Emanuel Guajardo-Correa

Cardiorenal syndrome (CRS) is characterized by bidirectional heart–kidney dysfunction in which oxidative stress, inflammation, and mitochondrial dysfunction drive progressive kidney injury, but the role of mitochondrial calcium (Ca²⁺) handling through the mitochondrial calcium uniporter (MCU) complex remains unclear. Here we show, in a mouse model of CRS induced by angiotensin II and L-NAME in male mice (C57BL/6), that renal mitochondria exhibit increased MCU expression, reduced Ca²⁺ retention capacity, and greater susceptibility to Ca²⁺-induced permeability transition, alongside impaired respiration, reduced PGC-1α and TFAM expression, oxidative stress, and inflammatory activation. Cannabidiol (CBD) attenuates renal dysfunction and structural injury, restores mitochondrial respiratory capacity and complex I activity, normalizes MCU expression, and partially improves mitochondrial Ca²⁺ handling, independently of blood pressure reduction. These findings identify MCU-dependent mitochondrial Ca²⁺ dysregulation as a candidate mechanism linking mitochondrial dysfunction to renal injury in CRS, and a potential target for CBD’s nephroprotective effects.

Calcium (Ca²⁺) is a crucial signaling molecule that significantly influences various cellular processes, including mitochondrial respiration, ATP production, and autophagy. Within the mitochondria, Ca²⁺ enters through the mitochondrial Ca²⁺ uniporter (MCU), which is a low-affinity, high-capacity ion channel driven by the negative membrane potential. This uptake of Ca²⁺ is essential for regulating ATP synthesis, primarily by activating calcium-dependent dehydrogenases. Under both resting and stress conditions, the MCU aligns mitochondrial energy production with the increased demands of cardiac cells, particularly in terms of contractility and Ca2+ handling. Dysregulation of the MCU has been linked to several cardiovascular diseases. For instance, its deletion has been shown to reduce myocardial injury during ischemia-reperfusion (I/R) events by preventing Ca2+ overload, mitochondrial dysfunction, and oxidative stress. In contrast, during heart failure (HF) and cardiac hypertrophy, moderate overexpression of the MCU has been found to enhance cardiac contractility, while excessive expression can lead to mitochondrial Ca2+ overload, worsening oxidative damage. The regulatory subunits of the MCU complex, including the MICU1-MICU2 complex and the essential MCU regulator (EMRE), play crucial roles in maintaining Ca2+ homeostasis. MICU proteins function as gatekeepers, regulating calcium influx in response to cytosolic Ca2+ levels, while EMRE is crucial for the structural and functional integrity of the MCU. Targeting these subunits could offer a promising therapeutic strategy for managing cardiovascular diseases. Overall, the regulatory functions of the MCU and potential pharmacological or molecular interventions targeting mitochondrial Ca2+ homeostasis are crucial for maintaining cardiac health and preventing the progression of cardiovascular disorders.

Cardiac hypertrophy is a cellular process characterized by the increased size of cardiomyocytes in response to a high workload or stress. 17-beta estradiol (E2) has cardioprotective and anti-hypertrophic effects by maintaining mitochondrial network and function. MUL1 is a mitochondrial ubiquitin ligase directly involved in the control of mitochondrial fission and mitophagy. Studies from our group and others have previously shown that cardiomyocyte hypertrophy is associated with mitochondrial fission and dysfunction. These findings led us to study in vitro whether E2 regulates MUL1 to prevent cardiac hypertrophy, mitochondrial fission, and dysfunction induced by the catecholamine norepinephrine (NE). Our results showed that NE induces hypertrophy in cultured rat cardiomyocytes. Pre-treatment with E2 (10-100 nM) prevented the NE-dependent increases in cell perimeter and the hypertrophic stress markers ANP and BNP at both the protein and mRNA levels. NE induced the fragmentation of the mitochondrial network and reduced ATP levels, effects that were both prevented by E2. In silico analysis suggested a putative binding site for estrogen receptors on the MUL1 gene promoter. In accordance with this finding, E2 prevented increases in MUL1 mRNA and protein levels induced by NE. Our data also showed that a siRNA MUL1 knockdown counteracted NE-induced cardiomyocyte hypertrophy and mitochondrial dysfunction, mirroring the protective effect triggered by E2. In contrast, a MUL1 adenovirus did not prevent the E2 protection from cardiomyocyte hypertrophy. Further, in vivo analysis in a transgenic mouse model overexpressing MUL1 revealed that only young male mice overexpressed the protein. Consequently, they exhibited increased levels of the hypertrophic marker ANP, an elevated heart weight, and larger cardiomyocyte size. Therefore, our data demonstrate that 17-beta estradiol prevents cardiac myocyte hypertrophy by regulating MUL1.

