Functional characterization and evolution of PTH/PTHrP receptors: insights from the chicken

Characterization of the C5H11ORF96 gene in chickens: cloning, tissue distribution and investigation of its potential function in stress response regulation

Chicken is an important economic animal that encounter various stressors including high temperature, high stocking density, bacterial infections and transportation, etc. affecting the poultry production with serious economic loss. To be in response to the varied stimulus, the hypothalamic-pituitary-adrenal (HPA) axis is activated through the controlling of the synthesis and secretion of glucocorticoids (GCs). Present study characterized a novel gene C5H11ORF96, that demonstrated significant upregulation after the DEX injection in chicken, which simulates the stress stimulus. Our results showed that: (1) cC5H11ORF96 cDNA encodes a 120 amino acids protein, which shares high sequence identity with that of birds, mammals, reptiles, frogs and fish; (2) cC5H11ORF96 has a fully conserved RFKTQP motif and high proportion of serine, indicating its multiple potential phosphorylation sites; (3) cC5H11ORF96 is widely expressed in various chicken tissues, with high expression levels in the parathyroid gland, adrenal gland, and pituitary; (4) glucocorticoids (GCs) and stress significantly upregulate C5H11ORF96 mRNA and protein expression in the chicken pituitary and hypothalamus, suggesting its involvement in regulating stress response by influencing the negative feedback of GCs on the HPA axis in chickens. The characterization of the C5H11ORF96 gene in the chicken stress response provides potential targets for stress adaptability and poultry production. Meanwhile, our finding provides essential insights into the physiological functions of C11ORF96 gene in vertebrates.

Physiological changes in the regulation of calcium and phosphorus utilization that occur after the onset of egg production in commercial laying hens

At the onset of egg production, physiological changes governing calcium and phosphorus utilization must occur to meet demands for medullary bone formation and eggshell mineralization. The objective of this study was to identify these changes and determine if they are influenced by dietary supplementation with 1α-hydroxycholecalciferol (AlphaD3™, Iluma Alliance). Commercial laying hens fed either a control or AlphaD3-supplemented diet beginning at 18 weeks of age were sampled at 18 (n = 8) and 31 weeks (n = 8/diet) to evaluate mRNA expression associated with calcium and phosphorus utilization in kidney, shell gland, ileum, and liver, circulating vitamin D3 metabolites, and bone quality parameters in humerus, tibia, and keel bone. Though diet did not heavily influence gene expression at 31 weeks, several significant differences were observed between 18- and 31-week-old hens. Heightened sensitivity to hormones regulating calcium and phosphorus homeostasis was observed at 31 weeks, indicated by increased parathyroid hormone receptor 1, calcium-sensing receptor, calcitonin receptor, and fibroblast growth factor 23 receptors in several tissues. Increased renal expression of 25-hydroxylase and vitamin D binding protein ( DBP ) at 31 weeks suggests kidney participates in local vitamin D3 25-hydroxylation and DBP synthesis after egg production begins. Biologically active 1,25(OH)2D3 was higher at 31 weeks, with correspondingly lower inactive 24,25(OH)2D3. Increased expression of plasma membrane calcium ATPase 1 and calbindin in kidney, shell gland, and ileum suggests these are key facilitators of calcium uptake. Elevated renal inorganic phosphorus transporter 1 and 2 and sodium-dependent phosphate transporter IIa at 31 weeks suggests increased phosphorus excretion following hyperphosphatemia due to bone breakdown for eggshell formation. Diet did influence bone quality parameters. Bone mineral density in both humerus and tibia was higher in AlphaD3-supplemented hens at 31 weeks. Tibial bone mineral content increased between 18 and 31 weeks, with AlphaD3-supplemented hens increasing more than control hens. Moreover, control hens exhibited diminished tibial breaking strength at 31 weeks compared to hens at 18 weeks, while AlphaD3-supplemented hens did not. Together, these results indicate supplementation with AlphaD3 enhanced bone mineralization during the medullary bone formation period and elucidate the adaptive pathways regulating calcium and phosphorus utilization after the onset of lay.

Photocontrolled Reversible Amyloid Fibril Formation of Parathyroid Hormone-Derived Peptides

Peptide fibrillization is crucial in biological processes such as amyloid-related diseases and hormone storage, involving complex transitions between folded, unfolded, and aggregated states. We here employ light to induce reversible transitions between aggregated and nonaggregated states of a peptide, linked to the parathyroid hormone (PTH). The artificial light-switch 3-{[(4-aminomethyl)phenyl]diazenyl}benzoic acid (AMPB) is embedded into a segment of PTH, the peptide PTH25-37, to control aggregation, revealing position-dependent effects. Through in silico design, synthesis, and experimental validation of 11 novel PTH25-37-derived peptides, we predict and confirm the amyloid-forming capabilities of the AMPB-containing peptides. Quantum-chemical studies shed light on the photoswitching mechanism. Solid-state NMR studies suggest that β-strands are aligned parallel in fibrils of PTH25-37, while in one of the AMPB-containing peptides, β-strands are antiparallel. Simulations further highlight the significance of π-π interactions in the latter. This multifaceted approach enabled the identification of a peptide that can undergo repeated phototriggered transitions between fibrillated and defibrillated states, as demonstrated by different spectroscopic techniques. With this strategy, we unlock the potential to manipulate PTH to reversibly switch between active and inactive aggregated states, representing the first observation of a photostimulus-responsive hormone.

Symbiogenesis redicts the monism of the cosmos

Symbiogenesis has been systematically exploited to understand consciousness as the aggregate of our physiology. The Symbiogenic mechanism for assimilation of factors in the environment formulates the continuum from inside the cell to the Cosmos, both consciousness and cosmology complying with the Laws of Nature. Since Symbiogenesis is 'constructive', whereas eliminating what threatens us is 'destructive', why do we largely practice Symbiogenesis? Hypothetically, Symbiogenesis recursively simulates the monism of our origin, recognizing 'something bigger than ourselves'. That perspective explains many heretofore unexplained aspects of consciousness, such as mind, epigenetic inheritance, physiology, behaviors, social systems, mathematics, the Arts, from an a priori perspective. Moreover, there is an energetic continuum from Newtonian to Quantum Mechanics, opening up to a novel way of understanding the 'true nature of our being', not as 'materialism', but instead being the serial homeostatic control of energy. The latter is consistent with the spirit of Claude Bernard and Walter B. Cannon's perspectives on physiology. Such a paradigm shift is overdue, given that materialism is causing the destruction of the Earth and ourselves.

