhood. The full phenotypic spectrum associated with mutations in XPNPEP3 is not fully elucidated. CASE PRESENTATION: A 13-year-old Chinese female patient with intellectual disability presented with a 2-year history of convulsions and fatigue, with a recent episode of swelling, breathlessness, and nocturnal dyspnea lasting 10 days. The patient was diagnosed with heart failure and kidney failure. Whole exome sequencing revealed a homozygous c.970-2 A > G mutation in XPNPEP3 associated with severe cardiac dysfunction and neurological symptoms, including epilepsy and intellectual disability. Notably, kidney ultrasound did not reveal the typical changes of NPHPL1, and kidney failure was hypothesized to be secondary to cardiac dysfunction rather than primary kidney pathology. CONCLUSIONS: This case suggests the possible association of additional phenotypic features associated with XPNPEP3 mutations, emphasizing the need for further investigation into the heterogeneous clinical presentations associated with XPNPEP3 mutations. The findings highlight the importance of considering alternative phenotypes in patients with genetic mutations traditionally associated with specific diseases. Segregation and functional analyses are necessary to determine causality between the c.970-2 A > G XPNPEP3 mutation and disease.

Comprehensive analysis of the differential expression of mRNAs, lncRNAs, and miRNAs in Zi goose testis with high and low sperm mobility

Sperm mobility (SM) is an objective index for measuring sperm motility; however, the mechanisms underlying its regulation in geese remain unclear. The present study sought to elucidate the genetic mechanism underlying SM traits in Zi geese (Anser cygnoides L.). To this end, three successive experiments were performed. In Experiment I, SM was determined in 40 ganders; the 3 ganders with the highest mobility and three with the lowest mobility were assigned to the high and low sperm mobility rank (SMR) groups, respectively. In Experiment II, the differences in fertility between the two SMR groups were assessed within two breeding flocks comprising the selected six ganders from Experiment I and 30 females (each flock had 3 ganders and 15 females). In Experiment III, the testes of the 6 ganders were harvested for histological observation and whole-transcriptome sequencing. Results revealed better fertility, well-developed seminiferous tubules, and abundant mature sperm in the high-SMR-flock compared to those of the low-SMR-flock (89 vs. 81%) (P < 0.05). Differential expression (DE) analysis identified 76 mRNAs, 344 lncRNAs, and 17 miRNAs between the SMR groups, with LOC106049708, XPNPEP3, GNB3, ADCY8, PRKAG3, oha-miR-182-5p, and ocu-miR-10b-5p identified as key mRNAs and miRNAs contributing to SM. Enrichment analysis implicated these DE RNAs in pathways related to ATP binding, cell metabolism, apelin signaling, Wnt signaling, and Adherens junctions. Additionally, competing endogenous RNA (ceRNA) networks comprising 9 DE mRNAs, 17 DE miRNAs, and 169 DE lncRNAs were constructed. Two ceRNA network pathways (LOC106049708-oha-miR-182-5p-MSTRG.2479.6 and PRKAG3-ocu-miR-10b-5p-MSTRG.9047.14) were identified as key regulators of SM in geese. These findings offer crucial insights into the identification of key genes and ceRNA pathways influencing sperm mobility in geese.

Focus on Mitochondrial Respiratory Chain: Potential Therapeutic Target for Chronic Renal Failure

The function of the respiratory chain is closely associated with kidney function, and the dysfunction of the respiratory chain is a primary pathophysiological change in chronic kidney failure. The incidence of chronic kidney failure caused by defects in respiratory-chain-related genes has frequently been overlooked. Correcting abnormal metabolic reprogramming, rescuing the "toxic respiratory chain", and targeting the clearance of mitochondrial reactive oxygen species are potential therapies for treating chronic kidney failure. These treatments have shown promising results in slowing fibrosis and inflammation progression and improving kidney function in various animal models of chronic kidney failure and patients with chronic kidney disease (CKD). The mitochondrial respiratory chain is a key target worthy of attention in the treatment of chronic kidney failure. This review integrated research related to the mitochondrial respiratory chain and chronic kidney failure, primarily elucidating the pathological status of the mitochondrial respiratory chain in chronic kidney failure and potential therapeutic drugs. It provided new ideas for the treatment of kidney failure and promoted the development of drugs targeting the mitochondrial respiratory chain.