The estrogen metabolite 2-methoxyestradiol (2ME) is a promissory anticancer drug mainly because of its pro-apoptotic properties in cancer cells. However, the therapeutic use of 2ME has been hampered due to its low solubility and bioavailability. Thus, it is necessary to find new ways of administration for 2ME. Zeolites are inorganic aluminosilicates with a porous structure and are considered good adsorbents and sieves in the pharmaceutical field. Here, mordenite-type zeolite nanoparticles were loaded with 2ME to assess its efficiency as a delivery system for prostate cancer treatment. The 2ME-loaded zeolite nanoparticles showed an irregular morphology with a mean hydrodynamic diameter of 250.9 ± 11.4 nm, polydispersity index of 0.36 ± 0.04, and a net negative surface charge of −34 ± 1.73 meV. Spectroscopy with UV-vis and Attenuated Total Reflectance Infrared Fourier-Transform was used to elucidate the interaction between the 2ME molecules and the zeolite framework showing the formation of a 2ME-zeolite conjugate in the nanocomposite. The studies of adsorption and liberation determined that zeolite nanoparticles incorporated 40% of 2ME while the liberation of 2ME reached 90% at pH 7.4 after 7 days. The 2ME-loaded zeolite nanoparticles also decreased the viability and increased the mRNA of the 2ME-target gene F-spondin, encoded by SPON1, in the human prostate cancer cell line LNCaP. Finally, the 2ME-loaded nanoparticles also decreased the viability of primary cultures from mouse prostate cancer. These results show the development of 2ME-loaded zeolite nanoparticles with physicochemical and biological properties compatible with anticancer activity on the human prostate and highlight that zeolite nanoparticles can be a good carrier system for 2ME.

: In brief: Mating shuts down the 2-methoxyestradiol (2ME) nongenomic pathway that accelerates oviductal egg transport in the rat. This study shows that sperm cells, but not vaginocervical stimulation, utilize TNF-α to shut down this 2ME nongenomic pathway. The transport of oocytes or embryos throughout the oviduct to the implantation site in the uterus is defined as egg transport. In the rat, 2-methoxyestradiol (2ME) accelerates egg transport through the oviduct via a nongenomic pathway. Mating is known to shut down this 2ME pathway and then trigger an estradiol genomic pathway that accelerates egg transport. Here, we tested whether intrauterine insemination (IUI) or vaginocervical stimulation (VCS) shuts down the 2ME nongenomic pathway that accelerates egg transport, and if these mating components require tumor necrosis factor alpha (TNF-α). Levels of TNF-α and the mRNA for TNF-α receptors were measured in the oviduct of IUI or VCS rats. The tissue distribution of TNF-α receptor proteins and the concentration of the mRNA for catechol-O-methyl transferase (Comt) and 2ME were also analyzed in the oviduct. Finally, we assessed whether 2ME accelerates egg transport in IUI or VCS rats previously treated with the TNF-α antagonist W9P9QY. Results show that IUI, but not VCS, increased TNF-α and their receptors in the oviduct. IUI and VCS did not change the tissue distribution of TNF-α receptors; however, both decreased the oviductal concentration of Comt and 2ME. IUI and VCS each blocked the 2ME-induced egg transport acceleration; however, only the IUI was antagonized by the TNF-α antagonist. We concluded that IUI and VCS inhibit the 2ME nongenomic pathway that accelerates egg transport; however, the modes of action are distinct, with a TNF-α increase on spermatozoa presence being required for the shutdown of the 2ME pathway.

Benign Prostatic Hyperplasia (BPH) affects, worldwide, 50% of 60‐year‐old men. The Peruvian plant red maca (Lepidium meyenii) inhibits BPH in rodents. This study aimed to determine the effects of methanolic red maca extract and its n‐butanol and aqueous fractions on expression of androgen and oestrogen receptors in rats with testosterone enanthate‐induced BPH. Thirty‐six rats in six groups were studied. Control group received 2 mL of vehicle orally and 0.1 mL of propylene glycol intramuscularly. The second group received vehicle orally and testosterone enanthate (TE) (25 mg/0.1 mL) intramuscularly in days 1 and 7. The other four groups were BPH‐induced with TE and received, during 21 days, 3.78 mg/mL of finasteride, 18.3 mg/mL methanol extract of red maca, 2 mg/mL of n‐butanol fraction, or 16.3 mg/mL of aqueous fraction from red maca. Treatments with red maca extract and its n‐butanol but not aqueous fraction reduced prostate weight similar to finasteride. All maca treated groups restored the expression of ERβ, but only the aqueous fraction increased androgen receptors and ERα. In conclusion, butanol fraction of red maca reduced prostate size in BPH by restoring expression of ERβ without affecting androgen receptors and ERα. This effect was not observed with aqueous fraction of methanolic extract of red maca.