Revisiting the evolution of Family B1 GPCRs and ligands: Insights from mollusca

Family B1 G protein-coupled receptors (GPCRs) are one of the most well studied neuropeptide receptor families since they play a central role in many biological processes including endocrine, gastrointestinal, cardiovascular and reproduction in animals. The genes for these receptors emerged from a common ancestral gene in bilaterian genomes and evolved via gene/genome duplications and deletions in vertebrate and invertebrate genomes. Their existence and function have mostly been characterized in vertebrates and few studies exist in invertebrate species. Recently, an increased interest in molluscs, means a series of genomes have become available, and since they are less modified than insect and nematode genomes, they are ideal to explore the origin and evolution of neuropeptide gene families. This review provides an overview of Family B1 GPCRs and their peptide ligands and incorporates new data obtained from Mollusca genomes and taking a comparative approach challenges existing models on their origin and evolution.

The synchronic, diachronic cell as the holism of consciousness

The cell is both synchronic and diachronic, based on ontogeny and phylogeny, respectively. As experimental evidence for this holism, absent gravitational force, differentiated lung and bone cells devolve, losing their phenotypes, losing their evolutionary status, reverting to their nonlocal status. Thus, when evolution is seen as serial homeostasis, it is homologous with Quantum Entanglement as the nonlocal means of maintaining homeostatic balance between particles. This monadic perspective on consciousness is one-hundred and eighty degrees out of synch with the conventional way of thinking about consciousness as a diad, or mind and brain. There have been many attempts to explain consciousness, virtually all of them based on the brain as mind. The working hypothesis is that consciousness is a holism constituted by the unicell, the lipid cell membrane forming a barrier between inside and outside of the cell's environment as a topology. Conceptually, both the unicell and 'two hands clapping' are holisms, but because the cell is constituted by the ambiguity of negative entropy, and 'one hand clapping' requires two hands, they are both pseudo-holisms, constantly striving to be whole again. In the case of the cell, it is incomplete in the sense that there are factors in the ever-changing environment that can homeostatically complete it. That process results in biochemical modification of specific DNA codes in the egg or sperm so that the offspring is able to adapt in subsequent generations epigenetically. The opportunity to trace the evolution of the breath from humans to fish opens up to the further revelation of the interplay between evolution and geological change, tracing it back to invertebrates, sponges, and ultimately to unicellular organisms. And therein is evidence that the Cosmos itself 'breathes', providing the ultimate celestial fundament for this trail of holisms.

The holism of evolution as consciousness

Quantum Entanglement has been hypothesized to mediate non-local consciousness, underlying which, empirically, is the force of gravity. Upon further reflection, the case can be made for 'the breath' as the physiologic trait that binds all of these properties together, offering further opportunity for hypothesis testing experimentation. Humans have inexplicably made extraordinary intellectual and technical advances within a relatively very short period of time, referred to as the 'great leap forward'. It would be of great value if we could identify how and why we have evolved so rapidly. There is a holotropism that begins with the Big Bang that is centered on the homeostatic control of energy, perpetually referencing the First Principles of Physiology. "The Breath" is how and why our physiology has managed to perpetuate our species, and perhaps why the lung has been 'over-engineered' in order to facilitate the role of breathing in consciousness.

Circadian regulation of calcium and phosphorus homeostasis during the oviposition cycle in laying hens

Maintenance of calcium and phosphorus homeostasis in laying hens is crucial for preservation of skeletal integrity and eggshell quality, though physiological regulation of these systems is incompletely defined. To investigate changes in mineral and vitamin D3 homeostasis during the 24-h egg formation cycle, 32-wk-old commercial laying hens were sampled at 1, 3, 4, 6, 7, 8, 12, 15, 18, 21, 23, and 24 h post-oviposition (HPOP; n ≥ 4). Ovum location and egg calcification stage were recorded, and blood chemistry, plasma vitamin D3 metabolites, circulating parathyroid hormone (PTH), and expression of genes mediating uptake and utilization of calcium and phosphorus were evaluated. Elevated levels of renal 25-hydroxylase from 12 to 23 HPOP suggest this tissue might play a role in vitamin D3 25-hydroxylation during eggshell calcification. In shell gland, retinoid-x-receptor gamma upregulation between 6 and 8 HPOP followed by subsequently increased vitamin D receptor indicate that vitamin D3 signaling is important for eggshell calcification. Increased expression of PTH, calcitonin, and fibroblast growth factor 23 (FGF23) receptors in the shell gland between 18 and 24 HPOP suggest elevated sensitivity to these hormones toward the end of eggshell calcification. Shell gland sodium-calcium exchanger 1 was upregulated between 4 and 7 HPOP and plasma membrane calcium ATPase 1 increased throughout eggshell calcification, suggesting the primary calcium transporter may differ according to eggshell calcification stage. Expression in shell gland further indicated that bicarbonate synthesis precedes transport, where genes peaked at 6 to 7 and 12 to 18 HPOP, respectively. Inorganic phosphorus transporter 1 (PiT-1) expression peaked in kidney between 12 and 15 HPOP, likely to excrete excess circulating phosphorus, and in shell gland between 18 and 21 HPOP. Upregulation of FGF23 receptors and PiT-1 during late eggshell calcification suggest shell gland phosphorus uptake is important at this time. Together, these findings identified potentially novel hormonal pathways involved in calcium and phosphorus homeostasis along with associated circadian patterns in gene expression that can be used to devise strategies aimed at improving eggshell and skeletal strength in laying hens.

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Cybernetics as a conversation with the Cosmos

Norbert Wiener was the first to functionally define cybernetics as "the study of control and communication in the animal and the machine". Herein, it is shown that as a manifestation of physiology, cybernetics can be further reduced to cell-cell signaling to maintain homeostasis, bridging Newtonian 3rd Order Cybernetics with Quantum Mechanical 4th Order Cybernetics as our 'conversation with the Cosmos' based on Quantum Entanglement, constrained by non-localization. As such, cybernetics can be scientifically tested in toto from the functional to the metaphysical, rendered physical as communication for the first time. If that is correct, then the sooner we begin operating based on Quantum Mechanical principles, the sooner we will function based on predictive algorithms.

Regulation of Stanniocalcin Secretion by Calcium and PTHrP in Gilthead Seabream (Sparus aurata)

Calcium balance is of paramount importance for vertebrates. In fish, the endocrine modulators of calcium homeostasis include the stanniocalcin (STC), and some members of the parathyroid hormone (PTH) family, such as the PTH-related protein (PTHrP), acting as antagonists. STC is ubiquitously expressed in higher vertebrates. In turn, bony fish exhibit specific STC-producing glands named the corpuscles of Stannius (CS). Previous studies pointed to a calcium-sensing receptor (CaSR) involvement in the secretion of STC, but little is known of the involvement of other putative regulators. The CS provides a unique model to deepen the study of STC secretion. We developed an ex vivo assay to culture CS of fish and a competitive ELISA method to measure STC concentrations. As expected, STC released from the CS responds to CaSR stimulation by calcium, calcimimetics, and calcilytic drugs. Moreover, we uncover the presence (by PCR) of two PTHrP receptors in the CS, e.g., PTH1R and PTH3R. Thus, ex vivo incubations revealed a dose-response inhibition of STC secretion in response to PTHrP at basal Ca2+ concentrations. This inhibition is achieved through specific and reversible second messenger pathways (transmembrane adenylyl cyclases and phospholipase C), as the use of specific inhibitors highlights. Together, these results provide evidence for endocrine modulation between two antagonist hormones, STC and PTHrP.

Life is a mobius strip

If you cut a mobius strip in half, the edges form a Trefoil Knot, which can be untied to form a circle, proving it's a true mathematical knot. The cell is a homologue of the mathematical knot since it, too, must be able to unknot itself to form the egg and sperm meiotically in order to reproduce. The homology between a knot and a cell is thought-provoking biologically because the Trefoil Knot is a metaphor for the endoderm, ectoderm and mesoderm, the three germ layers of the gastrula that ultimately produce the embryo, beginning with the zygote. Upon further consideration, the cell membrane is like a mobius strip, forming one continuous surface between the inner environment of the cell and the outer environment. However, it is not formed by taking a circular surface, cutting it, twisting it and attaching the two ends as you would conventionally to form a mobius strip. Conversely, David Bohm's Explicate Order forms a boundary with the Implicate Order. That lipid boundary is the prima facie mobius strip that divides the infinite surface of the Implicate Order into inside and outside by 'recalling' its pre-adapted state as lipid molecules before there was an inside or outside.

Cellular evolution of language

The evolutionary origin of language remains unknown despite many efforts to determine the origin of this signature human trait. Based on epigenetic inheritance, the current article hypothesizes that language evolved from cell-cell communication as the basis for generating structure and function embryologically and phylogenetically, as did all physiologic traits. Beginning with lipids forming the first micelle, a vertical integration of the evolved properties of the cell, from multicellular organisms to the introduction of cholesterol into the cell membrane, to the evolution of the peroxisome, the water-land transition and duplication of the βAdrenergic Receptor, the evolution of endothermy, leading to bipedalism, freeing the forelimbs for toolmaking and language, selection pressure for myelinization of the central nervous system to facilitate calcium flux, bespeaks human expression, culminating in the evolution of civilization. This process is epitomized by the Area of Broca as the structural-functional site for both motor control and language formation. The mechanistic interrelationship between motor control and language formation is underscored by the role of FoxP2 gene expression in both bipedalism and language. The effect of endothermy on bipedalism, freeing the forelimbs for toolmaking and language as the vertical integration from Cosmology to Physiology as the basis for language bespeaks human expression.

A new neuropeptide insect parathyroid hormone iPTH in the red flour beetle Tribolium castaneum

In the postgenomics era, comparative genomics have advanced the understanding of evolutionary processes of neuropeptidergic signaling systems. The evolutionary origin of many neuropeptidergic signaling systems can be traced date back to early metazoan evolution based on the conserved sequences. Insect parathyroid hormone receptor (iPTHR) was previously described as an ortholog of vertebrate PTHR that has a well-known function in controlling bone remodeling. However, there was no sequence homologous to PTH sequence in insect genomes, leaving the iPTHR as an orphan receptor. Here, we identified the authentic ligand insect PTH (iPTH) for the iPTHR. The taxonomic distribution of iPTHR, which is lacking in Diptera and Lepidoptera, provided a lead for identifying the authentic ligand. We found that a previously described orphan ligand known as PXXXamide (where X is any amino acid) described in the cuttlefish Sepia officinalis has a similar taxonomic distribution pattern as iPTHR. Tests of this peptide, iPTH, in functional reporter assays confirmed the interaction of the ligand-receptor pair. Study of a model beetle, Tribolium castaneum, was used to investigate the function of the iPTH signaling system by RNA interference followed by RNA sequencing and phenotyping. The results suggested that the iPTH system is likely involved in the regulation of cuticle formation that culminates with a phenotype of defects in wing exoskeleton maturation at the time of adult eclosion. Moreover, RNAi of iPTHRs also led to significant reductions in egg numbers and hatching rates after parental RNAi.

Vertebrate parathyroid hormone (PTH) and its receptors have been extensively studied with respect to their function in bone remodeling and calcium metabolism. Insect parathyroid hormone receptors (iPTHRs) have been previously described as counterparts of vertebrate PTHRs, however, they are still orphan receptors for which the authentic ligands and biological functions remain unknown. We describe an insect form of parathyroid hormone (iPTH) by analyzing its interactions with iPTHRs. Identification of this new insect peptidergic system proved that the PTH system is an ancestral signaling system dating back to the evolutionary time before the divergence of protostomes and deuterostomes. We also investigated the functions of the iPTH system in a model beetle Tribolium castaneum by using RNA interference. RNA interference of iPTHR resulted in defects in wing exoskeleton maturation and fecundity. Based on the differential gene expression patterns and the phenotype induced by RNAi, we propose that the iPTH system is likely involved in the regulation of exoskeletal cuticle formation and fecundity in insects.

Reappraising the exteriorization of the mammalian testes through evolutionary physiology

A number of theories have been proposed to explain the exteriorization of the testicles in most mammalian species. None of these provide a consistent account for the wide variety of testicular locations found across the animal kingdom. It is proposed that testicular location is the result of coordinate action of testicular tissue ecologies to sustain preferential states of homeostatic equipoise throughout evolutionary development in response to the advent of endothermy.

STC1 and PTHrP Modify Carbohydrate and Lipid Metabolism in Liver of a Teleost Fish

Stanniocalcin 1 (STC1) and parathyroid hormone-related protein (PTHrP) are calciotropic hormones in vertebrates. Here, a recently hypothesized metabolic role for these hormones is tested on European sea bass treated with: (i) teleost PTHrP(1-34), (ii) PTHrP(1-34) and anti-STC1 serum (pro-PTHrP groups), (iii) a PTHrP antagonist PTHrP(7-34) or (iv) PTHrP(7-34) and STC1 (pro-STC1 groups). Livers were analysed using untargeted metabolic profiling based on proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Concentrations of branched-chain amino acid (BCAA), alanine, glutamine and glutamate increased in pro-STC1 groups suggesting their mobilization from the muscle to the liver for degradation and gluconeogenesis from alanine and glutamine. In addition, only STC1 treatment decreased the concentrations of succinate, fumarate and acetate, indicating slowing of the citric acid cycle. In the pro-PTHrP groups the concentrations of glucose, erythritol and lactate decreased, indicative of gluconeogenesis from lactate. Taurine, trimethylamine, trimethylamine N-oxide and carnitine changed in opposite directions in the pro-STC1 versus the pro-PTHrP groups, suggesting opposite effects, with STC1 stimulating lipogenesis and PTHrP activating lipolysis/β-oxidation of fatty acids. These findings suggest a role for STC1 and PTHrP related to strategic energy mechanisms that involve the production of glucose and safeguard of liver glycogen reserves for stressful situations.

Progress of Regenerative Therapy in Orthopedics

PURPOSE OF REVIEW

To conduct a thorough appraisal of recent and inventive advances in the field of bone tissue engineering using biomaterials, cell-based research, along with the incorporation of biomimetic properties using surface modification of scaffolds.

RECENT FINDINGS

This paper will provide an overview on different biomaterials and emerging techniques involved in the fabrication of scaffolds, brief description of signaling pathways involved in osteogenesis, and the effect of surface modification on the fate of progenitor cells. The current strategies used for regenerative medicine like cell therapy, gene transfer, and tissue engineering have opened numerous therapeutic avenues for the treatment of various disabling orthopedic disorders. Precise strategy utilized for the reconstruction, restoration, or repair of the bone-related tissues exploits cells, biomaterials, morphogenetic signals, and appropriate mechanical environment to provide the basic constituents required for creating new tissue. Combining all the above strategies in clinical trials would pave the way for successful "bench to bedside" transformation in bone healing.

Unitary Physiology

The common relationships among a great variety of biological phenomena seem enigmatic when considered solely at the level of the phenotype. The deep connections in physiology, for example, between the effects of maternal food restriction in utero and the subsequent incidence of metabolic syndrome in offspring, the effects of microgravity on cell polarity and reproduction in yeast, stress effects on jellyfish, and their endless longevity, or the relationship between nutrient abundance and the colonial form in slime molds, are not apparent by phenotypic observation. Yet all of these phenomena are ultimately determined by the Target of Rapamycin (TOR) gene and its associated signaling complexes. In the same manner, the unfolding of evolutionary physiology can be explained by a comparable application of the common principle of cell-cell signaling extending across complex developmental and phylogenetic traits. It is asserted that a critical set of physiologic and phenotypic adaptations emanated from a few crucial, ancestral receptor gene duplications that enabled the successful terrestrial transition of vertebrates from water to land. In combination, mTor and its cognate receptors and a few crucial genetic duplications provide a mechanistic common denominator across a diverse spectrum of biological responses. The proper understanding of their purpose yields a unified concept of physiology and its evolutionary development. © 2018 American Physiological Society. Compr Physiol 8:761-771, 2018.

PTH Reloaded: A New Evolutionary Perspective

The parathyroid hormone (PTH) family is a group of structurally-related secreted peptides involved in bone mineral homeostasis and multitude of developmental processes in vertebrates. These peptides mediate actions through PTH receptors (PTHRs), which belong to the transmembrane G protein-coupled receptor group. To date, genes encoding for PTH and PTHR have only been identified in chordates, suggesting that this signaling pathway may be an evolutionary innovation of our phylum. In vertebrates, we found up to six PTH and three PTHR different paralogs, varying in number between mammals and teleost fishes due to the different rounds of whole-genome duplication and specific gene losses suffered between the two groups of animals. The diversification of the PTH gene family has been accompanied by both functional divergence and convergence, making sometimes difficult the comparison between PTH peptides of teleosts and mammals. Here, we review the roles of all Pth peptides in fishes, and based on the evolutionary history of PTH paralogs, we propose a new and simple nomenclature from PTH1 to PTH4. Moreover, the recent characterization of the Pth4 in zebrafish allows us to consider the prominent role of the brain-to-bone signaling pathway in the regulation of bone development and homeostasis. Finally, comparison between PTH peptides of fish and mammals allows us to discuss an evolutionary model for PTH functions related to bone mineral balance during the vertebrate transition from an aquatic to a terrestrial environment.

The Molecular Apgar Score: A Key to Unlocking Evolutionary Principles

One of the first "tools" used for systematically evaluating successful newborn transitional physiology at birth was the Apgar Score, devised by Virginia Apgar in 1953. This objective assessment tool allowed clinicians to immediately gauge the relative success of a newborn infant making the transition from the in utero liquid immersive environment to the ex utero gas environment in the delivery room during the first minutes after birth. The scoring system, although eponymous, is generally summarized as an acronym based on Appearance, Pulse, Grimace, Activity, and Respiration, criteria evaluated and scored at 1 and 5 min after birth. This common clinical appraisal is a guide for determining the elements of integrated physiology involved as the infant makes the transition from a "sea water" environment of 3% oxygen to a "land" environment in 21% oxygen. Appearance determines the perfusion of the skin with oxygenated blood-turning it pink; Pulse is the rate of heart beat, reflecting successful oxygen delivery to organs; Grimace, or irritability, is a functional marker for nervous system integration; Activity represents locomotor capacity; and, of course, Respiration represents pulmonary function as well as the successful neuro-feedback-mediated drive to breathe, supplying oxygen by inspiring atmospheric gas. Respiration, locomotion, and metabolism are fundamental processes adapted for vertebrate evolution from a water-based to an atmosphere-based life and are reflected by the Apgar Score. These physiologic processes last underwent major phylogenetic changes during the water-land transition some 300-400 million years ago, during which specific gene duplications occurred that facilitated terrestrial adaptation, in particular the parathyroid hormone-related protein receptor, the β-adrenergic receptor, and the glucocorticoid receptor. All these genetic traits and the gene regulatory networks they comprise represent the foundational substructure of the Apgar Score. As such, these molecular elements can be examined using a Molecular Apgar evaluation of keystone evolutionary events that predict successful evolutionary adaptation of physiologic functions necessary for neonatal transition and survival.

The Unicellular State as a Point Source in a Quantum Biological System

A point source is the central and most important point or place for any group of cohering phenomena. Evolutionary development presumes that biological processes are sequentially linked, but neither directed from, nor centralized within, any specific biologic structure or stage. However, such an epigenomic entity exists and its transforming effects can be understood through the obligatory recapitulation of all eukaryotic lifeforms through a zygotic unicellular phase. This requisite biological conjunction can now be properly assessed as the focal point of reconciliation between biology and quantum phenomena, illustrated by deconvoluting complex physiologic traits back to their unicellular origins.

Life Is Simple-Biologic Complexity Is an Epiphenomenon

Life originated from unicellular organisms by circumventing the Second Law of Thermodynamics using the First Principles of Physiology, namely negentropy, chemiosmosis and homeostatic regulation of calcium and lipids. It is hypothesized that multicellular organisms are merely contrivances or tools, used by unicellular organisms as agents for the acquisition of epigenetic inheritance. The First Principles of Physiology, which initially evolved in unicellular organisms are the exapted constraints that maintain, sustain and perpetuate that process. To ensure fidelity to this mechanism, we must return to the first principles of the unicellular state as the determinants of the primary level of selection pressure during the life cycle. The power of this approach is reflected by examples of its predictive value. This perspective on life is a "game changer", mechanistically rendering transparent many dogmas, teleologies and tautologies that constrain the current descriptive view of Biology.

On the Evolution of the Mammalian Brain

Hobson and Friston have hypothesized that the brain must actively dissipate heat in order to process information (Hobson et al., 2014). This physiologic trait is functionally homologous with the first instantation of life formed by lipids suspended in water forming micelles- allowing the reduction in entropy (heat dissipation). This circumvents the Second Law of Thermodynamics permitting the transfer of information between living entities, enabling them to perpetually glean information from the environment, that is felt by many to correspond to evolution per se. The next evolutionary milestone was the advent of cholesterol, embedded in the cell membranes of primordial eukaryotes, facilitating metabolism, oxygenation and locomotion, the triadic basis for vertebrate evolution. Lipids were key to homeostatic regulation of calcium, forming calcium channels. Cell membrane cholesterol also fostered metazoan evolution by forming lipid rafts for receptor-mediated cell-cell signaling, the origin of the endocrine system. The eukaryotic cell membrane exapted to all complex physiologic traits, including the lung and brain, which are molecularly homologous through the function of neuregulin, mediating both lung development and myelinization of neurons. That cooption later exapted as endothermy during the water-land transition (Torday, 2015a), perhaps being the functional homolog for brain heat dissipation and conscious/mindful information processing. The skin and brain similarly share molecular homologies through the “skin-brain” hypothesis, giving insight to the cellular-molecular “arc” of consciousness from its unicellular origins to integrated physiology. This perspective on the evolution of the central nervous system clarifies self-organization, reconciling thermodynamic and informational definitions of the underlying biophysical mechanisms, thereby elucidating relations between the predictive capabilities of the brain and self-organizational processes.

Heterochrony as Diachronically Modified Cell-Cell Interactions

Heterochrony is an enabling concept in evolution theory that metaphorically captures the mechanism of biologic change due to mechanisms of growth and development. The spatio-temporal patterns of morphogenesis are determined by cell-to-cell signaling mediated by specific soluble growth factors and their cognate receptors on nearby cells of different germline origins. Subsequently, down-stream production of second messengers generates patterns of form and function. Environmental upheavals such as Romer’s hypothesized drying up of bodies of water globally caused the vertebrate water-land transition. That transition caused physiologic stress, modifying cell-cell signaling to generate terrestrial adaptations of the skeleton, lung, skin, kidney and brain. These tissue-specific remodeling events occurred as a result of the duplication of the Parathyroid Hormone-related Protein Receptor (PTHrPR) gene, expressed in mesodermal fibroblasts in close proximity to ubiquitously expressed endodermal PTHrP, amplifying this signaling pathway. Examples of how and why PTHrPR amplification affected the ontogeny, phylogeny, physiology and pathophysiology of the lung are used to substantiate and further our understanding through insights to the heterochronic mechanisms of evolution, such as the fish swim bladder evolving into the vertebrate lung, interrelated by such functional homologies as surfactant and mechanotransduction. Instead of the conventional description of this phenomenon, lung evolution can now be understood as adaptive changes in the cellular-molecular signaling mechanisms underlying its ontogeny and phylogeny.

What We Talk About When We Talk About Evolution

Currently, the biologic sciences are a Tower of Babel, having become so highly specialized that one discipline cannot effectively communicate with another. A mechanism for evolution that integrates development and physiologic homeostasis phylogenetically has been identified—cell-cell interactions. By reducing this process to ligand-receptor interactions and their intermediate down-stream signaling partners, it is possible, for example, to envision the functional homologies between such seemingly disparate structures and functions as the lung alveolus and kidney glomerulus, the skin and brain, or the skin and lung. For example, by showing the continuum of the lung phenotype for gas exchange at the cell-molecular level, being selected for increased surface area by augmenting lung surfactant production and function in lowering surface tension, we have determined an unprecedented structural-functional continuum from proximate to ultimate causation in evolution. It is maintained that tracing the changes in structure and function that have occurred over both the short-term history of the organism (as ontogeny), and the long-term history of the organism (as phylogeny), and how the mechanisms shared in common can account for both biologic stability and novelty, will provide the key to understanding the mechanisms of evolution. We need to better understand evolution from its unicellular origins as the Big Bang of biology.

On the evolution of the pulmonary alveolar lipofibroblast

The pulmonary alveolar lipofibroblast was first reported in 1970. Since then its development, structure, function and molecular characteristics have been determined. Its capacity to actively absorb, store and 'traffic' neutral lipid for protection of the alveolus against oxidant injury, and for the active supply of substrate for lung surfactant phospholipid production have offered the opportunity to identify a number of specialized functions of these strategically placed cells. Namely, Parathyroid Hormone-related Protein (PTHrP) signaling, expression of Adipocyte Differentiation Related Protein, leptin, peroxisome proliferator activator receptor gamma, and the prostaglandin E2 receptor EP2- which are all stretch-regulated, explaining how and why surfactant production is 'on-demand' in service to ventilation-perfusion matching. Because of the central role of the lipofibroblast in vertebrate lung physiologic evolution, it is a Rosetta Stone for understanding how and why the lung evolved in adaptation to terrestrial life, beginning with the duplication of the PTHrP Receptor some 300 mya. Moreover, such detailed knowledge of the workings of the lipofibroblast have provided insight to the etiology and effective treatment of Bronchopulmonary Dysplasia based on physiologic principles rather than on pharmacology.

Homeostasis as the Mechanism of Evolution

Homeostasis is conventionally thought of merely as a synchronic (same time) servo-mechanism that maintains the status quo for organismal physiology. However, when seen from the perspective of developmental physiology, homeostasis is a robust, dynamic, intergenerational, diachronic (across-time) mechanism for the maintenance, perpetuation and modification of physiologic structure and function. The integral relationships generated by cell-cell signaling for the mechanisms of embryogenesis, physiology and repair provide the needed insight to the scale-free universality of the homeostatic principle, offering a novel opportunity for a Systems approach to Biology. Starting with the inception of life itself, with the advent of reproduction during meiosis and mitosis, moving forward both ontogenetically and phylogenetically through the evolutionary steps involved in adaptation to an ever-changing environment, Biology and Evolution Theory need no longer default to teleology.

Pleiotropy as the Mechanism for Evolving Novelty: Same Signal, Different Result

In contrast to the probabilistic way of thinking about pleiotropy as the random expression of a single gene that generates two or more distinct phenotypic traits, it is actually a deterministic consequence of the evolution of complex physiology from the unicellular state. Pleiotropic novelties emerge through recombinations and permutations of cell-cell signaling exercised during reproduction based on both past and present physical and physiologic conditions, in service to the future needs of the organism for its continued survival. Functional homologies ranging from the lung to the kidney, skin, brain, thyroid and pituitary exemplify the evolutionary mechanistic strategy of pleiotropy. The power of this perspective is exemplified by the resolution of evolutionary gradualism and punctuated equilibrium in much the same way that Niels Bohr resolved the paradoxical duality of light as Complementarity.

A central theory of biology

The history of physiologic cellular-molecular interrelationships can be traced all the way back to the unicellular state by following the pathway formed by lipids ubiquitously accommodating calcium homeostasis, and its consequent adaptive effects on oxygen uptake by cells, tissues and organs. As a result, a cohesive, mechanistically integrated view of physiology can be formulated by recognizing the continuum comprising conception, development, physiologic homeostasis and death mediated by soluble growth factor signaling. Seeing such seemingly disparate processes as embryogenesis, chronic disease and dying as the gain and subsequent loss of cell-cell signaling provides a novel perspective for physiology and medicine. It is emblematic of the self-organizing, self-referential nature of life, starting from its origins. Such organizing principles obviate the pitfalls of teleologic evolution, conversely providing a way of resolving such seeming dichotomies as holism and reductionism, genotype and phenotype, emergence and contingence, proximate and ultimate causation in evolution, cells and organisms. The proposed approach is scale-free and predictive, offering a Central Theory of Biology.

Functional Pairing of Class B1 Ligand-GPCR in Cephalochordate Provides Evidence of the Origin of PTH and PACAP/Glucagon Receptor Family

Several hypotheses have been proposed regarding the origin and evolution of the secretin family of peptides and receptors. However, identification of homologous ligand-receptor pairs in invertebrates and vertebrates is difficult because of the low levels of sequence identity between orthologs of distant species. In this study, five receptors structurally related to the vertebrate class B1 G protein-coupled receptor (GPCR) family were characterized from amphioxus (Branchiostoma floridae). Phylogenetic analysis showed that they clustered with vertebrate parathyroid hormone receptors (PTHR) and pituitary adenylate cyclase-activating polypeptide (PACAP)/glucagon receptors. These PTHR-like receptors shared synteny with several PTH and PACAP/glucagon receptors identified in spotted gar, Xenopus, and human, indicating that amphioxus preserves the ancestral chordate genomic organization of these receptor subfamilies. According to recent data by Mirabeau and Joly, amphioxus also expresses putative peptide ligands including homologs of PTH (bfPTH1 and 2) and PACAP/GLUC-like peptides (bfPACAP/GLUCs) that may interact with these receptors. Functional analyses showed that bfPTH1 and bfPTH2 activated one of the amphioxus receptors (bf98C) whereas bfPACAP/GLUCs strongly interacted with bf95. In summary, our data confirm the presence of PTH and PACAP/GLUC ligand-receptor pairs in amphioxus, demonstrating that functional homologs of vertebrate PTH and PACAP/glucagon GPCR subfamilies arose before the cephalochordate divergence from the ancestor of tunicates and vertebrates.

PTHrP regulates water absorption and aquaporin expression in the intestine of the marine sea bream (Sparus aurata, L.)

Water ingestion by drinking is fundamental for ion homeostasis in marine fish. However, the fluid ingested requires processing to allow net water absorption in the intestine. The formation of luminal carbonate aggregates impacts on calcium homeostasis and requires epithelial HCO3(-) secretion to enable water absorption. In light of its endocrine importance in calcium handling and the indication of involvement in HCO3(-) secretion the present study was designed to expose the role of the parathyroid hormone-related protein (PTHrP) in HCO3(-) secretion, water absorption and the regulation of aqp1 gene expression in the anterior intestine of the sea bream. HCO3(-) secretion rapidly decreased when PTHrP(1-34) was added to anterior intestine of the sea bream mounted in Ussing chambers. The effect achieved a maximum inhibition of 60% of basal secretion rates, showing a threshold effective dose of 0.1 ng ml(-1) compatible with reported plasma values of PTHrP. When applied in combination with the adenylate cyclase inhibitor (SQ 22.536, 100 μmol l(-1)) or the phospholipase C inhibitor (U73122, 10 μmol l(-1)) the effect of PTHrP(1-34) on HCO3(-) secretion was reduced by about 50% in both cases. In parallel, bulk water absorption measured in intestinal sacs was sensitive to inhibition by PTHrP. The inhibitory action conforms to a typical dose-response curve in the range of 0.1-1000 ng ml(-1), achieves a maximal effect of 60-65% inhibition from basal rates and shows threshold significant effects at hormone levels of 0.1 ng ml(-1). The action of PTHrP in water absorption was completely abolished in the presence of the adenylate cyclase inhibitor (SQ 22.536, 100 μmol l(-1)) and was insensitive to the phospholipase C inhibitor (U73122, 10 μmol l(-1)). In vivo injections of PTHrP(1-34) or the PTH/PTHrP receptor antagonist PTHrP(7-34) evoked respectively, a significant decrease or increase of aqp1ab, but not aqp1a. Overall the present results suggest that PTHrP acts as a key regulator of carbonate aggregate formation in the intestine of marine fish via its actions on water absorption, calcium regulation and HCO3(-) secretion.

Bone-remodeling transcript levels are independent of perching in end-of-lay white leghorn chickens

Osteoporosis is a bone disease that commonly results in a 30% incidence of fracture in hens used to produce eggs for human consumption. One of the causes of osteoporosis is the lack of mechanical strain placed on weight-bearing bones. In conventionally-caged hens, there is inadequate space for chickens to exercise and induce mechanical strain on their bones. One approach is to encourage mechanical stress on bones by the addition of perches to conventional cages. Our study focuses on the molecular mechanism of bone remodeling in end-of-lay hens (71 weeks) with access to perches. We examined bone-specific transcripts that are actively involved during development and remodeling. Using real-time quantitative PCR, we examined seven transcripts (COL2A1 (collagen, type II, alpha 1), RANKL (receptor activator of nuclear factor kappa-B ligand), OPG (osteoprotegerin), PTHLH (PTH-like hormone), PTH1R (PTH/PTHLH type-1 receptor), PTH3R (PTH/PTHLH type-3 receptor), and SOX9 (Sry-related high mobility group box)) in phalange, tibia and femur. Our results indicate that the only significant effect was a difference among bones for COL2A1 (femur > phalange). Therefore, we conclude that access to a perch did not alter transcript expression. Furthermore, because hens have been used as a model for human bone metabolism and osteoporosis, the results indicate that bone remodeling due to mechanical loading in chickens may be a product of different pathways than those involved in the mammalian model.

International Union of Basic and Clinical Pharmacology. XCIII. The parathyroid hormone receptors--family B G protein-coupled receptors

The type-1 parathyroid hormone receptor (PTHR1) is a family B G protein-coupled receptor (GPCR) that mediates the actions of two polypeptide ligands; parathyroid hormone (PTH), an endocrine hormone that regulates the levels of calcium and inorganic phosphate in the blood by acting on bone and kidney, and PTH-related protein (PTHrP), a paracrine-factor that regulates cell differentiation and proliferation programs in developing bone and other tissues. The type-2 parathyroid hormone receptor (PTHR2) binds a peptide ligand, called tuberoinfundibular peptide-39 (TIP39), and while the biologic role of the PTHR2/TIP39 system is not as defined as that of the PTHR1, it likely plays a role in the central nervous system as well as in spermatogenesis. Mechanisms of action at these receptors have been explored through a variety of pharmacological and biochemical approaches, and the data obtained support a basic "two-site" mode of ligand binding now thought to be used by each of the family B peptide hormone GPCRs. Recent crystallographic studies on the family B GPCRs are providing new insights that help to further refine the specifics of the overall receptor architecture and modes of ligand docking. One intriguing pharmacological finding for the PTHR1 is that it can form surprisingly stable complexes with certain PTH/PTHrP ligand analogs and thereby mediate markedly prolonged cell signaling responses that persist even when the bulk of the complexes are found in internalized vesicles. The PTHR1 thus appears to be able to activate the Gα(s)/cAMP pathway not only from the plasma membrane but also from the endosomal domain. The cumulative findings could have an impact on efforts to develop new drug therapies for the PTH receptors.

Evolution of parathyroid hormone receptor family and their ligands in vertebrate

The presence of the parathyroid hormones in vertebrates, including PTH, PTH-related peptide (PTHrP), and tuberoinfundibular peptide of 39 residues (TIP39), has been proposed to be the result of two rounds of whole genome duplication in the beginning of vertebrate diversification. Bioinformatics analyses, in particular chromosomal synteny study and the characterization of the PTH ligands and their receptors from various vertebrate species, provide evidence that strongly supports this hypothesis. In this mini-review, we summarize recent advances in studies regarding the molecular evolution and physiology of the PTH ligands and their receptors, with particular focus on non-mammalian vertebrates. In summary, the PTH family of peptides probably predates early vertebrate evolution, indicating a more ancient existence as well as a function of these peptides in invertebrates.

Nematode and arthropod genomes provide new insights into the evolution of class 2 B1 GPCRs

Nematodes and arthropods are the most speciose animal groups and possess Class 2 B1 G-protein coupled receptors (GPCRs). Existing models of invertebrate Class 2 B1 GPCR evolution are mainly centered on Caenorhabditis elegans and Drosophila melanogaster and a few other nematode and arthropod representatives. The present study reevaluates the evolution of metazoan Class 2 B1 GPCRs and orthologues by exploring the receptors in several nematode and arthropod genomes and comparing them to the human receptors. Three novel receptor phylogenetic clusters were identified and designated cluster A, cluster B and PDF-R-related cluster. Clusters A and B were identified in several nematode and arthropod genomes but were absent from D. melanogaster and Culicidae genomes, whereas the majority of the members of the PDF-R-related cluster were from nematodes. Cluster A receptors were nematode and arthropod-specific but shared a conserved gene environment with human receptor loci. Cluster B members were orthologous to human GCGR, PTHR and Secretin members with which they probably shared a common origin. PDF-R and PDF-R related clusters were present in representatives of both nematodes and arthropods. The results of comparative analysis of GPCR evolution and diversity in protostomes confirm previous notions that C. elegans and D. melanogaster genomes are not good representatives of nematode and arthropod phyla. We hypothesize that at least four ancestral Class 2 B1 genes emerged early in the metazoan radiation, which after the protostome-deuterostome split underwent distinct selective pressures that resulted in duplication and deletion events that originated the current Class 2 B1 GPCRs in nematode and arthropod genomes.

Vitamin D: calcium and bone homeostasis during evolution

Vitamin D3 is already found early in the evolution of life but essentially as inactive end products of the photochemical reaction of 7-dehydrocholestol with ultraviolet light B. A full vitamin D (refers to vitamin D2 and D3) endocrine system, characterized by a specific VDR (vitamin D receptor, member of the nuclear receptor family), specific vitamin D metabolizing CYP450 enzymes regulated by calciotropic hormones and a dedicated plasma transport-protein is only found in vertebrates. In the earliest vertebrates (lamprey), vitamin D metabolism and VDR may well have originated from a duplication of a common PRX/VDR ancestor gene as part of a xenobiotic detoxification pathway. The vitamin D endocrine system, however, subsequently became an important regulator of calcium supply for an extensive calcified skeleton. Vitamin D is essential for normal calcium and bone homeostasis as shown by rickets in vitamin D-deficient growing amphibians, reptiles, birds and mammals. From amphibians onward, bone is gradually more dynamic with regulated bone resorption, mainly by combined action of PTH and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the generation and function of multinucleated osteoclasts. Therefore, bone functions as a large internal calcium reservoir, under the control of osteoclasts. Osteocytes also display a remarkable spectrum of activities, including mechanical sensing and regulating mineral homeostasis, but also have an important role in global nutritional and energy homeostasis. Mineralization from reptiles onward is under the control of well-regulated SIBLING proteins and associated enzymes, nearly all under the control of 1,25(OH)2D3. The vitamin D story thus started as inert molecule but gained an essential role for calcium and bone homeostasis in terrestrial animals to cope with the challenge of higher gravity and calcium-poor environment.

On the evolution of development

Perhaps development is more than just morphogenesis. We now recognize that the conceptus expresses epigenetic marks that heritably affect it phenotypically, indicating that the offspring are to some degree genetically autonomous, and that ontogeny and phylogeny may coordinately determine the fate of such marks. This scenario mechanistically links ecology, ontogeny and phylogeny together as an integrated mechanism for evolution for the first time. As a functional example, the Parathyroid Hormone-related Protein (PTHrP) signaling duplicated during the Phanerozoic water-land transition. The PTHrP signaling pathway was critical for the evolution of the skeleton, skin barrier, and lung function, based on experimental evidence, inferring that physiologic stress can profoundly affect adaptation through internal selection, giving seminal insights to how and why vertebrates were able to evolve from water to land. By viewing evolution from its inception in unicellular organisms, driven by competition between pro- and eukaryotes, the emergence of complex biologic traits from the unicellular cell membrane offers a novel way of thinking about the process of evolution from its beginnings, rather than from its consequences as is traditionally done. And by focusing on the epistatic balancing mechanisms for calcium and lipid homeostasis, the evolution of unicellular organisms, driven by competition between pro- and eukaryotes, gave rise to the emergence of complex biologic traits derived from the unicellular plasma lemma, offering a unique way of thinking about the process of evolution. By exploiting the cellular-molecular mechanisms of lung evolution as ontogeny and phylogeny, the sequence of events for the evolution of the skin, kidney and skeleton become more transparent. This novel approach to the evolution question offers equally novel insights to the primacy of the unicellular state, hologenomics and even a priori bioethical decisions.

Insight from the lamprey genome: glimpsing early vertebrate development via neuroendocrine-associated genes and shared synteny of gonadotropin-releasing hormone (GnRH)

Study of the ancient lineage of jawless vertebrates is key to understanding the origins of vertebrate biology. The establishment of the neuroendocrine system with the hypothalamic-pituitary axis at its crux is of particular interest. Key neuroendocrine hormones in this system include the pivotal gonadotropin-releasing hormones (GnRHs) responsible for controlling reproduction via the pituitary. Previous data incorporating several lines of evidence showed all known vertebrate GnRHs were grouped into four paralogous lineages: GnRH1, 2, 3 and 4; with proposed evolutionary paths. Using the currently available lamprey genome assembly, we searched genes of the neuroendocrine system and summarize here the details representing the state of the current lamprey genome assembly. Additionally, we have analyzed in greater detail the evolutionary history of the GnRHs based on the information of the genomic neighborhood of the paralogs in lamprey as compared to other gnathostomes. Significantly, the current evidence suggests that two genome duplication events (both 1R and 2R) that generated the different fish and tetrapod paralogs took place before the divergence of the ancestral agnathans and gnathostome lineages. Syntenic analysis supports this evidence in that the previously-classified type IV GnRHs in lamprey (lGnRH-I and -III) share a common ancestry with GnRH2 and 3, and thus are no longer considered type IV GnRHs. Given the single amino acid difference between lGnRH-II and GnRH2 we propose that a GnRH2-like gene existed before the lamprey/gnathostome split giving rise to lGnRH-II and GnRH2. Furthermore, paralogous type 3 genes (lGnRH-I/III and GnRH3) evolved divergent structure/function in lamprey and gnathostome lineages.

Evolution and Cell Physiology. 1. Cell signaling is all of biology

I hypothesize that the First Principles of Physiology (FPPs) were co-opted during the vertebrate transition from water to land, beginning with the acquisition of cholesterol by eukaryotes, facilitating unicellular evolution over the course of the first 4.5 billion years of the Earth's history, in service to the reduction in intracellular entropy, far from equilibrium. That mechanism was perpetuated by the advent of cholesterol in the cell membrane of unicellular eukaryotes, ultimately giving rise to the metazoan homologs of the gut, lung, kidney, skin, bone, and brain. Parathyroid hormone-related protein (PTHrP), whose cognate receptor underwent a gene duplication during the transition from fish to amphibians, facilitated gas exchange for the water-to-land transition, since PTHrP is necessary for the formation of lung alveoli: deletion of the PTHrP gene in mice causes the offspring to die within a few minutes of birth due to the absence of alveoli. Moreover, PTHrP is central to the development and homeostasis of the kidney, skin, gut, bone, and brain. Therefore, duplication of the PTHrP receptor gene is predicted to have facilitated the molecular evolution of all the necessary traits for land habitation through a common cellular and molecular motif. Subsequent duplication of the β-adrenergic receptor gene permitted blood pressure control within the lung microvasculature, allowing further evolution of the lung by increasing its surface area. I propose that such gene duplications were the result of shear stress on the microvasculature, locally generating radical oxygen species that caused DNA mutations, giving rise to duplication of the PTHrP and β-adrenergic receptor genes. I propose that one can determine the FPPs by systematically tracing the molecular homologies between the lung, skin, kidney, gut, bone, and brain across development, phylogeny, and pathophysiology as a type of "reverse evolution." By tracing such relationships back to unicellular organisms, one can use the underlying principles to predict homeostatic failure as disease, thereby also potentially forming the basis for maneuvers that can treat or even prevent such failure.